CERNMay/June 2020 cerncourier.com COURIERReporting on international high-energy physics WLCOMEE CERN Courier – digital edition Welcome to the digital edition of the May/June 2020 issue of CERN Courier.

This month’s issue looks at the latest progress in niobium-tin (Nb3Sn) accelerator SUPER magnets for high-energy exploration. Discovered to be a superconductor more than half a century ago, and already in widespread commercial use in MRI CONDUCTOR scanners and employed on a giant scale in the under-construction ITER fusion THE RISE OF experiment, it is only recently that high-performance accelerator magnets made NIOBIUM-TIN from Nb3Sn have been mastered. The first use of Nb3Sn conductor in accelerator magnets will be the High-Luminosity LHC (HL-LHC), for which the first

Nb3Sn dipole and quadrupole magnets have recently been tested successfully at CERN and in the US. As our cover feature describes, the demonstration of

Nb3Sn in the HL-LHC also serves as a springboard to future hadron colliders, enabling physicists to reach significantly higher energies than are possible with present-generation niobium-titanium accelerator magnets. To this end, CERN and the US labs are achieving impressive results in driving up the performance of

Nb3Sn conductor in various demonstrator magnets.

Sticking with accelerators, this issue also lays out the possible paths towards a high-energy muon collider – long considered a dream machine for precision and discovery, but devilishly difficult in its details. We also describe the rapid progress being made at synchrotron X-ray sources, arguably the most significant application of accelerator science in recent decades, towards understanding the molecular structure of the SARS-CoV-2 virus. The importance of accelerators for neutron science is a theme of the Viewpoint article, and, in addition to the Courier’s regular coverage of the news, conferences and reviews, this issue includes reports on how high-energy physicists are responding to the COVID-19 pandemic.

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EDITOR: MATTHEW CHALMERS, CERN DIGITAL EDITION CREATED BY IOP PUBLISHING The path to a muon collider  Fine structure in antihydrogen  Reacting to COVID-19

CCMayJun20_Cover_v7.indd 1 24/04/2020 10:25 CERNCOURIER www. V o l u m e 6 0 N u m b e r 3 M a y /J u n e 2 0 2 0 CAEN Electronic Instrumentation CERNCOURIER.COM IN THIS ISSUE V o l u m e 60 N u m b e r 3 m a y /J u N e 2 02 0 FERS-5200 Front-End Readout System A distributed and easy-scalable platform for the readout of large detector arrays X Wu/POLAR CERN-PHOTO-202004-054-3 Av VerdensAv Gang/NTB Scanpix

High-energy ventilator The particle physicists bringing POL A R-2 What gamma-ray polarisation Rolf Widerøe Kurt Hübner reviews a new • Compact Front-End cards (FERS units) tailored for the readout of detector expertise to the fight against coronavirus.8 can tell us about astrophysics. 12 biography of a giant of accelerator physics. 53 different detectors (SiPM, MA-PMTs, Gas Tubes, Si detectors, …) • FERS Unit as a standalone readout system or the basic brick of your NeWS PeoPle experiment ANALYSIS ENERGY FRONTIERS FIELD NOTES CAREERS OBITUARIES • One Concentrator Board to readout up to 8.192 channels HL-LHC quadrupoles Additional Higgs bosons Circular colliders eye Opening doors Alvin Tollestrup • Multiple , thru one or more Concentrators, are easily tested • Special report elude ATLAS • First Higgs self-coupling with a particle- 1924–2020 • Marcello FERS on COVID-19 Strategy sight of top-quark mass Quark Matter in Cresti 1928–2020 Synchronized by Optical Link • • physics PhD update postponed running • ALICE extends Wuhan • Cosmologists Transferable skills • Tatiana Fabergé • Spectroscopy, Counting and Timing acquisition modes • ALPHA on antihydrogen quenching studies meet quantum theorists make particle-physics 1930–2020 • Robert • Flavour anomalies • New SMOG on the • German–Armenian PhDs highly sought Klapisch 1932–2020. 63 • 64-channel FERS unit for the readout of SiPM AVAILABLE NOW persist • POLAR-2. 7 horizon. 17 internship. 23 after by industry. 55

From small Systems to Large experiments! FeaTureS N V Mokhov N V Mokhov BIOPHYSICS MAGNETS ACCELERATORS Synchrotrons on the Taming the Sketching out a coronavirus frontline superconductors muon collider The impressive progress of tomorrow Muon colliders are being made by Accelerator magnets receiving renewed D Owen/Diamond Light Source Light Owen/Diamond D synchrotron X-ray for the HL-LHC are attention as a means to facilities to solve also a springboard to precision at the energy the structure of future fundamental frontier. 41 www.caen.it SARS-CoV-2. 29 exploration. 34 Small details… Great differences oPINIoN DeParTmeNTS Scalable Concentrator with Multiple FERS System Synchronized by Optical Link VIEWPOINT REVIEWS FROM THE EDITOR 5 Bridging Europe’s A unique exercise in NEWS DIGEST 15 M Brice/CERN M neutron gap scientific diplomacy APPOINTMENTS 57 The recent closure of • ITER: The Giant Fusion & AWARDS reactors means making Reactor Obsessed by • RECRUITMENT 58 the most of existing a Dream: The Physicist On the cover: Composite facilities, says Helmut Rolf Widerøe. 51 Cu/Nb3Sn multi-filamentary BACKGROUND 66 Schober. 49 strands (1 mm diameter) for DT5202 DT5215 A5202 ASICs WEEROC new accelerator magnets. 34 Desktop 64 Channel CITIROC Concentrator Board for FERS-5200 64 Channel CITIROC unit programmable analog and unit for FERS-5200 for FERS-5200 mixed front-end CERN COURIER MAY/JUNE 2020 3

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Accelerating science – and medicine S Hertzog/CERN wo dipole magnets, currently hooked up to test rigs in CERN’s SM18 facility, are soon to make history. Sched- T uled to be lowered into the LHC tunnel later this year as part of the High-Luminosity LHC (HL-LHC), they will be the first operational accelerator magnets made from the super-

conducting compound niobium-tin (Nb3Sn). The 5.5 m-long magnets will be positioned at Point 7, where they will make Matthew space to allow t he installat ion of a collimator to mop up off- Chalmers trajectory particles. Without this assembly, the higher beam Editor intensities at the HL-LHC potentially could cause quenches in the downstream dispersion-suppressor regions of the machine.

Next in line for testing are the powerful Nb3Sn quadrupole Milestones Nb3Sn dipole magnets being tested at CERN. magnets that will sit on either side of CMS and ATLAS to reduce the proton beams to even smaller sizes than at present. The achieved 16.4 T in the centre of a short “enhanced racetrack task is split between CERN, which is building eight 7.2 m-long model coil”. In June 2019, a short “cos-theta” dipole magnet quadrupoles, and Fermilab, Brookhaven and Berkeley in the US, reached a bore field of 14.1 T a t 4.5 K at Fermilab. These and the which opted to build eight pairs of 4.2 m versions. Following recent HL-LHC milestones bode well for the future of the field. initial tests of the 11 T dipole magnets at CERN last year, the first HL-LHC quadrupole magnet has recently been tested suc- COVID-19 c e ss f u l ly at Bro ok h ave n, sust a i n i ng a fie ld g r ad ie nt of a rou nd In terms of scientific output, synchrotron X-ray sources are 130 T/m and reaching a peak-field of 11.4 T at the conductor (p7). arguably the most significant application of accelerator sci- As this month’s cover feature explains (p34), the demonstra- ence in recent decades, serving thousands of users across a

tion of Nb3Sn magnet technology for the HL-LHC is also a step- v ast r a nge of topics – i n pa r t ic ula r molec ula r biolog y. In one ping stone to future hadron colliders. The LHC’s cutting-edge of several reports in this issue relating to COVID-19, a team niobium-titanium accelerator magnets enabled physicists to at the UK’s Diamond Light Source is rapidly uncovering the reach the collision energies needed to discover the Higgs boson, structure of the SARS-CoV-2 virus; studies that would have b ut t o e x pl or e n a t u r e a t s i g n i fic a nt l y h i g h e r e n e r g i e s a m a t e rial t a k e n s e v e r a l y e a r s w it h c o n v e nt io n a l l a b -b a s e d X-r a y s o u r c e s

t h a t c a n pr o v i d e h i g h e r fie l d s i s r e q u i r e d. Nb 3Sn is so far the only can now be done in a matter of days (p29). Accelerators are also conductor that experts are confident is capable of sustaining v it a l for s u s t a i n i n g E u r o p e’s n e ut r o n-s c i e n c e pr o g r a m m e – a s The Nb3Sn such fields (up to 16 T) – the baseline field of the dipoles for the argued in this month’s Viewpoint (p49). magnet h a d r o n–h a d r o n m o d e o f t h e pr o p o s e d F ut u r e C i r c u l a r C ol l id e r This accelerator-themed issue was meant to be distributed

technology for (FCC). The Nb3Sn programme is also relevant for a future muon at the 2020 International Particle Accelerator Conference at the HL-LHC is collider, featured on p41 of this issue. GANIL, France, which, though cancelled, may take place in a also a stepping CERN and the US labs are achieving impressive results in virtual format due to the global COVID-19 situation. On this driving up the performance of Nb Sn conductor in various note, with almost all laboratories involved in the HL-LHC stone to 3 Vacuum solutions demonstrator magnets. In 2018, a large-aperture dipole at currently in teleworking mode, there could be some delays future hadron CERN called FRESCA2 attained a record field of 14.6 T, while, in the project schedule. But the decades-long technological colliders earlier this year, CERN, in the framework of the FCC study, march towards higher energies continues to advance.

from a single source Reporting on international high-energy physics CERN Courier is distributed Editor Laboratory correspondents INFN Antonella Varaschin UK STFC Jane Binks Technical illustrator General distribution to governments, institutes Matthew Chalmers Argonne National Jefferson Laboratory SLAC National Accelerator Alison Tovey Courrier Adressage, CERN, Pfei er Vacuum is proud to have been a supplier of innovative and customized vacuum solutions to the particle accelerator and laboratories affiliated Associate editor Laboratory Tom LeCompte Kandice Carter Laboratory Melinda Baker Advertising sales 1211 Geneva 23, Switzerland; with CERN, and to Mark Rayner Brookhaven National JINR Dubna B Starchenko SNOLAB Samantha Kuula Tom Houlden e-mail courrier- community for more than 50 years. Our complete product portfolio for vacuum technology, our focus on competent and individual subscribers. Archive contributor Laboratory Achim Franz KEK National Laboratory TRIUMF Laboratory Recruitment sales adressage@cern.ch specialized advice supported by robust and reliable service, makes Pfei er Vacuum the partner of choice for the analytical It is published six times Peggie Rimmer Cornell University Hajime Hikino Marcello Pavan Chris Thomas per year. The views Astrowatch contributor D G Cassel Lawrence Berkeley Advertisement Published by CERN, 1211 and research communities worldwide. expressed are not Merlin Kole DESY Laboratory Laboratory Spencer K lei n Produced for CERN by production Kat ie Gr a ha m Geneva 23, Switzerland necessarily those of the E-mail Till Mundzeck Los Alamos National Lab IOP Publishing Ltd Marketing and Tel +41 (0) 22 767 61 11 CERN management. [email protected] Enrico Fermi Centre Rajan Gupta Temple Circus, Temple circulation Laura Gillham ■ Pumps for vacuum generation down to UHV Guido Piragino NCSL Ken K i nger y Way, Bristol BS1 6HG, UK Printed by Warners ■ Vacuum measurement and analysis equipment Advisory board Fermilab Kurt Nikhef Robert Fleischer Tel +44 (0)117 929 7481 Advertising (Midlands) plc, Bourne, Peter Jenni Riesselmann Novosibirsk Institute Tel +44 (0)117 930 1026 Lincolnshire, UK ■ Leak detectors and integrity test systems Christine Sutton Forschungszentrum S Eidelman Head of Media Jo Allen (for UK/Europe display ■ Vacuum chambers and components Claude Amsler Jülich Markus Buescher Orsay Laboratory Head of Media advertising) or © 2020 CERN Philippe Bloch GSI Darmstadt I Peter Anne-Marie Lutz Business Development +44 (0)117 930 1164 (for ISSN 0304-288X ■ Pumping stations and customized solutions Roger Forty IHEP, Beijing Lijun Guo PSI Laboratory P-R Kettle Ed Jost recruitment advertising); Mike Lamont IHEP, Serpukhov Saclay Laboratory Production editor e-mail sales@ Joac h i m Kopp Yu Ryabov Elisabeth Locci Ruth Leopold cerncourier.com Are you looking for a perfect vacuum solution? Please contact us: Pfeiffer Vacuum (Schweiz) AG · T +41 44 444 22 55 · F +41 44 444 22 66 · [email protected] www.pfeiffer-vacuum.com CERN COURIER MAY/JUNE 2020 5

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1000mm/s Linear Actuators AccelerAtors Magnetically-coupled or bellows sealed options HL-LHC quadrupole successfully tested Brookhaven National Laboratory National Brookhaven A superconducting quadrupole magnet mag nets are being produced by CERN. for the high-luminosity LHC (HL-LHC) “We’ve demonstrated that this first has been tested in the US, attaining a quadrupole magnet behaves success- conductor peak field of 11.4 T – a record fully and according to design, based for a focusing magnet ready for instal- on the multiyear development effort lation in an accelerator. The 4.2 m-long, made possible by DOE [Department 150 m m-si ng le-ap er t ure de v ice i s ba se d of Energy] investments in this new on the superconductor niobium-tin technology,” said Fermilab’s Giorgio

(Nb3Sn) a n d i s o n e o f s e v e r a l q u a d r up ol e s Apollinari, head of the US Accelerator being built by US labs and CERN for the Upgrade Project in a Fermilab press HL-LHC, where they will reduce the size release. “It’s a cutting-edge magnet,” of the proton beams within the ATLAS added Kathleen Amm, Brookhaven’s and CMS experiments to produce a higher representat ive for t he project. luminosity. The result follows success- ful tests carried out last year at CERN of Dipole tests at CERN

the first accelerator-ready Nb3Sn dipole In addition to stronger focusing mag- magnet, and the milestones are soon to be nets, the HL-LHC requires new dipole fol l o w e d b y t e s t s o f o t h e r 7.2 m a n d 4.2 m magnets positioned on either side of a q u a d r u p ol e m a g n e t s a t C E R N a n d t h e US. collimator that corrects off-momentum protons in the high-intensity beam. To Collaboration gain the required space in the magnetic

“This copious harvest comes after sig- lattice, Nb3Sn dipole magnets of shorter nificant recent R&D on niobium-tin length and higher field than the cur- superconducting magnet technology rent LHC dipole magnets are needed. and is the best answer to the question if In July 2019 the CERN magnet group HL-LHC is on time: it is,” says HL-LHC successfully tested a full-length, 5.5 m, project leader Lucio Rossi of CERN. 60 m m-t w i n-a p e r t u r e d i p ol e m a g n e t a n d Speaking of the US quadrupole test, he High field plasma in the ITER fusion experiment – it achieved a nominal bore field of 11.2 T at c o nt i nue d: “T h i s f u l l-l e n g t h, a c c e le r a- The advanced is more challenging than Nb-Ti to work 1.9 K (corresponding to a conductor peak

tor-ready magnet performance record quadrupole w it h. O n c e for m e d, t h e N b 3Sn compound field of 11.8 T). CERN and the US labs are is a real textbook case for international magnet being b e c o m e s br it t l e a n d s t r a i n-s e n s it i v e a n d a l s o a c h i e v i n g i m pr e s s i v e r e s u l t s i n d r i v-

collaboration: since the very beginning prepared for a test therefore much harder than niobium- ing the performance of Nb3Sn conductors the three US labs and CERN teamed up at Brookhaven titanium alloy to process into cables to t o m u c h h i g h e r fie l d s, a s w o u l d b e n e ed a n d m a n a g e d t o h a v e a c o m m o n a n d v e r y National be wound with the accuracy required to for future hadron colliders beyond the synergic R&D, particularly for the quad- Laboratory. achieve the performance and field quality LHC (see p34). rupole magnet that is the cornerstone of of state-of-the-art accelerator magnets. Before being judged fully operational the upgrade. This has resulted in sub- The purpose of a quadrupole mag- and ready to be installed in the HL-LHC, stant ia l sav ings and improved out put.” net is to produce a field gradient in the the US-based quadrupole magnets and The current LHC dipole magnets, radial direction with respect to the beam, the CERN-based dipole magnets must which have been tested to a bore-field allowing charged-particle beams to be connected in pairs. Each magnet in a o f 8.3 T and are currently operated at 7.7 T be focused. Researchers at Fermilab, pair has the same winding, and differs at 1.9 K for 6.5 TeV operation, are made Brookhaven National Laboratory and only in its mechanical interfaces and from the superconductor niobium- Lawrence Berkeley National Laboratory details of its electrical circuitry. Tests titanium (Nb-Ti). As the transport prop- are to provide a total of 16 quadrupole of the remaining halves of the quadru- erties of Nb-Ti are limited for fields magnets for the interaction regions of pole and dipole pairs were scheduled to Designed in collaboration with Particle Accelerators to provide b e y o n d 10–1 1 T a t 1.9 K, H L-L HC m a g n e t s This is a real the HL-LHC, which is due to operate from take place in the US and at CERN this c a l l for a mo ve to Nb 3Sn, which remains textbook 2027. The recent test was carried out at summer, with the dipole magnet pairs precise, high speed actuation of beamline diagnostics. superconducting for much higher fields. case for Brookhaven in January, when the team to be installed in the LHC tunnel by the Although Nb3Sn has been studied for dec- international operated the 8 tonne quadrupole magnet end of the year. Given that the relevant ades and is already in widespread use in collaboration continuously at a nominal field gradient laboratories are currently in teleworking solenoids for nuclear magnetic resonance of around 130 T/m and a temperature of m o d e d u e t o C OV I D -19, t h i s pl a n m a y h a v e – n o t t o m e nt i o n u n d e r pi n n i n g t h e l a r g e in the 1.9 K for five hours. Eight longer quad- t o b e r e v i e w e d, s a y s R o s s i, w h o a d d s t h a t coils presently being manufactured that accelerator rupole magnets each with an equiva- this is now the high-priority discussion Contact [email protected] for more information will be used to contain and control the domain lent “cold mass” of two US quadrupole w it hin t he HL-LHC project. www.uhvdesign.com CERN COURIER MAY/JUNE 2020 7

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NEWS ANALYSIS NEWS ANALYSIS Covid-19: speCial report Covid-19: speCial report

Physicists develop stripped-down ventilator European strategy update postponed J Fichet/CERN As part of the global response to the further prototyping and deployment During its 197th session, which took place on recommendations. These were due In these has been replaced by a new extraordinary COVID-19 pandemic, a team led by stages. “This is a device that has patient for t he fi rst t i me by v ide o con ference on to be submitted for final approval at exceptional Council session, to be held by videoconfer- physicists and engineers from the LHCb safety as a major priority,” says HEV 19–20 March, the CERN Council addressed an extraordinary session of the CERN circumstances ence on the same date, at which delegates collaboration has proposed a design for collaborator Themis Bowcock of the the impact of the current COVID-19 sit- Council on 25 May in Budapest, Hungary, will discuss how to proceed. a novel ventilator. The High Energy University of Liverpool. “It is aimed uation on the update of the European before being publicly released. it is not the “In these exceptional circumstances it Ventilator (HEV) is based on components at deployment round the world, and in strategy for particle physics (ESPPU). Acknowledging that the COVID-19 out- right time to is not the right time to release the strat- that are simple and cheap to source and, places that do not necessarily have state- The ESPPU got under way in September brea k affects t he ever yday lives of a sig- release the egy, and discussing with various stake- a l t h o u g h t h e s y s t e m n e e d s t o b e v e r i fie d of-the-art facilities.” 2017, when the CERN Council appointed a n i fic a nt f r a c t i o n o f t h e g l o b a l p o p u l a t ion, strategy holders in the Member States will take by medical experts before it can enter use, European Strategy Group (ESG) to organ- the CERN Council has now agreed that it more time,” says Ursula Bassler, presi- in the interests of rapid development the Complementary designs ise the process. Following two years of would not be appropriate to release the dent of the CERN Council. “Even though HEV team has presented the design to The HEV ventilator complements another discussions with the high-energy physics ESG update (and an accompanying delib- this will come as a disappointment to generate feedback. The proposal is one recent proposal initiated by physicists in and related communities (CERN Courier eration document) to a wider audience, nor many physicists after all the effort put of several recent and rapidly developing the Global Argon Dark Matter Collabora- November/December 2019 p8), culmi- for the Council to make any further com- into the ESPPU, everyone can understand, e ffor t s l a u n c h e d b y h i g h- e n e r g y p hysi- tion. The Mechanical Ventilator Milano nating in a week-long drafting session ment on the contents of the documents that in this situation, the process will cists to help combat COVID-19. (MVM) is optimised to permit large-scale in January, the ESG reported convergence for the time being. The Budapest event last longer.” Most people infected with the COVID- production in a short amount of time 19 virus recover without requiring special and at a limited cost, also relying on off- treatment, but in some cases the disease the-shelf components that are readily CERN establishes coronavirus task force can cause severe breathing difficulties available. In contrast to HEV, which aims J Fichet & M Struik/CERN J Fichet and pneumonia. For such patients, the t o c o nt r ol pr e s s u r e b y a l t e r n a t e l y fi l l i n g In March, CERN established a task force Clean hands equipment, to the production of sanitiser availability of ventilators that deliver Prototyping and health-and-safety requirements, and emptying a buffer, the MVM regu- to collect and coordinate ideas from the Benoit Teissandier gel (pictured) and Perspex shields and oxygen to the lungs while removing Jan Buytaert and and the working relationship with local lates the flow of the incoming mixture of 18,000-strong global CERN community prepares sanitiser visors for emergency-response teams. carbon dioxide could be the difference Paula Collins with hospitals. The team is also greatly sup- oxygen and air via electrically controlled to help fight the COVID-19 pandemic. gel in the CERN Another platform, Science Responds between life and death. Even with exist- the HEV prototype ported from other CERN departments, in valves. The proposal stems from a coop- The CERN-against-COVID-19 group chemistry (science-responds.org), led by research- ing suppliers ramping up production, in the LHCb VELO particular for electronic design and the eration of particle- and nuclear-physics (against-covid-19.web.cern.ch) aims to laboratory. ers in the US and loosely modelled on the rapid rise in COVID-19 infections lab at CERN on selection of the best components for gas laboratories and universities in Canada, work closely with experts in healthcare, the HEP Software Foundation, has been is causing a global shortage of ventila- 6 April. manipulation. We were also very encour- Italy and the US, with an initial goal to drug development, epidemiology and established to facilitate interactions t or s. M u l t i pl e e ffor t s a r e t h e r e for e b e i ng aged to find that it was possible in a short produce up to 1000 units in each of the e m e r g e n c y r e s p o n s e t o h e l p e n s u r e e ffe c- between COVID-19 researchers and the mounted by governments, industry and space of time to set up an online chat three countries while the interim cer- tive and well-coordinated action from broader science community. a c a d e m i a t o m e e t t h e d e m a n d, w it h fi r m s group of experienced anaesthesiologists tification process is ongoing. high-energy physicists. The laboratory “It’s not about going out there and that normally operate in completely dif- and respiratory experts from Australia, Sharing several common ideas with has also offered its support to the World doing things because we think we know ferent sectors, such as Airbus, Dyson and Belgium, Switzerland and Germany, the MVM principle, but with emphasis Health Organization, with which it has best,” says Beniamino Di Girolamo of General Motors, diverting resources to which sped up the design considerably.” on further reducing the number and had a collaboration agreement since 2011. proposals for ventilators (see previous CERN, who is chair of the CERN-against- the task. specificity of components, another The initiative has attracted a large page), efforts so far range from the use C OV I D -19 t a s k for c e. “B ut a b o ut o ffe r i n g HEV was born out of discussions in the Keeping it simple ventilator design called Project Open number of suggestions at various stages of CERN’s computing resources and 3D our services and waiting to hear from the LHCb VELO group when lead designer The HEV concept comprises electro- Air has been proposed by a team led by of development. In addition to listing printing of components for medical experts as to how we may be able to help.” Jan Buytaert of CERN realised that the valves, a 10 litre buffer container, a particle physicists at the Laboratory S Hertzog/CERN S systems which are routinely used to sup- pressure regulator and several pressure of Instrumentation and Experimental Empty spaces, but ply and control gas at desired tempera- and flow sensors. Embedded compo- Particles Physics in Portugal. All designs tures and pressures in particle-physics nents – currently Arduino and Rasbperry are evolving quickly and require further physics continues Struik/CERNM detectors are well matched to the tech- Pi – are being used to meet portability development before they can be deployed niques required to build and operate a requirements. The unit’s functionality is in hospitals. As the Courier went to press, CERN was ventilator. The driving pressure of ven- comprehensive enough to provide long- “It i s d i ffic u l t t o c o n c e i v e a pr oj e c t t ha about to enter its sixth week of shut- tilators – which must be able to han- term support to patients in the initial goes all the way and includes all the bells down in line with Stage 3 of the epidemic-

dle situations of rapidly changing lung or recovery phases, freeing up high-end and whistles needed to get it into the preparedness plan. Since 20 March, S Hertzog/CERN behaviour and potential collapse – is a machines for the most serious intensive hospital, but this is our firm goal,” says activities at CERN have largely been crucial factor for patient outcomes. The care, explains Collins: “It incorporates Collins. “After one week we had a func- limited to those essential for safety and

HEV team therefore aimed to produce a touchscreen control that is intuitive to tioning demonstrator, after two weeks security, with approximately 300 people Hertzog/CERNS p a t i e nt-s a fe t y-fi r s t d e s i g n w it h pr e c i se u s e for q u a l i fie d m e d ic a l p e r s o n n e l, e ven we tested on a medical mechanical lung, working on site as opposed to several pressure control, providing internation- Systems in if they are not specialists in ventilator and we are now prototyping under clin- thousand during normal times. Also, ally recommended operation modes. use, and it includes extensive monitor- ical supervision. We find ourselves in a having carefully reviewed the feasibility As the HEV team comprises physi- particle- ing and failsafe mechanisms based on unique and urgent situation where there of running its diverse student and trainee cists, rather than medics, it was vital physics CERN’s long experience in this area, with are many proposals on the market, but programmes in light of the evolution of Silent CERN (clockwise from top left) The CERN Control Centre, the Theory Department, Restaurant 1 and to get the relevant input from the very detectors are o n l i n e t r a i n i n g t o b e d e v e l o p e d.” T h e fi r s t we don’t know now which ones will in the COVID-19 pandemic, CERN has post- Building 40, captured during the current lock-down phase. start, explains HEV collaborator Paula well matched to stage of prototyping, which was achieved t h e e n d m a k e a d i ffe r e n c e, s o e v e r y t h i ng poned the start dates for students and Collins of CERN. “Here we have bene- the techniques at CERN on 27 March, demonstrated that that could be viable should be pursued.” traineeships, and was forced to cancel its numerous measures have been put in place large LHC collaborations, remote working flagship summer-student programmes is not so unusual. However, many activities fited enormously from the experience required to the HEV principle is sound and allows the to help with continuity. Video conferences and knowledge of CERN’s HSE [Occupa- ventilator to operate within the required Further reading for this year. have become the new norm, with high lev- relating to the experiment upgrades and tional Health & Safety and Environmental build and ranges of pressure and time. The support J Buytaert et al. 2020 arXiv:2004.00534. While CERN’s corridors and cafeterias els of participation being witnessed across other work taking place on CERN’s accel- Protection] group for medical advice, operate a of clinicians and international organ- C Galbiati et al. 2020 arXiv:2003.10405. lie almost empty, the vast majority of experiments and departments. For many erator complex during long-shutdown two conformity with applicable legislation ventilator isations is now being harnessed for A Pereira et al. 2020 arXiv:2004.00310. personnel and users are teleworking, and physicists working on data analysis in the have temporarily been put on hold.

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NEWS ANALYSIS NEWS ANALYSIS

A ntim Atter distributions as a function of the invari- This has led physicists to speculate that We as a the decays of beauty baryons, which also 2 ant mass squared (q ) of the muon pair is t h e t w o e ffe c t s c o u l d b e c a u s e d b y t h e same community depend on b → s transitions, to bear on ALPHA sheds light on antihydrogen’s fine structure of particular interest because it does not new physics, with models involving lepto- have been the subject. depend heavily on hadronic modelling quarks or new gauge bosons in principle “We have not seen evidence of new Source: eagerly The ALPHA collaboration at CERN has holds up in both matter and antimatter, uncertainties. able to accommodate both sets of anom- physics, but neither were the B physics 1S → 2P reported the first measurements of c,d c± Nature a nd prob es a sp e c t s of a nt i mat ter i nter- Potentially anomalous behaviour in an alies (CERN Courier May/June 2019 p33). waiting for this anomalies ruled out,” says Zupan of the ′ fine-structure effects and the Lamb 1Sc,d → 2Pf± a c t i o n – s u c h a s t h e L a m b s h i f t – t h a t w e angular variable called P5 came to light An update on RK based on additional measurement LHCb result. “The wait for the clear evi- s h i f t i n a nt i h yd r o g e n a t o m s. T h e r e s u l t s, h a v e l o n g l o o k e d for w a rd t o a d d r e s s i n g,” in 2013, when LHCb reported a 3.7σ local Run-2 data is hotly anticipated, and the and LHCb dence of new physics continues.” 2 published in Nature in February, bring 1Sd → 2Pc– s a y s A L PH A s p o k e s p e r s o n Je ff r e y H a n g s t. deviation with respect to the SM in one q collaboration is also planning to add data has not f u r t h e r s c r ut i n y t o c o m p a r i s o n s b e t w e e n The seminal measurements of anti- bin, based on 1 fb–1 of data. In 2015, a global from 2017–2018 to the B0 → K*0μ+μ– angu- Further reading 1Sd → 2Pf– disappointed antimatter and ordinary matter, which, hydrogen’s spectral structure that are fit of different angular distributions of lar analysis. LHCb also recently brought LHCb Collab. 2020 arXiv:2003.04831. 0 *0 + – if found to behave differently, would average n o w p o s s i ble fol lo w m or e t h a n 30 ye a r s B → K μ μ decays using the total Run-1 c h a l le n g e C P T s y m m e t r y a n d s h a k e t h e of effort by the low-energy antimat- data sample of 3 fb–1 rea ffi r me d t he puz- foundations of the Standard Model. –80 –40 04080 ter community at CERN (CERN Courier zle, showing discrepancies of 3.4σ (later In 1947, US physicist Willis Lamb and March 2018 p30). The first antihydro- reduced to 3.0σ when using new theory [fres(exp) – fres(th)]/fres(th) (ppb) his colleagues observed an incredibly gen atoms were observed at CERN’s calculations). In 2016, the Belle experi- small shift in the n = 2 energy levels of LEAR facility in 1995 and, in 2002, the ment at KEK in Japan performed its own hydrogen in a vacuum. Under traditional In line The splitting of the n = 2 energy level ATHENA and ATRAP collaborations pro- angular analysis of this decay using physics theories of the day, namely the The measured o f h yd r o g e n i s a s e p a r a t io n b e t w e e n t h e duced cold (trappable) antihydrogen at data from electron–positron collisions

D i r a c e q u a t io n, t h e s e s t a t e s s h o u l d h a v e frequencies for the 2P3/2 and 2P1/2 levels in the absence of the AD, opening the way to precision and found a small (2.1σ) deviation in the the same energy and the Lamb shift 1S–2P transitions a magnetic field, and is caused by the measurements of antihydrogen’s atomic same direction and in the same q2 region shouldn’t exist. The discovery spurred in antihydrogen, interaction between the electron’s spin s p e c t r a. I n a d d it i o n t o s p e c t r a l m e a s u r e- as the LHCb anomaly.

t h e d e v e l o p m e nt o f q u a nt u m e l e c t r o d y- fres(exp), compared and the orbital momentum. The classic m e nt s, t h e c h a r g e-t o -m a s s r a t io s for t h e The latest LHCb result includes addi- namics (QED), which explains the dis- with those Lamb shift is the splitting between the pr o t o n a n d a nt i pr o t o n h a v e b e e n s h o w n tional Run-2 data collected during 2016,

crepancy as being due to interactions theoretically 2S1/2 and 2P 1/2 levels, also in t he absence to agree to 69 parts per trillion by the corresponding to a total integrated lumi- between the atom’s constituents with expected for of a magnetic field, and is the result of the BASE experiment, and the antipro- nosity of 4.7 fb–1. It shows that the local ′ 2 vacuum-energy fluctuations, and won hydrogen, fres(th), effect on the electron of quantum fluctu- ton-to-electron mass ratio has been tension of P5 in two q bins between 4 L a m b t h e No b e l P r i z e i n P h y s i c s i n 1955. with error bars at ions associated w it h v ir t ual photons. measured to agree with its proton and 8 GeV2/c4 reduces from 2.8 and 3.0σ, T h e A L PH A t e a m c r e a t e s a nt i h yd r o g e n corresponding to In its new study, the ALPHA team counterpart to a level of 0.8 parts per as observed in the previous analysis, to 2.5 atoms by binding antiprotons delivered 1σ. All are consistent determined the fine-structure split- billion by the ASACUSA experiment. and 2.9σ, but LHCb notes t hat a global fit by CERN’s Antiproton Decelerator (AD) with hydrogen, and ting and the Lamb shift by inducing The newly completed ELENA facility to several angular observables increases with positrons. The antiatoms are then their average gives transitions between the lowest (n = 1) at the AD will increase the number of the overall tension with the SM from 3.0 c o n fi n e d i n a m a g n e t i c t r a p i n a n u ltra- a combined test of energy level of antihydrogen and the available antiprotons by up to two orders to 3.3σ. T h e r e s u l t s o f t h e fit a l s o fi n d bet-

high vacuum, and illuminated with a CPT invariance at 2P3/2 and 2P1/2 levels in the presence of of magnitude. ter overall agreement with predictions of l a s e r t o m e a s u r e t h e i r s p e c t r a l r e s p o n s e. the level of 16 parts a 1 T magnetic field. Using the value of Next for the ALPHA team is chill- new-physics models that contain addi- This technique enables the measurement per billion. the frequency of a previously measured ing large samples of antihydrogen tional vector or axial-vector contributions. of known quantum effects such as the fine transition (1S–2S), the team was able to using state-of-the-art laser cooling However, the collaboration also makes it s t r u c t u r e a n d t h e L a m b s h i f t, w h ic h h a v e infer the values of the fine-structure techniques. “These techniques will clear that the discrepancy could be due to n o w b e e n m e a s u r e d i n t h e a nt i hydrogen s pl it t i n g a n d t h e L a m b s h i f t. T h e r e s u l t s transform antimatter studies and will a n u n e x p e c t e d l y l a r g e h a d r o n ic e ffe c t t h a t atom for the first time. The ALPHA team w e r e fo u n d t o b e c o n s i s t e nt w it h t h e or e t- allow unprecedentedly high-precision is not accounted for in the SM predictions. pr e v i o u s l y u s e d t h i s a p pr o a c h t o m e a s u r e ical predictions of the splittings in nor- compa r i son s b et we en m at ter a nd a nt i- “We as a community have been eagerly o t h e r q u a nt u m e ffe c t s i n a nt i h yd r o g e n, mal hydrogen, within the experimental mat ter,” says Hangst. waiting for this measurement and LHCb the most recent being a measurement u n c e r t a i nt ie s o f 2% for t h e fi n e-s t r u c t u r e has not disappointed,” says theorist Jure of the Lyman–alpha (1S–2P) transition s pl it t i n g a n d 1 1% for t h e L a m b s h i f t. “T h e Further reading Zupan of the University of Cincinnati. “The in 2018 (CERN Courier October 2018 p9). w or k c o n fi r m s t h a t a k e y p or t i o n o fQED ALPHA Collab. 2020 Nature 578 375. new measurements have moved closer to the SM predictions in the angular observ- LHCb FlAvour physics w it h t h e St a n d a r d M o d e l (S M) pr e d i c t i o n, 1.0 a bl e s s o t h a t t h e c o m bi n e d s i g n i fic a n c e o f A noma lies persist in Sim Run 1 2016 though, at 3.3σ, more data are needed to the excess remained essentially the same. SM from DHMV confir m or r ule out t he effect. It is thus becoming even more important B-meson decays 0.5 The B0 → K*0μ+μ– decay is a promising to understand and scrutinise the SM pre- system with which to explore physics dictions and claimed theory errors.” The LHCb collaboration has confirmed beyond the SM. A flavour-changing The latest result makes LHCb’s con- P5ʹ 0 previous hints of odd behaviour in the neutral-current process, it involves a tinued measurements of lepton-flavour way B mesons decay into a K * and a pair quark transition (b → s) that is forbid- universality even more important, says –0.5 of muons, bringing fresh intrigue to the den at the lowest perturbative order in Zupan. In recent years, LHCb has found

pattern of flavour anomalies that has J/ ψ (1S) t h e S M, a n d t h e r e for e o c c u r s o n l y a r o u n d that the ratio of the rates of muonic and ψ (2S) emerged during the past few years. At –1.0 once for every million B decays. The electronic B decays departs from the SM a seminar at CERN on 10 March, Eluned 0510 15 decay proceeds instead via higher-order prediction, suggesting a violation of the Smith of RWTH Aachen University pre- penguin and box processes, which are key SM principle of lepton-flavour uni- q2 (GeV2/c4) sented an updated analysis of the angular sensitive to the presence of new, heav y versality. Though not individually sta- 0 *0 + – ′ d i s t r i b ut i o n s o f B → K μ μ d e c a y s b a s e d Angular puzzle The distribution of the angular variable P5 as a particles. Such particles would enter in t ist ica l ly sig nificant, t he measurements on around twice as many events as used for function of the mass squared of the muon pair, q2. The results from competing processes and could signifi- are theoretically very clean, and the most the collaboration’s previous measurement Run 1 (red), those from the additional 2016 dataset only (purple), c a nt l y c h a n g e t h e B 0 → K*0μ+μ– d e c a y r a t e striking departure – in the variable known

(CERN Courier May 2015 p8). The result and those from both LHCb datasets (grey) are shown, along with a n d t h e a n g u l a r d i s t r i b ut io n o f it s fi n a l- as RK – concerns B decays that proceed via s r e v e a l s a m i l d i n c r e a s e i n o v e r a l l t e n s io n the SM predictions (orange). state particles. Measuring angular the same b → s transition as B0 → K*0μ+μ–.

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NEWS ANALYSIS HIGH PRECISION POWER SUPPLIES

AstrowAtch HIGH VOLTAGE. EXACTLY. Gamma-ray polarisation sharpens multi-messenger astrophysics OUT NOW Recent years have seen the dawn of short time intervals, a strong hint of multi-messenger astrophysics. Perhaps high polarisation is found with a rapidly t h e m o s t s i g n i fic a nt c o nt r i b ut or t o t h is changing polarisation angle during the new era was the 2017 detection of gravi- 161203A GRB event. This rapid evolution of the WITH ONBOARD tational waves (GWs) in coincidence with polarisation angle, which is yet to be a bright electromagnetic phenomenon, 161217C explained by the theoretical commu- a gamma-ray burst (GRB). GRBs consist n it y, smea rs out t he pola r isat ion when 161218A PYTHON SCRIPTING o f i nt e n s e b u r s t s o f g a m m a r a y s w h i c h, looking at the full GRB. In order to fully for periods ranging from hundreds of 161218B understand t he evolut ion, wh ic h could milliseconds to hundreds of seconds, give hints of an evolution of a magnetic outshine any other source in the uni- 161229A fie l d, fi n e r t i m e-bi n n i n g a n d m orepr- verse. Although the first such event was 170101A cise measurements are needed, which spotted back in 1967, and t y pically one require more statistics. GR B i s d e t e c t e d e v e r y d a y, t h e u n d e rl y- 170101B ing astrophysical processes responsible POL A R-2 170114A remain a mystery. The joint GW–electro- T w o f ut u r e i n s t r u m e nt s c a p a bl e o f pr o - magnetic detection answered several 170127C viding such detailed measurements are questions about the nature of GRBs, but currently being developed. The first, many others remain. 170206A P OL A R-2, i s t h e fol l o w-up o f t h e P OL A R Recently, researchers made the first 170207A mission and was recently recommended attempts to add gamma-ray polarisation to become a CERN-recognised exper- into the mix. If successful, this could 170210A iment. POLAR-2 will be an order of e n a bl e t h e n e x t s t e p for w a r d w it h i n t h e magnitude more sensitive (due to larger 170305A multi-messenger field. statistics and lower systematics) than So far, three photon parameters – 170320A it s pr e d e c e s s or a n d t h e r e for e s h o u l d b e arrival time, direction and energy – 0420 0 60 80 100 able to answer most of the questions have been measured extensively for PD(%) r a i s e d b y t h e r e c e nt P OL A R r e s u l t s. T h e a range of different objects within experiment will also play an important astrophysics. Yet, despite the wealth Ne w t o ol Probability distributions for the likely degree of r ol e i n d e t e c t i n g e x t r e m e l y w e a k GR B s, of information it contains, the photon polarisation (PD) of various GRBs inferred from POLAR data, such as those expected from GW events. NEW polarisation has been neglected. X-ray indicating that the emission is lowly polarised or unpolarised for POLAR-2, which will be launched in or g a m m a-r a y flu x e s e m it t e d b y c h a r g ed the vast majority of events. This would imply that magnetic fields 2024 to the under-construction China particles within strong magnetic fields are not important in these bright explosions, but detailed studies Space Station, could well be followed by EDIT your python script directly on browser or locally with a r e h i g h l y p ol a r i s e d, w h i l e t h o s e e m it- paint a more complicated picture. a s i m i l a r b ut s l i g ht l y s m a l l e r i n s t r u m e nt access to all hardware parameters ted by thermal processes are typically called LEAP, which recently progressed unpolarised. Polarisation therefore urements are further complicated by the to the final stage of a NASA selection allows researchers to easily identify n e e d t o p e r for m t h e m a b o v e t h e a t m o s- pro c e s s. I f s uc c e s s f u l, LE A P wou ld joi n UPLOAD and start the script directly on iCS capable device the dominant emission mechanism for phere on satellites, which complicates POLAR-2 in 2025 in orbit on the Inter- a particular source. GRBs are one such t he detector desig n sig nificant ly. national Space Station. CREATE your own visualisation easily in HTML / Javascript / CSS s o u rc e, s i nc e a c on s e n s u s on w he re t he Recent progress has shown that, Apart from dedicated GRB polarime- gamma rays actually originate from is although challenging, polarisation t e r s, pr o g r e s s i s a l s o b e i n g m a d e a t o t h e r still missing. measurements are possible. The most upcoming instruments such as NASA’s THOUSANDS OF APPLICATIONS POSSIBLE recent example came from the POLAR I m a g i n g X-r a y P ol a r i m e t r y E x pl or e r a n d Data logging, event driven voltage channel control, testing, external control of voltage (by temperature changes), block rampup. Difficult measurements mission, a Swiss, Polish and Chinese China-ESA’s enhanced X-ray Timing Start easily with the iseg datalogger example, which stores measured values directly on USB flash drive. The reason that polarisation has not experiment fully dedicated to meas- a n d P ol a r i m e t r y m i s s i o n, w h ic h a i m t o been measured in great detail is related uring the polarisation of GRBs, which perform the first detailed polarisation Register now for BETA version by sending an E-Mail to: [email protected] t o t h e d i ffic u l t y o f p e r for m i n g t h e m eas- took data from September 2016 to April measurements of a range of astrophysi- urements. To measure the polarisation 2017. The team behind POLAR, which c a l o bj e c t s i n t h e X-r a y r e g i o n. W h i l e t h e runs on: MMS / Mpod multichannel Low and High Voltage of an incoming photon, details of the was launched to space in 2016 attached first measurements from POLAR have supplies with CC24 Controller card SHR labratory High Voltage secondary products produced as it inter- to a module for the China Space Sta- been published recently, and more are iCSmini2 Source-Measure-Unit ac t s i n a detec tor need to be measured. tion, recently published its first results. expected soon, the 2020s should see controller box W it h g a m m a r a y s, for e x a m pl e, t h e a n g l e The 2020s Though they indicate that the emis- t he st a r t of a ne w t y pe of ast rophysics, at which the gamma ray scatters in the shou ld s e e sion from GRBs is likely unpolarised, which adds yet another parameter to detector is related to its polarisation the story appears to be more complex. multi-messenger exploration. vector. This means that, in addition to t he st a r t of a For example, the polarisation is found d e t e c t i n g t h e p h o t o n, r e s e a r c h e r s n e e d ne w t y p e of to be low when looking at the full GRB Further reading to study its subsequent path. Such meas- astrophysics emission, but when studying it over S Zhang et al. 2019 Nat. Astron. 3 258.

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missing energ y recoiling ag ainst collider searc h for dyons using a Xi excitations puzzle et al. t he t wo clean lepton t rac ks. subdetector system consist ing The LHCb collaboration has No e xcess of events w as found, of almost a tonne of aluminium obser ved a system of t hree nar row EHT/JY KimEHT/JY yielding preliminary sensitivity (arXiv:2002.00861). The 2400 pea ks in t he inv ariant mass of + – to t he coupling g′ in t he so-called bars were exposed to 13 TeV ΛcK pairs, inter preted as t he 0 Lμ–L τ e x tension of t he SM. This proton–proton collisions at the decays of new excited Ξc (csd) model, wherein t he Z′ couples on ly LHC bet ween 2015 and 2017, and states at 2923, 2939 and 2965 MeV to muon and tau-lepton flavoured t hen scanned using a SQUID (arXiv:2003.13649, submitted to + Event Horizon Telescope image of a jet SM par t icles and t he dark sector, mag netometer to look for t he Phys. Rev. Lett.). The Λc bar yons produced by a supermassive black hole. also has the potential to explain presence of t rapped mag net ic were reconstructed in their + – – + 0 anomalies in b → sμ μ decays c harge belong ing to dyons. decays into pK π . The Ξc(2923) 0 Black-hole sightings repor ted by LHCb (CERN Courier The researchers ruled out the and Ξc(2939) are obser ved for t he 0 The world took note last April May/June 2019 p33) and t he muon e x istence of dyons t hat car r y a first time. TheΞ c(2965) is close when the Event Horizon Telescope g-2 anomaly, claims t he team magnetic charge ranging up to six to a prev iously k now n state, t he 0 collaboration published the (Phys. Rev. Lett. 124 141801). units of a f undamental mag net ic Ξc(2970) , but its measured mass first ever image of a blac k hole. c harge (t he Dirac c harge) and an and w idt h differ sig nificant ly from The team has now used t heir Neutron STAR measurements elec t r ic c harge up to 200 t imes t he e x ist ing Belle and BA BA R results. Discovery science - Magnet UHV chamber global network of telescopes The STAR collaboration at elect ron’s c harge, for dyons w it h a Further studies are required to to image a jet produced by a Brookhaven’s Relativistic Heavy- mass bet ween 830 and 3180 G eV. clarify the situation.

supermassive black hole, blazar Ion Collider has measured the VECC 3C 279, in hit her to unseen binding of t he lightest st range New measure of neutron EDM detail (pictured), revealing an nucleus to be stronger than The nEDM collaborat ion at t he Paul unexpected twisted shape and previously thought (Nat. Phys. 16 Sc her rer Inst it ute in Sw it zerland per pendicular feat ures t hat could 409). Hypertriton is the bound has published t he most sensit ive be inter preted as t he poles of t he state of a tritium nucleus – a measurement so far of t he elect ric accret ion disk. Variat ion obser ved triton – where one neutron dipole moment of t he neut ron over consecut ive days could be has been replaced by a lambda (nEDM), 0.0 ± 1.1 (stat.) ± 0.2 (syst.) due to rotation of the accretion hyperon. STAR measured its × 10–26 e cm, by w atc h ing for sh i f ts in disk and shredding and in fall of binding energy, defined to be t he Lar mor precession frequenc y of material, say t he team (Astron. the mass of its components, a ultracold neutrons proportional to Astrophys. doi: 10.1051/0004- deuteron and a lambda hyperon, an applied elect ric field (Phys. Rev. 6361/202037493). Meanwhile, less the measured mass of the The Superconducting Cyclotron. Lett. 124 081803). A non zero nEDM following up on leads from NASA’s nucleus, to be 0.41 ± 0.12 (stat.) would be ev idence of t he v iolat ion Chandra X-ray Obser v ator y and ± 0.11 (syst.) MeV. Previous Kolkata cyclotron operational of t ime-reversal sy mmet r y, ESA’s X-ray Multi-Mirror Mission, measurements in t he 1970s More than three decades since t herefore also suggest ing t he the Hubble Space Telescope has were consistent w it h zero. The the project began, external v iolat ion of CP, i f CP T sy mmet r y found t he first st rong ev idence for result places constraints on the beam has been sighted at the holds. A s t he nEDM due to CP t he e x istence of an inter mediate- hyperon–nucleon interaction Superconducting Cyclotron of v iolat ion in t he CK M mat ri x is mass (10 2–105 solar masses) blac k and neutron–star interiors, the Variable Energy Cyclotron estimated to be of the order of just hole – prev iously a missing lin k where st range mat ter may be Cent re in Kol kata – t he only 10–32 e cm, the PSI result places an in t he evolut ion of stellar to present: this is the energy that superconducting cyclotron in even more stringent upper limit supermassive black holes (ApJL is released when a hypertriton India, and one of only a handful on t he as-yet ine x plicably small 892 L25). forms. The collaboration also of superconducting cyclotrons amount of CP v iolat ion in QCD: found no evidence for a mass operating worldwide. A similar the so-called strong CP problem. First physics for Belle II difference between hypertriton mac hine to t hose at M ic hig an A lit t le over a year since Belle II and antihypertriton: a test of State University and Texas Not from a lab beg an ta k ing data at t he CPT symmetry. A&M University, the cyclotron Researc hers in t he US, t he UK SuperKEKB collider in Japan, the will be used for nuclear physics and Aust ralia have dismissed collaboration has published its Dyons elude MoEDAL and t he t reatment of ocular speculat ion t hat SA RS-CoV-2 first physics analysis, using data In 1969, Julian Sc hw inger melanoma, a type of cancer that might have orig inated from a from t he Belle II pilot r un in 2018: e x tended Dirac’s concept of develops in cells that produce laborator y in Wuhan (Nat. Med. a searc h for inv isibly decay ing Z′ t he mag net ic monopole by melanin. One of t he largest doi: 10.1038/s41591-020-0820-9). bosons, whic h would const it ute speculat ing t hat par t icles might cryogenic installations in Asia, Genet ic data ir ref utably show ev idence for physics beyond t he car r y bot h elect ric and mag net ic the project builds on the legacy t hat SA RS-CoV-2 is not derived Quality Production Standard Model (SM). The team c harges (Science 165 3895), and of noted astrophysicist Meghnad from any prev iously used v ir us scoured four mont hs of data for today “dyons” are of ten a feat ure Sa ha, who master minded t he bac kbone, say t he aut hors, who t he Z′ in t he process e +e– → μ +μ–Z′ of g rand unified t heories. The assembly of India’s first nor mal- compared its genome to SA RS-CoV, and for a lepton-flavour v iolat ing MoEDA L collaborat ion at CERN conducting cyclotron in Calcutta whic h orig inated in a food market Z′ in e +e– → eμZ′, by look ing for has now conducted t he first during t he Second World War. in Guangdong in April 2003.

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Reports from the Large Hadron Collider experiments ATLAS Tau pairs speed search for heavy Higgs bosons

4 10 –1 data March 2020 A/H → ττ ATLAS √s = 13 TeV, 139 fb 60 –1 • Full Beamline Solutions 3 top quarks √s = 13 TeV, 139 fb 10 τhad τhad b-tag multijet arXiv:2002.12223 + Z/γ* → ττ H → τν 40 √s = 13 TeV, 36.1 fb–1 2 A/H (400), tan β = 6 W → τν • Accelerator and Neutron Instrumentation 10 A/H (1000) × 100, tan β = 12 2018 JHEP 09 139 others 30 + A/H (1500) × 100, tan β = 25 H → tb 10 uncertainty √s = 13 TeV, 36.1 fb–1 • Monochromator and Mirror Systems 20 2018 JHEP 11 085 1 Hb → bbb √s = 13 TeV, 27.8 fb–1 arXiv:1907.02749 events/GeV –1 • High Stability Cryo Coolers 10 H → ZZ → 4l/llνν –1 –2 10 √s = 13 TeV, 36.1 fb 10 2018 Eur. Phys. J. C 78 293 gg → A → Zh

• Experimental Stations tan β –3 –1 Sub-20nrad 10 √s = 13 TeV, 36.1 fb 2018 JHEP 03 174 –4 5 ATLAS preliminary Stability Achieved 10 H → WW → lνlν • Insertion Devices 4 hMSSM, 95% CL limits √s = 13 TeV, 36.1 fb–1 1.5 3 observed 2018 Eur. Phys. J. C 78 24 Two Horizontal-Bounce Cryo-Cooled DCMs expected H → hh → 4b, • Professional Engineering Support bb → γγ/ττ, for Diamond Light Source DLS 1.0 √s = 13 TeV, 27.5–36.1 fb–1 2 2020 Phys. Lett. B 800 135103 obs./exp. 0.5 h couplings [κv, κu, κd] √s = 13 TeV, 36.1–79.8 fb–1 200150 300 400 500 600 1000 2020 Phys. Rev. D 101 012002 tot 1 mT (GeV) 200 300 400 1000 2000 Axilon AG • Emil-Hoffmann Str. 55-59 • 50996 Köln • Germany • +49 (221) 165 324 00 • [email protected] • www.axilon.de Fig. 1. The distribution of the final discriminant in the analysis, mA (GeV) obtained after a fit under the background-only hypothesis, with three signal models overlaid. This particular analysis category Fig. 2. Excluded regions in the hMSSM scenario, overlaying various ATLAS searches for requires two hadronically decaying tau leptons and at least one heav y neutral and charged Higgs bosons. The A /H→ττ search (light grey) excludes a wide b-tagged jet. range of values for high and intermediate values of tan β.

After the discovery of the long‑sought values of tan β – the ratio of the vacuum applying them to events in control regions Prevent epidemic Higgs boson at a mass of 125 GeV, a major expectation values of the two Higgs dou‑ representative of the event selection. The tot question in particle physics is whether blets, and one of the key parameters of the fi n a l d i s c r i m i n a nt i s o n t h e q u a nt it ym T , outbreaks with the electroweak symmetry breaking model. The heavy neutral Higgs bosons which is built from the combination of the sector is indeed as simple as the one A (CP odd) and H (CP even) are produced transverse masses of the two tau‑lepton implemented in the Standard Model mainly via gluon–gluon interactions or decay products (fig ure 1). mathematical modeling (SM), or whether there are additional in association with bottom quarks. Their The data agree with the prediction Higgs bosons. Additional Higgs bosons branching fractions to tau leptons can assuming no additional Higgs bosons, and simulation. would occur, for example, in the pres‑ reach sizeable values across a large part despite a small, non‑significant excess ence of a second Higgs field, as realised of the model‑parameter space, making around a putative signal mass value of in two‑Higgs doublet models, among this channel particularly sensitive to a 400 GeV. The measurement places lim‑ Using math to analyze the spread of epidemic diseases which is the well‑known minimal super‑ wide range of MSSM scenarios. its on the production cross section that is not a new concept. One of the first compartmental symmetric extension of the SM (MSSM). The new ATLAS search requires the can be translated into constraints on models of mathematical epidemiology dates back The discovery of additional Higgs bos‑ presence of two oppositely charged MSSM parameters. One realisation of the to 1760 and was presented by Daniel Bernoulli for ons could therefore be a gateway to new tau‑lepton candidates, one of which is MSSM is the hMSSM scenario, in which studying the mortality rate of smallpox. Today, medical symmetries in nature. identified as a hadronic tau decay, and the knowledge of the observed Higgs‑ researchers and public health officials continue to use ATLAS has recently released results of the other as either a hadronic or a leptonic boson mass is used to reduce the number a search for heavy Higgs bosons decaying d e c a y. To pr o fit f r o m t h e e n h a n c e m e nt of of parameters. The A/H → ττ exclusion mathematical modeling and simulation to prevent and into a pair of tau leptons using the com‑ the production of signal events in asso‑ limit dominates over large parts of the control epidemic outbreaks in the modern world. plete LHC Run 2 dataset (139 fb–1 of 13 TeV ciation with bottom quarks at large tan β p a r a m e t e r s p a c e (fi g u r e 2), b ut s t i l l l e a v es proton–proton data). The new analysis values (for example when the heavy Higgs room for possible discoveries at masses The COMSOL Multiphysics® software is used for provides a considerable increase in sen‑ boson is radiated by a b‑quark produced The new above the top‑anti‑top quark production simulating designs, devices, and processes in all fields sitivity to MSSM scenarios compared to in the collision of two gluons), the data are ATLAS search threshold. ATLAS continues to refine this of engineering, manufacturing, and scientific research. previous results. further categorised based on the presence requires the and conduct further searches for heavy The MSSM features five Higgs bosons, or absence of additional b‑jets. One of the Higgs bosons in v arious final states. See how you can apply it to analyzing the spread of presence of epidemic diseases. among which, the observed Higgs boson challenges of the analysis is the misiden‑ Visualization of the can be the lightest one. The couplings of tification of backgrounds with hadronic two oppositely Further reading charged motion of bacteria comsol.blog/epidemiology-simulation the heavy Higgs bosons to down‑type jets as tau candidates. These backgrounds ATLAS Collab. 2020 arXiv:2002.12223. particles in a room leptons and quarks, such as the tau lepton are estimated from data by measuring tau‑lepton ATLAS Collab. 2020 ATL‑PHYS‑PUB‑ with a displacement and bottom quark, are enhanced for large the misidentification probabilities and candidates 2020‑006. ventilation system.

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CMS Control systems for big Science, today First sight of the running of the top-quark mass

In the last decade, control system The coupling between quarks and gluons CMS 35.9 fb–1 (13 TeV) CMS 35.9 fb–1 (13TeV) development has become an established depends strongly on the energy scale of the engineering discipline and less of a scientifi c process. The same is true for the masses 1.05 ABMP16_5_nlo PDF set data unfolded to parton level μ = 476 GeV endeavour that was at times characterised by o f t h e q u a r k s. T h i s e ffe c t – t h e s o ‑ c a l l ed 300 ref NLO predictions in MS scheme ) μ0 = μref the “not-invented-here” viewpoint. (pb) 1.00 ref − “running” of the strong coupling constant tt μr = μf = mt ( μ a n d t h e q u a r k m a s s e s – i s d e s c r i b e d b y t h e t Δ m 200 ABMP16_5_nlo PDF set 0.95 At the turn of the century, very little ready- tt renormalisation group equations (RGEs) mt(mt) = 162 GeV ( μ )/m made and off-the-shelf equipment was t − of quantum chromodynamics (QCD). The /dm NLO extraction from differential σtt −− m (m ) = 164 GeV m available for control systems. The handful tt t t 0.90 100 reference scale μref experimental verification of the RGEs is mt(mt) = 166 GeV of physics labs that had demanding d σ one-loop RGE, n = 5, α (m ) = 0.1191 both an important test of the validity of 0.85 f s z requirements were not commercially QCD and an indirect search for unknown interesting to equipment vendors and the physics, as physics beyond the Standard 400 800 1200 1600 2000 400 600 800 1000 control system engineers were still mostly m − (GeV) μ (GeV) Model could modify the RGEs at scales tt the scientists themselves. Today, a larger probed by the Large Hadron Collider. Fig. 1. Left: the cross section for top-quark pair production as a function of the invariant mass of the system. number of experimental projects and The running of the strong coupling The data are unfolded to the parton level and compared to next-to-leading-order theoretical predictions at advancements in computing have allowed the constant has been established at many different values of the top-quark mass. Right: the observed running of the top-quark mass compared to the widespread standardisation of control system experiments in the past, and, over the past solution of the RGEs at one-loop precision. μ = 476 GeV (purple circle) is the mean of the second mass bin. components and the adoption of good ref 20 years, evidence for the running of the practises and solutions from industry. Photo by Yulia Buchatskaya on Unsplash (DESY, Hamburg) masses of the charm and bottom quarks cases, top quarks decay into a W boson in good agreement with the one‑loop was demonstrated using data from LEP, and a bottom quark. In this analysis, can‑ solution of the RGE, within 1.1 standard During this time, control system packages SLC and HERA, though the running of didate events are selected in the final d e v i a t i o n s, a n d a h y p o t h e t i c a l n o ‑r u n‑ and frameworks have also matured through or harm to its users, primarily when it works to keep overall system responsibility in- community collaboration. The growing control at high energies. A completely fl exible MPS house while outsourcing the control system the top‑quark mass has hitherto proven state where one W boson decays into an ning scenario is excluded at above 95% system integration market in science has implementation does not yet exist for big implementation. elusive. electron and a neutrino, and the other confidence level. also attracted industry players in much larger science but, based on requirements from The CMS collaboration has now, for the decays into a muon and a neutrino. The This novel result supports the validity numbers. This has reduced control system many projects, its ideal features are known. Standardisation is the key trend that has fi r s t t i m e, pr o b e d t h e r u n n i n g o f t h emas cross section was determined using a of the RGEs up to a scale of the order of budgets from being 10% of the machine’s One feature is the reconfi guration of the emerged in the last 10 years with ever more of the top quark. The measurement was maximum‑likelihood fit to multi‑ 1 TeV. Its prec ision is l im ited by system‑ budget to even less than 5%. Today’s MPS depending on the working mode of the complex new scientifi c projects. Today, performed using proton–proton collision differential distributions of final‑state atic uncertainties related to experimen‑ challenge is, therefore, no longer how to machine. Clients also desire integration with integration replaces development as the most data at a centre‑of‑mass energy of 13 TeV, observables, allowing the precision of tal calibrations and the modelling of the implement a control system with state-of-the- the timing and control systems, allowing prominent aspect of a control system project. recorded by the CMS detector in 2016. the measurement to be significantly top‑quark production in the simulation. art technology, but how to do it cheaper and for quick reconfi guration and post-mortem So even though control system components The top quark’s mass was determined as improved by comparison to standard Further progress will not only require a quicker, without sacrifi cing quality. analysis. New MPS designs allow responses are steadily becoming more standardised, a function of the invariant mass of the methods (figure 1). The measured cross sig nificant effor t in improv ing t he cali‑ in the range of microseconds where the speed they are also getting more complex and t o p q u a r k–a nt i q u a r k s y s t e m (t h e e n e r g y section was then used to extract the br a t i o n s o f t h e fi n a l‑s t a t e o bj e c t s, b ut a l s o In this article, I will outline some of the of light becomes one of the constraints. require more time and effort for integration. scale of the process), by comparing dif‑ value of the top‑quark mass as a func‑ substantial theoretical developments. main points that you must consider when The main issues today are how will all the ferential measurements of the system’s tion of the energy scale. The running was implementing a control system for a New demanding physics machines require components fi t into the main architecture, production cross section with theoretical determined with respect to an arbitrary Further reading modern machine. complex timing systems. Features such as what will the interfaces be, and how shall predictions. In the vast majority of the reference scale. The measured points are CMS Collab. 2020 Phys. Lett. B 803 135263. virtual accelerators, timing super-cycles and the engineers address the requirements. Basic or multiple control system packages event acknowledgements are becoming more Project managers, therefore, must make early ALICE Traditionally, the fi rst decision that the common. It is now almost agreed that existing choices regarding the main architecture and project manager and control system engineer – bespoke – timing solutions cannot provide components and consider all control system ALICE extends quenching studies to softer jets makes is which control system package to all the necessary functionality. But these development aspects if they want to avoid use. Luckily, today’s most popular control solutions can be employed as the underlying costly problems down the road. system packages are quite mature and with transmission layer, to which customisation Je t s a r e t h e m o s t a b u n d a nt h i g h‑ e n e r g y ALICE is lisions, where, unlike in proton‑proton allow the measurements to cover the a wide enough scope that you will be able to can be added. Put simply: one can purchase In short, control system development is, with objects produced in collisions at the LHC, actively collisions, they may interact with the lowest jet transverse momentum (pT,jet) fi nish your project whatever your choice. the transport layer, whereas the machine- time, becoming increasingly an engineering and often contaminate searches for new working constituents of the quark‑gluon plasma. region measured at the LHC, where jet specifi c application layer must be individually discipline and less of a scientifi c one. p h y s i c s. I n h e a v y‑i o n c ol l i s i o n s, h o w e v e r, to further Since jet production and interactions modification effects are predicted to be these collimated showers of hadrons are can be computed in perturbative QCD, strongest. The measured jet yields in Nevertheless, some scientifi c facilities, adapted for each project. constrain such as big physics machines, use more not a background but one of the main comparing theoretical calculations to P b ‑P b c ol l i s i o n s e x h i bit s t r o n g s u p pr e s‑ ABOUT THE AUTHOR theoretical than one control system. In our experience, Focus on development and standardisation Rok Šabjan is currently the Technical tools to probe the deconfined state of measurements can provide insight to sion compared to pp collisions, consistent Advisor and Sales Director for the strongly interacting matter known as predictions the properties of the quark‑gluon plasma. with theoretical expectations that jets it is better to avoid mixing and matching Building any complex system from Scientifi c domain at Cosylab and is also several control system packages, if at all many components is always a daunting one of the co-founders of the company. t he quark‑gluon plasma. in both pp In this spirit, the ALICE collaboration lose energy as they propagate through the possible. In general, we believe that you engineering task but control system Rok has a bachelor’s in physics and an There are many open questions about and Pb-Pb has measured the inclusive jet production q u a r k‑g lu o n pl a s m a (fi g u r e 1). For r e la‑ executive MBA, with fi elds of expertise should clearly defi ne the functionalities and development has an even more complicated including EPICS, control system the structure of the quark‑gluon plasma: collisions yield in both Pb‑Pb and proton–proton tively narrow R = 0.2 jets, the data show requirements for the interfaces. And don’t cycle: defi ne specifi cations, architecture, architecture and integration, project What are the relevant degrees of freedom? (pp) collisions at a centre‑of‑mass energy stronger suppression at lower pT, jet than management and consulting. Ho w d o h i g h‑ e n e r g y q u a r k s a n d g lu o n s o f 5.02 TeV. Je t s w e r e r e c o n s t r u c t e d f r o m at higher p , suggesting that lower p forget about documentation and maintenance design, prototyping, test procedures; then In his free time, Rok likes to spend T,jet T,jet of the systems. It is usually best to adopt implement, write documentation, test, time with his family, read, hike and play interact with the hot QCD medium? Do a combination of information from the jets lose a larger fraction of their energy. established best practises and learn from the debug and gain site acceptance. Project inline hockey. factorisation and universality hold in ALICE tracking detectors and electro‑ A d d it io n a l l y, t h e d a t a s h o w n o s i g n i fic a nt experience of previous similar projects. managers are increasingly aware of the this extreme environment? To answer magnetic calorimeter for a variety of jet R dependence of the suppression within development process itself, so more things these questions, experiments study radii R. The detectors’ excellent perfor‑ the uncertainties of the measurement, s Machine protection and timing systems require focus. Control system engineers must how je t s a re mo d i fie d i n heav y‑ion c ol‑ mance with soft tracks was exploited to which places constraints on the angu‑ A reliable, fast and fl exible machine- think of the logistics of installation and error Cosylab, Control System Laboratory protection system (MPS) is a critical safety handling while also planning for testing and Tel +386 1 477 66 76 feature that prevents damage to the machine debugging. It usually makes the most sense Email [email protected] | Web www.cosylab.com CERN COURIER MAY/JUNE 2020 19

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lar distribution of the “lost” energy. physics themselves. This new set of meas‑ Several theoretical models, span‑ ALICE R = 0.2 urements was performed systematically ...the power in microwaves! ning a range of physics approximations 1.4 from R = 0.1 to R = 0.6, in order to span from Pb–Pb 0–10% √s NN = 5.02 TeV from jet‑medium weak‑coupling to pp √s = 5.02 TeV small R, where hadronisation effects are strong‑coupling, were compared to the 1.2 lead,ch large, to large R, where underlying event |ηjet| < 0.5 pT > 5 GeV data. The models are able to generally effects are large. These data can be used describe the trends of the data, but sev‑ to constrain the perturbative structure 1.0 eral models exhibit hints of disagree‑ LBT of the inclusive jet cross section, as well ment with the measurements. These data SCETG as hadronisation and underlying event ULTRA AVAILABLE complement existing jet measurements 0.8 hybrid model, Lres = 0 e ffe c t s, w h i c h a r e o f br o a d i nt e r e s t t ohe AA

from ATLAS and CMS, and take advantage R hybrid model, Lres = 2/(πT) high‑energy physics community. JEWEL, recoils on, 4MomSub of ALICE’s high‑precision tracking sys‑ 0.6 Going forward, ALICE is actively work‑ JEWEL, recoils off AMPLIFIERS tem to provide additional constraints on ing to further constrain theoretical pre‑ jet‑quenching models in heavy‑ion colli‑ dictions in both pp and Pb‑Pb collisions 0.4 sions at low pT. Moreover, these measure‑ by exploring complementary jet meas‑ ments can be used in combination with urements, including jet substructure, FOR ACCELERATOR & ALICE 0–10% other jet observables to extract properties 0.2 heavy‑flavour jets, and more. With a correlated uncertainty of the medium such as the transverse nearly 10 times larger Pb‑Pb data sample shape uncertainty m o m e nt u m d i ff u s i o n p a r a m e t e r, w h i c h 0 collected in 2018, upcoming analyses of MEDICAL APPLICATIONS describes the angular broadening of jets the data will be important for connecting 0 50 100 as they traverse the quark–gluon plasma, observed jet modifications to properties pT,jet (GeV) as a function of the medium temperature of the quark‑gluon plasma. TMD in collaboration with Rosatom - NIITFA is now and the jet pT. Fig. 1. The ratio of jet yields in Pb-Pb collisions relative to The “reference” measurements in pp collisions (appropriately scaled) compared to four Further reading able to offer revolutionary, ultra-available RF solid state pp collisions contain important QCD theoretical predictions. ALICE Collab. 2020 Phys. Rev. C 101 034911. amplifiers for scientific and medical applications. LHCb LHCb New SMOG on the horizon Innovative power combining and control system results in: LHCb will soon become the first LHC an alignment precision of 200 μm. Like • Ultra-compact systems, typically one Applications: experiment able to run simultaneously the VELO halves, they can be opened for 19” rack / 100 kW (pulse) with two separate interaction regions. safety during LHC beam injection and • Synchrotrons, LINACs for scientific, As part of the ongoing major upgrade tuning, and closed for data‑taking. The • CW / Pulse Systems, long pulse experimentation/particle physics of the LHCb detector, the new SMOG2 cell is sufficiently narrow that as small • Modular Solid State architecture, and Spallation systems –15 fixed‑target system will be installed in a flow as 10 particles per second will compact modules (<10 kg) • Medical therapy equipment long shutdown 2. SMOG2 will replace the yield tens of pb–1 of data per year. The new previous System for Measuring the Over‑ injection system will be able to switch Fig. 1. Half of the the LHC, by improving our knowledge Courtesy Honeywell Aerospace • Highly Maintainable with Hot Swap • Cyclotrons for radioisotope lap with Gas (SMOG), which injected noble between gases within a few minutes, and SMOG2 storage cell of the parton distribution functions of capability production gases into the vacuum vessel of LHCb’s in principle is capable of injecting not just (black), attached to both protons and nuclei, particularly at • Wall Plug efficiency competitive with • Option to upgrade existing systems vertex detector (VELO) at a low rate with noble gases, from helium up to krypton its wake-field high‑x, where new particles are most often tube technology (55% demonstrated) the initial goal of calibrating luminosity and xenon, but also several other species, suppressor (black, expected, and will inform the physics pro‑

measurements. The new system has sev‑ including H2, D2, N2, and O2. right) and the VELO grammes of proposed next‑generation • Highly robust to VSWR mismatch Other Products: eral advantages, including the ability to SMOG2 will open a new window on QCD RF foil (grey, left). accelerators such as the Future Circular • High MTBF and Low MTTR • High Power, Very Low Phase Noise reach effective area densities (and thus studies and astroparticle physics at the Collider. The gas target will also allow TWT Amplifiers luminosities) up to two orders of magni‑ LHC, performing precision measurements the dynamics and spin distributions of • No loss of power from any single tude higher for the same injected gas flux. in poorly known kinematic regions. Col‑ quarks and gluons inside unpolarised element failure • Brazed UHV components S MO G2 i s a g a s t a r g e t c o n fi n e d w it h i n lisions with the gas target will occur at a nucleons to be studied for the first time • High efficiency enhances reliability • Electron Guns a 20 cm‑long aluminium storage cell that nucleon–nucleon centre‑of‑mass energy at the LHC, a decade before corresponding is mounted at the upstream edge of the of 115 GeV for a proton beam of 7 TeV, measurements at much higher accuracy • Frequencies available from • Diffusion Bonding VELO, 30 cm from the main interaction and 72 GeV for a Pb beam of 2.76 TeV per are performed at the Electron‑Ion Collider 2 MHz to 1.3 GHz • Vacuum/Hydrogen Brazing p oi nt, a n d c o a x i a l w it h t h e L HC b e a m (fi g‑ nucleon. Due to the boost of the interact‑ in the US. Studying particles produced in • MW power capability ure 1). The storage‑cell technology allows ing system in the laboratory frame and the collisions with light nuclei, such as He, • Speciality Cleaning a very limited amount of gas to be injected forward geometrical acceptance of LHCb, and possibly N and O, will also allow LHCb in a well defined volume w it hin t he LHC it will be possible to access the largely to give important inputs to cosmic‑ray beam pipe, keeping the gas pressure and unexplored high‑x and intermediate Q2 physics and dark‑matter searches. Last For more information on our leading edge d e n s it y pr o fi l e u n d e r pr e c i s e c o nt r ol, and regions. but not least, SMOG2 will allow LHCb to ensuring that the beam‑pipe vacuum level Combined with LHCb’s excellent parti‑ perform studies of heavy‑ion collisions at technology email us at [email protected] stays at least two orders of magnitude cle identification capabilities and momen‑ large rapidities, in an unexplored energy below the upper threshold set by the LHC. tum resolution, the new gas target system r a n g e b e t w e e n t h e SP S a n d R H IC, o ffe r i n g or visit www.tmd.co.uk With beam‑gas interactions occurring at will allow us to advance our understanding new insights into the QCD phase diagram. roughly 4% of the proton–proton collision of the gluon, antiquark, and heavy‑quark rate at LHCb, the lifetime of the beam will components of nucleons and nuclei at Further reading b e e s s e nt i a l l y u n a ffe c t e d. T h e c e l l i s m ade large‑x. This will benefit searches for LHCb Collab. 2018 LHCb‑PUB‑2018‑015. of two halves, attached to the VELO with physics beyond the Standard Model at LHCb Collab. 2019 LHCB‑TDR‑020.

20 CERN COURIER MAY/JUNE 2020 Courtesy CERN

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Meet us at IPAC2020: 10th - 15th of May 2020 in Caen, FRA FIELD HIGH VOLTAGE NOTES POWER SUPPLIES MAGNET Reports from events, conferences and meetings POWER SUPPLIES FCC PhysiCs and ExPErimEnts WorkshoP HIGH CURRENT Circular colliders eye Higgs self-coupling POWER SUPPLIES Physics beyond the Standard Model must exist, to account for dark matter, HIGH PRECISION the smallness of neutrino masses and POWER SUPPLIES the dominance of matter over antimat- ter in the universe; but we have no real clue of its energy scale. It is also widely BASIC RESEARCH recognised that new and more precise AT THE HIGHEST LEVEL tools will be needed to be certain that the 125 GeV boson discovered in 2012 Heinzinger has played a role in research for a very long time is indeed the particle postulated by thanks to its expertise and passion. In addition to the European Brout, Englert, Higgs and others to have CERN facility in Geneva, companies, universities, colleges and m o d i fie d t h e b a s e p o t e nt i a l o f t h e whole state institutions are investing in research. Whether it be testing universe, thanks to its coupling to itself, and measuring equipment, accelerator technology or HV pow- liberating energy for the masses of the W and Z bosons.

er supplies for particle detectors: High-specification technical Rosenheim (Germany) 4 I 83026 GmbH I Anton-Jakob-Str. Heinzinger electronic I www.heinzinger.com 2458 0 I email: info @heinzinger.de +49 8031 P: equipment from Heinzinger helps to produce reliable and resilient To tackle these big questions, and results in laboratories and testing centers all over the world. others, the Future Circular Collider (FCC) study, launched in 2014, pro- posed the construction of a new 100 km c i r c u l a r t u n n e l t o fi r s t h o s t a n i nt e n s it y- frontier 90 to 365 GeV e+e– collider (FCC-ee), and then an energy-frontier (> 100 TeV) hadron collider, which could potentially also allow electron–hadron collisions. Potentially following the High-Luminosity LHC in the late 2030s, FCC-ee would provide 5 × 1012 Z decays – o v e r fi v e or d e r s o f m a g n it u d e m or e t h an the full LEP era, followed by 108 W pairs, 106 Higgs bosons (ZH events) and 106 top- quark pairs. In addition to providing the highest parton centre-of-mass energies foreseeable today (up to 40 TeV), FCC-hh would also produce more than 1013 top quarks and W bosons, and 50 billion Higgs bosons per experiment.

Rising to the challenge Following the publication of the four- volume conceptual design report and submissions to the European strategy discussions, the third FCC Physics and Rhyming couplings Delegates at the FCC workshop in January explored effective field theories for high-mass Experiments Workshop was held at CERN new physics that decouples as 1/M 2. This working diagram shows correlations (connections) and achievable from 13 to 17 January, gathering more precisions (outer ring) for modified Higgs and electroweak couplings at candidate next-generation +e e– colliders than 250 participants for 115 presenta- (arXiv:1907.04311). Many correlations vanish when hadron-collider results are added. (Credit: J de Blas et al.) tions, and establishing a considerable programme of work for the coming years. include all the heavy Standard Model in the experiments – a very promising Special emphasis was placed on the fea- particles (W±, Z, H, t). condition for vertexing, lifetime meas- sibility of theory calculations matching In parallel, a significant focus of the urements and the separation of bottom the experimental precision of FCC-ee. meeting was on detector designs for and charm quarks from light-quark and The theory community is rising to the FCC-ee, with the aim of forming experi- gluon jets. Elegant solutions have been challenge. To reach the required precision mental proto-collaborations by 2025. The found to bring the final-focus magnets at the Z-pole, three-loop calculations of design of the interaction region allows close to the interaction point, using s quantum electroweak corrections must for a beam vacuum tube of 1 cm radius either standard quadrupoles or a novel

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FIELD NOTES FIELD NOTES

magnet design using a superposition of possible subsequent hadron collider must keystone of the FCC physics programme. QM2019 off-axis (“canted”) solenoids. Delegates be determined. A bolder idea discussed As said above, this self-interaction is discussed solutions for vertexing, track- at the workshop aims to improve both the key to the electroweak phase tran- ing and calorimetry during a Z-pole run luminosity (by a factor of 10) and energy sition, and could have important cos- at FCC-ee, where data acquisition and reach (perhaps up to 600 GeV), by turning mological implications. Building on the trigger electronics would be confronted FCC-ee into a 100 km energy-recovery solid foundation of precise and model- with visible Z decays at 70 kHz, all of linac. The cost, and how well this would independent measurements of Higgs cou- which would have to be recorded in full actually work, are yet to be established. plings at FCC-ee, FCC-hh would be able to detail. A new subject was π/ K / p i d e nt i fi- Finally, a tantalising possibility is to access Hμμ, Hγγ, HZγ and Htt couplings cation at energies from 100 MeV to 40 GeV produce the Higgs boson directly in the at sub-percent precision. Further study – a consequence of the strategy process, s-channel: e+e– → H, sitting exactly at a of double Higgs production at FCC-hh during which considerable interest was centre-of-mass energy equal to that of shows that a measurement of the Higgs expressed in the flavour-physics pro- the Higgs boson. This would allow unique self-coupling could be done with a statis- gramme at FCC-ee. access to the tiny coupling of the Higgs tical precision of a couple of percent with The January meeting showed that boson to the electron. As the Higgs width the full statistics – which is to say that physicists cannot refrain from inves- (4.2 MeV in the Standard Model) is more after the first few years of running the energy. LHC and RHIC measurements Fundamental to zero momentum in Pb–Pb collisions form of jet or large-momentum hadron tigating improvements, in spite of the than 20 times smaller than the natural precision will already have been reduced are complementary as they cover a broad understanding at the LHC, and by new measurements of modifications) remains absent in the impressive statistics offered by the energy spread of the beam, this would to below 10%. This is much faster than r a n g e o f Q GP t e m p e r a t u r e s a n d d i ffe r i n More than 800 t h e e l l i p t i c flo w o f D m e s o n s a n d m uons measurements carried out to date. baseline design of FCC-ee. Increasing Physicists require a beam manipulation called previously realised, and definitely con- the balance of quark- and gluon-initiated participants from charm and beauty decays, as well The field is now looking forward to - the number of interaction points from cannot mono chromatisation and a careful run stituted the highlight of the workshop. jets, with the former dominating at RHIC discussed the latest as bound states of heavy quarks (char- future programmes at the LHC and RHIC, two to four is a promising way to nearly ning procedure, which a task force was and the latter dominating at the LHC. results of the monia and bottomonia). These meas- which were extensively reviewed at the double the total delivery of luminosity for refrain from nominated to study. Alain Blondel LPNHE Paris, CERN Measurements in the sectors of heavy heavy-ion urements suggest a stronger degree of conference. At the LHC, the heavy-ion little extra power consumption, but con- investigating The ability to precisely probe the and the University of Geneva, and quarks and rarely-produced light nuclei programmes at the collective behaviour for light than heavy injectors and the experiments are cur- struction costs and compatibility with a improvements self-coupling of the Higgs boson is the Panagiotis Charitos CERN. (such as deuterons, 3He and hypertriton, a LHC and RHIC. quarks, and further constrain estimates rently being upgraded. In particular, the pnΛ b o u n d s t a t e) a l s o s t r o n g l y b e n e fit e d of the QGP viscosity. Such estimates also heavy-ion-dedicated ALICE detector Quark M atter 2019 from the large recent samples recorded require an understanding of heavy-quark is undergoing major improvements, at the LHC. In particular, their degree hadronisation, which was discussed in with readout and tracker upgrades of collective behaviour could be stud- the light of new results at RHIC and the that will provide larger samples and LHC and RHIC heavy ions dovetail in Wuhan ied in much greater detail. The family LHC, which indicate an increased pro- better performance for heav y-flavour of QGP probes in the heavy-quark sec- duction of charmed baryons with respect selection. Run 3 of the LHC, which is QM2019 tor has been extended with new mem- to mesons, at low momentum in both scheduled to start in 2021, will provide bers at the LHC by first observations of pp and nucleus–nucleus collisions, when integrated luminosity increases rang- the X(3872) exotic hadron and of top– compared to expectations from electron– ing from one order of magnitude for antitop quark production. In the sector of positron collisions. the data samples based on rare trig- electromagnetic processes, new experi- gers to two orders of magnitude for mental observations were presented for Dynamical origins the minimum-bias (non-triggered) t he fi r s t t i me at t he c on fe re nc e, i nc lud- While there is strong evidence for the samples. At RHIC, the second beam- ing the photo-production of dileptons production of QGP in nuclear collisions, energy-scan programme is now provid- in collisions with and without hadronic the situation is much less clear in the ing the STAR experiment with higher overlap, and light-by-light scattering. collisions of small systems. The momen- precision data to search for the energy These effects are induced by the inter- tum correlations and azimuthal modula- evolution of QGP effects, and the new action of the strong electromagnetic tions that characterise the large nuclear sPHENIX experiment aims at improved fie l d s o f t h e t w o P b nu clei(Z = 82) passing collisions were also observed in smaller measurements of jets and heavy quarks close to each other (CERN Courier January/ collision systems, such as p–Pb at the from 2023. Low-energy programmes at February 2020, p17). LHC, p–Au, d–Au and 3He–Au at RHIC, the CERN SPS, NICA, FAIR, HIAF and and even pp. The persistence of these J-PARC, which target a systematic New information correlations in smaller collision systems, exploration of heavy-ion collisions with In nuclear collisions, the fluid-dynam- down to pp collisions where it is unlikely high baryon density to search for the ical flow of the QGP leaves an imprint that an equilibrated system could be cre- onset of deconfinement and the pre- in the azimuthal distribution of soft ated, may offer an inroad to understand dicted QCD critical point, were also dis- The 28th International Conference early universe, matter is a quark–gluon Colourful physics rare probes of the QGP, such as jets and particles as the initial geometry of the how the collective behaviour of the QGP cussed in Wuhan, and the updated plans on Ultrarelativistic Nucleus–Nucleus plasma (QGP), in which quarks and gluons The latest edition of heavy quarks, with unprecedented pre- collision is translated to flow through arises from the microscopic interaction for the US-based Electron-Ion Collider Collisions, also known as “Quark are not confined w it h in hadrons. In t he the International cision. New constraints on the energy pressure gradients. Its experimental of its individual constituents. New meas- (EIC), which is foreseen to be constructed Matter”, took place in Wuhan, China, recent editions of Quark Matter, much Conference on loss of partons when traversing the trace is multi-particle angular correla- urements on multi-particle correlations a t Br o o k h a v e n Na t i o n a l L a b or a t or y, w e r e in November. More than 800 partici- attention has also been devoted to the Ultrarelativistic high-density medium were presented, tions between low-momentum parti- were presented and the dynamical origin presented. With ep and e-nucleus inter- pants discussed the latest results of the study of emergent QCD phenomena Nucleus–Nucleus pushing the limits of jet measurements cles, even at large rapidity separations. In of the collectivity in small systems was actions, the EIC will provide unprece- heavy-ion programmes at the Large in high-multiplicity proton–proton Collisions, Quark to lower transverse momenta and larger non-central nucleus–nucleus collisions discussed. Small expanding QGP drop- dented insights into the structure of the Hadron Collider and at Brookhaven’s and proton–nucleus collisions, which Matter 2019, radii: jet modifications are now meas- that have an elliptical initial geometry, The LHC lets, colour connections of overlapping proton and the modification of parton Relativistic Heavy-Ion Collider (RHIC), resemble the collective effects seen in took place in Wuhan ured in the transverse momentum range the resulting azimuthal modulation of and RHIC QCD strings, and final-state rescattering densities in nuclei, which will benefit as well as the most recent theoretical nucleus–nucleus collisions and pose the in November. from 40 to 1000 GeV and in the jet radius particle momentum distribution is called together cover at partonic or hadronic level are among our understanding of the initial con- - elliptic flow. New information on col- the possible mechanisms that are pro- developments. The focus of these stud intriguing question of whether a QGP can (resolution parameter) range 0.2 to 1. The a broad range ditions for nucleus–nucleus collisions. ies is the fundamental understanding of also form in “small-system” collisions. internal structure of jets was studied not lective behaviour and on the dynamics posed to describe these observations. strongly interacting matter at extremes The large data sample from the Pb– only by the LHC experiments, but also of heavy-quark interactions in the QGP of quark- While many of the signs characteristic Andrea Dainese INFN Padova, of temperature and density. In these Pb period of LHC Run 2 in 2018 allowed by the PHENIX and STAR collaborations w a s a d d e d b y a fi r s t m e a s u r e m e nt o f t he gluon-plasma of the QGP are seen in small-system Aleksi Kurkela CERN and Stavanger s conditions, which also characterise the ALICE, ATLAS, CMS and LHCb to study at the 25-times lower RHIC collision D-meson momentum distribution down temperatures collisions, parton energy loss (in the University, and Michael Weber SMI Vienna.

24 CERN COURIER MAY/JUNE 2020 CERN COURIER MAY/JUNE 2020 25

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FIELD NOTES

Vi cosmoloGy and the Quantum Vacuum Cosmologists confer with quantum theorists S Odintsov The sixth Cosmology and the Quantum Emilio Elizalde. Wormholes are usually ARMCO® Pure Iron Vacuum conference attracted about 60 related with exotic matter, however, they ARMCO® Pure Iron theoreticians to the Institute of Space may in alternative gravity be caused by Sciences in Barcelona from 5 to 7 March. m o d i fic a t i o n s t o t h e g r a v it a t i o n a l equa- High Purity Iron for This year the conference marked the tions of motion. Iver Brevik (Trondheim) High Purity Iron for 70th birthday of Spanish theorist Emilio gave an excellent introduction to viscos- Magnetic Applications Elizalde. He is a well known specialist in ity in cosmology. Rather exotic worm- Magnetic Applications mathematical physics, field theory and holes were presented by Sergey Sushkov gravity, with more than 300 publications (Kazan), while black holes in modified and three monographs on the Casimir gravity were discussed by Gamal Nashed effect and zeta reg ularisat ion. (C a i r o). A flu i d a p pr o a c h t o t h e d a r k-en- These meetings bring together ergy epoch and the addition of four forms researchers who study theoretical (antisymmetric tensor fields with four cosmology and various aspects of the indices) to late universe evolution was quantum vacuum such as the Casimir given by Diego Saez (Vallodolid) and Mar- effect. This effect manifests itself as an iam Bouhmadi-Lopez (Bilbao), respec- attractive force that appears between tively. Novel aspects of non-standard plates which are extremely close to each quintessential inflation were presented other. As it is related to the quantum by Jaime Haro (Barcelona).

vacuum, it is expected to be important Many interesting talks were given in cosmology as well, giving a kind of Even more attention was paid to String inspiration by young participants at this meeting. effective induced cosmological constant. theoretical cosmology. The evolution Ekaterina Pozdeeva The exchange of ideas between cosmol- Manuel Asorey (Zaragoza), Mike Bordag of the early and/or late universe in dif- (Skobeltsyn ogists on the one side and quantum- (Leipzig) and Aram Saharian (Erevan) ferent theories of modified gravity was Institute of Nuclear field-theory specialists on the other will www.aksteel.eu discussed various aspects of the Casimir discussed by several delegates, with Physics, Moscow) surely help in the further development e ffe c t for s c a l a r fie l d s a n d g a u g e t h e or ies. Enrique Gaztanaga (Barcelona) express- discusses the of rigorous approaches to the construc- Joseph Buchbinder gave a review of one- ing an interesting point of view on the stability of de Sitter tion of quantum gravity. It also opens loop effective action in supersymmet- inflationary universe, arguing for two solutions in the window onto a much better account ric gauge theories. Conformal quantum early inflat ionar y periods. “Gauss-Bonnet” of quantum effects in the history of RELIABLE POWERED BY gravity and quantum electrodynamics Martiros Khurshudyan and I discussed gravity. the universe. in de Sitter space were presented by modified-gravity cosmology with the Enrique Alvarez (Madrid) and Drazen unification of inflation and dark energy, Sergey Odintsov Institute of Space UNDER ALL Glavan (Brussels), respectively. and wormholes, building on work with Sciences, Barcelona. CONDITIONS. Joint Ger m an–a r menian internship in accelerator physics Yerevan hosts early-career accelerator internship Heading into the unknown to open new horizons The World’s Most Advanced demands reliable tools. Help turn your resarch

CANDLE Institute CANDLE goals into reality. The inaugural joint German–Armenian Working together Digital Pulse Processor internship in accelerator physics was German and for high-rate Spectroscopy Vacuum valve solutions and bellows held at the CANDLE Institute in Yerevan, Armenian from VAT provide unfailing reliability Armenia, from 29 September to 5 October undergraduates and enhanced process safety – 2019. I n t h i s fi r s t r o u n d, 1 2 u n d e r g r a d u a t es teamed up to tackle at the University of Hamburg joined 11 accelerator-physics • Up to 8 channels under all conditions. students from Yerevan State University to experiments in of simultaneous form eight small teams. Each team worked Yerevan. processing its way through an experiment under the supervision of experts from both nations, • Over 3 Mcps interacting with physicists in a laboratory processed by setting for the first time in many cases. The goal of the programme of week-long each channel internships, which was supported by the [email protected] G e r m a n Fe d e r a l For e i g n O ffic e, i s t o i nte- Tel: +1-510-401-5760 grate accelerator physics and technology accelerator technology in Armenia. next steps are S-band linac acceleration www.xia.com into undergraduate courses, and provide CANDLE is a proposed third-generation up to 20–50 MeV and the generation of students with an early experience of inter- synchrotron-radiation facility in Arme- coherent and tunable THz-radiation in national collaboration. It will make use nia. As a first step towards its realisation, an undulator. of eight experimental stations recently AREAL, an ultrafast laser-driven electron set up to foster young academics learning accelerator, has been constructed. The Joerg Rossbach University of Hamburg.

26 CERN COURIER MAY/JUNE 2020 www.vatvalve.com

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ADVERTISING FEATURE FEATURE SYNCHROTRON SCIENCE

Cables, heaters and temperature measurement SYNCHROTRONS ON THE for synchrotron and light source CORONAVIRUS FRONTLINE We are proud of our heritage and electrical noise. The cables are good Temperature measurement history, and have been a trusted for various adverse conditions and Temperature sensors can be supplier to customers throughout the environments, including bake out, manufactured to customers’ world for more than 60 years. nuclear, UHV and Rogowski coils. specific designs, or to our standard Accelerator physicist Tessa Charles designs with a variation of cold end When it comes to market-leading Electric heaters terminations and hot junctions, also describes the impressive progress semi-rigid metal sheath cables, Our AerOrod electric heaters are including multipoint assemblies, being made by synchrotron temperature measurement and offered in a wide range of sizes, styles Okazaki can also provide Hoskins electric heaters, we lead the way. and terminations. Among the list of 2300® in Type K and Type N, which X-ray facilities to solve the benefits are: are very accurate at a higher structure of the SARS-CoV-2 In choosing us as your temperature temperature compared to the partner, you will have access to an • Flexibility standard cable. virus – a first step towards unrivalled range of the most highly • Corrosion resistance t he de velopment of ne w d r ugs accurate and advanced temperature- • High-watt density related products, designed to • Long life in service and vaccines. operate in some of the harshest • Fast time response environments. t a time when many countries are locking down borders, limiting public gatherings and encouraging Our product range includes: A isolation, the Diamond Light Source in Oxfordshire, We also manufacture cryogenic UK, has been ramping up its activities, albeit in an organ- • Metal sheathed mineral assemblies for temperatures down ised and controlled manner. The reason: these scientists insulated cables, including to 1.5K. are working tirelessly on drug-discovery efforts to quell thermocouple cable. COVID-19. • Electric heaters The assemblies that we manufacture It i s a s t or y t h at r e q u i r e s f a s t d e t e c t or s, r e l i a ble r o b o t ic s • Temperature measurement are suitable for 1.5K to 2300 °C and a n d p o w e r f u l c o m p ut i n g i n f r a s t r uc t u r e s, a r t i fic i a l i nt e l li- assemblies from 1.5K to 2300 °C diameters of 0.08 mm to 26 mm. gence, and one of the brightest X-ray sources in the world. And it is made possible by international collaboration, dedication, determination and perseverance. Unlocking the puzzle Representation of the 3D structure of the main Magnetic assemblies Synchrotron light sources are particle accelerators SARS-CoV-2 protease – an enzyme much smaller than the virus, which goes on capable of producing incredibly bright X-rays by forcing to process the viral proteins that have been made, allowing the cell’s life cycle to M a g n et i c s e ns o r s i n a f us i o n ex p e r i m e nt . I n t h e “c o n fi g ur at i o n” c o lum n, m × n m e ans t h e num b e r of t h e s e ns o r s i n t h e p o l o i da l a n d toroidal direction, respectively, and single numbers indicate the numbers of the sensors along poloidal or toroidal paths, except for relativistic electrons to accelerate on curved trajectories. continue. The organisation of alpha helices (coils) and beta sheets (arrows) is often Ro g ow sk i c o i l s fo r H a l o c ur r e nt . Around 50 facilities exist worldwide, enabling studies referred to as the secondary structure of the protein, with the primary and tertiary over a vast range of topics. Fanning out tangentially from structures being the amino-acid sequence and the 3D shape of the protein, Diamond’s 562 m-circumference storage ring are more respectively. (Credit: D Owen/Diamond Light Source.) t h a n 30 b e a m l i n e s e q u i p p e d w it h i n s t r u m e nt at io n t o s e r v e a multitude of user experiments. The intensely bright site would throw a chemical spanner in the works, blocking X-rays (corresponding to a flux of around 9 ×10 12 photons the virus’s ability to replicate and limiting the spread of per second) are necessary for determining the atomic the disease. Coronavirus is the family of viruses respon- structure of proteins, including the proteins that make sible for the common cold, MERS, SARS and others. Novel up viruses. As such, synchrotron light sources around the c or o n a v i r u s, a k a S A R S- C oV-2, i s t h e n e wl y d i s c o v e r e d t y p e world are interrupting their usual operations to work on of coronavirus and COVID-19 is the disease that it causes. mapping the structure of the SARS-CoV-2 virus. Mineral insulated cables (MI) K n o w i n g t h e at o m ic s t r uc t u r e o f t h e v i r u s i s l i k e k n o w i n g Call to arms We manufacture a comprehensive how t he enemy t h i n k s. A 3D v i sua l i s at ion of t he bu i ld i ng On 26 January, Diamond’s life-sciences director, Dave blo c k s o f t h e s t r uc t u r e at a n at o m ic le v e l wo u ld a l lo w s c i- Stuart, received a phone call from structural biologist Zihe range of metal-sheathed MI cables Magnetic measurements conducted using these sensors serve the following entists to understand how the virus functions. Enzymes, R a o o f Sh a n g h a iTe c h Un i v e r s it y i n C h i n a. R a o, a lo n g w it h with an operating range from 1.5K to three purposes: plasma equilibrium reconstruction and control, MHD t h e m ole c u l a r m a c h i n e s t h at a l lo w t h e v i r u s t o r e pl ic at e, a r e his colleague Haitao Yang, had solved the structure of 2300 °C. Both coax and triaxial cables identification, and disruption study. k e y t o t h i s pr o c e s s. S c ie nt i s t s at D i a m o n d a r e e x plor i n g t h e the main SARS-CoV-2 protease with a covalent inhibitor THE AUTHOR can be supplied with hermetically binding site of one enzyme, the main SARS-CoV-2 protease, using the Shanghai Synchrotron Radiation Facility (SSRF) Tessa Charles sealed connectors such as BNC or which is responsible for the breakdown of proteins into in China. Furthermore, they had made the solution freely University of SMA. Cables can be supplied with smaller pieces. A drug that binds to this enzyme’s active and publicly available on the worldwide Protein Data Bank. Melbourne. internal twisted conductors to avoid www.okazaki-mfg.co.uk | [email protected]

CERN COURIER MAY/JUNE 2020 29

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FEATURE SNCRTRN SCIENCE FEATURE SNCRTRN SCIENCE

designed to expedite candidates in drug discovery. Australian Synchrotron, and light sources all over the As of early arch, 15 crystals and fragments have orld have announced rapid-access schemes for research been analysed. Oen attributes the team’s success so far directly related to COVID-19. The community as a whole has to the incredible amounts of data they could collect and a platform called .lightsources.org here scientists Diamond Light Source Light Diamond analyse uicly. ith huge numbers of data sets, they can have a birds-eye vie of calls for proposals and access. could pin don the parameters of the viral protease ith a In addition to alloing the structure of tens of thousands high degree of confi dence. And with the synchrotron light of biological structures to be elucidated such as that of s o u rc e t h e y w e r e a ble t o c r e at e a n d a n a l y s e t h e d i ff r a c t io n the ribosome, which was recognised by the 2009 Nobel patterns rapidly. The same amount of data collected ith Prize in Chemistry – light sources have a strong pedigree in a lab-based X-ray source ould have taen approximately solving the structure of viruses. Development of common 1 years. At Diamond, they ere able to collect the data in anti-viral medication that blocs the actions of the virus a fe days of accumulated beamtime. in the body, such as Tamifl u or Relenza, also relied upon Shedding light An aerial view of the U’s Diamond Light Source (left) and one of its transfer lines in the foreground and storage ring in the synchrotrons to reveal their atomic structure. bacground (right), where ultra-relativistic electrons circulate and produce intense synchrotron radiation. Rapid access M appi ng t he SA R S-CoV-2 protea se st r uc t ures b ound to Synchrotron light sources all over the orld have been small chemical fragments, the Diamond team demonstrated Tists and turns light source. The X-rays are directed and focused don a granting priority and rapid access to researchers to sup- a crystallography- and fragmentation-screen tour de force. A close-up view of beamline onto a crystal and, as they pass through it, they port their eff orts in discovering more about the virus. The resulting and ongoing work is a crucial fi rst step in some residues in diff ract. From the diff raction pattern, researchers can work Researchers at the Advanced hoton Source in Argonne in developing a drug. Forgoing the usual academic route of the active site of bacards to determine the D electron density maps and the US, and at lettra Sincrotrone in Trieste, Italy, are also peer-revie, the Diamond team have made all of their noing the SARS-CoV-2 the structure of the protein. The result is a complex curled trying to identify molecules eff ective against COVID-19, results openly and freely available to help inform public

protease Source Light OenDiamond D ribbon-lie structure ith an intricate mess of tists and in an at tempt to bring us closer to an eff ect ive v accine or heath response and limit the spread of the virus, ith the the atomic (an enzyme), turns of the protein chain. treatment. Researchers at TRA III, a synchrotron light hop e t h at t h i s c a n f a st-t r ac k eff e c t ive t reat ment opt ion s. structure of where the stics T h e D i a m o n d t e a m s e t up nu m e r o u s t r i a l s t r y i n g t o fi n d t h e source at DSY in ermany, are examining several thou- This or is continuing. The researchers at Diamond the irus is represent the optimum conditions for crystallisation of the SARS-CoV-2 sand existing drugs to access whether they are eff ective are testing hundreds of compounds each ee, and ith lie noing protein molecules protease to occur. They modifi ed the pH, the precipitating against the virus. COVID-19 research is also being con- each step they learn something ne about the virus and ho the and the mesh compounds, chemical composition, protein to solution ratio ducted at SSY II at Helmholt-Zentrum erlin, ASTO’s ho to target it.  enemy thins represents the every parameter they could vary, they did. very day they electron density. ould produce a fe thousand trials, of hich only a fe hun- dred ould produce crystals, and even feer ould produce c r y s t a l s o f s u ffi c ie nt q u a l it y. W it h i n a fe w d a y s o f r e c e i v i n g t he gene, t he fi rst c r yst a l s were b ei ng pro duce d. The y were Cryogenic Components paltry and thin crystals but large enough to be tested on one ■ of Diamond’s macro molecular crystallography beamlines. Cryogenic Control & Shut-off Valves atching the results come through, Diamond postdoc ■ Quench Relief Valves David Owen described it as the fi rst moment of intense ■ Single & Multi-Line Johnston Couplings e xcitement. Wit h cr ystals t hat appeared to be “fl at li ke a car ind shield, he as dubious as to hether they ould ■ Check valves and associated products During the phone call, Rao informed Stuart that their d i ff r a c t at a l l. Ne v e r t h e le s s, t h e t e a m pl a c e d t h e c r y s t a l s i n or had been halted by a scheduled shutdon of the the beamline ith a resignation that uicly turned into ■ Focusing on cryogenic temperatures below 100 K SSRF. The Diamond team rapidly mobilised. Since ship- intense curiosity as the results started appearing before ■ Optimized design for low operating cost ping biological samples from Shanghai at the height of the them. At that moment Oen remembers his doubts fad- ■ coronavirus in China as expected to be problematic, the ing, as he thought, this might just or And or it Suitable to operate in high magnetic field and team at Diamond ordered the synthetic gene. A synthetic did. In fact, Owen recalls, “they diff racted beautifully.” ionizing radiation Please visit us at our website: These fi rst diff raction patterns of the SARS-CoV-2 virus gene can be generated provided the ordering of T, A, C and ■ Long maintenance intervals and simple www.weka-ag.ch nucleotides in the DA seuence is non. That synthetic ere recorded ith a resolution of .19 nm high enough gene can be genetically engineered into a bacterium, in this resolution to see the position of all of the chemical groups service requirements case scherichia coli, hich reads the seuence and gener- that allo the protease to do its or. ■ More than 40 years of experience ates the coronavirus protease in large enough uantities y 19 February, through constant adjustments and for the researchers at Diamond to determine its structure learning, the team ne they could gro good-uality and screen for potential inhibitors. crystals uicly. It as time to bring in more colleagues. Liquefaction of gases leven days later on 1 February, the synthetic gene arrived. The XChem team at Diamond joined the mission to set up The same Gas distribution systems At this point, artin alsh, Diamond’s deputy director of life fragment-based screening hereby a vast library of small amount of sciences, and his team (consisting of Claire Strain-Damerell, molecules (fragments) are soaed into crystals of the Gas recirculation systems data collected etra Luaci and David Oen) dropped everything. ith viral protease. These fragments are signifi cantly smaller Hydrogen infrastructure WEKA AG · Schuerlistrasse 8 ith a lab the gene in hand, the group immediately set up experimental and functionally simpler than most drug molecules and are CH-8344 Baeretswil · Switzerland Space infrastructure based ray trials to try to generate protein crystals. In order to deter- a poerful approach to selecting candidates for early drug Phone +41 43 833 43 43 source ould mine the atomic structure, they needed a crystal containing discovery. y 26 February, 6 crystals had been mounted Plasma & fusion research [email protected] · www.weka-ag.ch hae taen millions of proteins in an ordered grid-lie structure. a n d t h e fi r s t f r a g m e nt s c r e e n l a u n c h e d. I n p a r a l le l, t h e t e a m approimately X-ray radiation bright enough for the rapid analysis of had been maing a series of samples to send to a company years protein structures can only be produced by a synchrotron in Oxford called xscientia, hich has set up an AI platform ARCA Flow Group worldwide: Competence in valves, pumps & cryogenics CERN COURIER MUNE

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FEATURE MAGNET TECHNOLOGY TAMING THE SUPERCONDUCTORS The imminent deployment of accelerator magnets based on the superconductor

Nb3 Sn for t he h ig h-lum i nosit y LHC ser ves as a spr i ngb oa rd to f ut ure acceler ator OF TOMORROW mag net s for f unda ment a l e x plor at ion, w r ites Luc a Bot t ur a.

he steady increase in the energy of colliders during Development the past 40 years, which has fuelled some of the One of the 11 T

greatest discoveries in particle physics, was pos- Brice/CERN M niobium-tin T Rayner/CERN M sible thanks to progress in superconducting materials and dipoles for the accelerator magnets. The highest particle energies have HL-LHC, pictured been reached by proton–proton colliders, where beams of at CERN’s Large high-rigidity travelling on a piecewise circular trajectory Magnet Facility r e q u i r e m a g n e t ic fie ld s l a r g e l y i n e x c e s s o f t h o s e t h atcan in Januar y. be produced using resistive electromagnets. Starting from the Tevatron in 1983, through HERA in 1991, RHIC in 2000 a n d fi n a l l y t h e L HC i n 2008,large-scale al hadron colliders were built using superconducting magnets. L a r g e s up e rc o n d uc t i n g m a g n e t s for d e t e c t or s a r e ju s t a s important to high-energy physics experiments as beamline magnets are to particle accelerators. In fact, detector mag- nets are where superconductivity took its stronghold, right from the infancy of the technology in the 1960s, with major installations such as the large bubble-chamber solenoid at Argonne National Laboratory, followed by the giant BEBC solenoid at CERN, which held the record for the highest stored energy for many years. A long line of superconducting magnets has provided the magnetic fields for detectors of all large-scale high-energy physics colliders, with the most r e c e nt a n d l a r g e s t r e a l i s at io n b e i n g t h e L HC e x p e r i m e nt s, CMS and ATL AS.

Optimisation All past accelerator and detector magnets had one thing in common: they were built using composite Nb–Ti/Cu wires and cables. Nb–Ti is a ductile alloy with a critical field of 14.5 T and critical temperature of 9.2 K, made from almost

equal parts of the two constituents. It was discovered to be Wired A Nb3 Sn cable, showing the single strands and the glass-fibre insulation, partially unwrapped. superconducting in 1962 and its performance, quality and dipoles will be substituted by dipoles of shorter length and cost have been optimised over more than half a century Future Circular Collider design study (FCC), both at CERN, q u a d r up ole s, w it h fie ld le v e l s at t h e c oi l i n t h e r a ngeof12 T higher field, approximately 11 T. As described earlier, suc h of research, development and large-scale industrial pro- together with studies and programmes outside Europe, such in the interaction regions. These quadrupoles, currently fields require the use of new materials. For theHL-LHC , t h e duction. Indeed, it is unlikely that the performance of the as the Super proton–proton Collider in China (SppC) or the b e i n g b u i lt a n d t e s t e d at C E R N a n d Fe r m i l a b (s e e p 7), a r e t h e material of choice is the intermetallic compound of niobium

LHC dipole mag nets, oper ated so far at 7.7 T and expected past studies of a Very Large Hadron Collider at Fermilab main fruit of the 10-year US-DOE L HC A c c e le r at or Re s e a rc h and tin Nb3Sn, which was discovered in 1954. Nb 3Sn has to reach nominal conditions at 8.33 T, can be surpassed and the US–DOE Muon Accelerator Program (see p7). This Program (US–LARP) – a joint venture between CERN, a critical field of about 30 T and a critical temperature of using the same superconducting material, or any foreseeable requires that we turn to other superconducting materials Brookhaven National Laboratory, Fermilab and Lawrence a b o ut 18 K, outperforming Nb–Ti by a factor of two. Though THE AUTHOR improvement of this alloy. and novel magnet technology. Berkeley National Laboratory. In addition, the increased discovered before Nb–Ti, and exhibiting better performance, Luca Bottura And yet, approved projects and studies for future circular b e a m i nt e n s it y c a l l s for c ol l i m at or s t o b e i n s e r t e d i n lo c a- Nb Sn has not been used for accelerator magnets so far is head of the 3 CERN magnets, machines are all calling for the development of supercon- The HL-LHC springboard t io n s w it h i n t h e L HC “d i s p e r s io n s up pr e s s or”, t h e p or t io n o f because in its final form it is brittle and cannot withstand superconductors ducting magnets that produce fields beyond those pro- To reach its main objective, to increase the levelled LHC the accelerator where the regular magnet lattice is modified large stress and strain w it hout special precaut ions.

and cryostats duced for the LHC. These include the High-Luminosity lu m i n o s it y at AT L A S a n d C M S, a n d t h e i nt e g r at e d lu m i n o s it y to ensure that off-momentum p a r t ic le s a r e c e nt e r e d i n t h e In fact, Nb3Sn was one of the candidate materials group. LHC (HL-LHC), which is currently taking shape, and the by a factor of 10, the HL-LHC requires very large-aperture interaction points. To gain the required space, standard arc considered for the LHC in the late 1980s and mid 1990s.

34 CERN COURIER MAY/JUNE 2020 CERN COURIER MAY/JUNE 2020 35

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FEATURE MAGNET TECHNOLOGY FEATURE MAGNET TECHNOLOGY

20 Fermilab

eRMC HD1a HD1b RMC HD2 D20 FRESCA2 (100 mm) 15 (50 mm) RD3b (36 mm) SMC11T MDPCT1(60 mm) CERN-PHOTO-202002-038-5 MBHDP101 (60 mm) RT1 CERN/ELIN SMC3a MBHSP102 (60 mm) (50 mm) MBHSP02 10 D10 MSUT RD3c (60 mm) (50 mm) HL-LHC 11T

field (T) (50 mm)

LHC BNL 5 HERA Tevatron RHIC

0 1970 1980 1990 2000 2010 2020 2030 year

Fig. 1. Record fields attained with Nb 3Sn dipole magnets of various configurations and dimensions, and either at liquid (4.2 K, red) or superfluid (1.9 K, blue) helium temperature. Solid symbols are short (< 1 m) demonstrator “racetrack s” with no bore, while open symbols are short models and long magnets with bore. For comparison, superconducting colliders past and present are shown as triangles.

enhanced racetrack model coil (eRMC), developed in the framework of the FCC study. The setup, which consists of Po w e r c ouple Already at that time it was demonstrated that accelerator peratures 1000 °C lower. The superconducting wire also two racetrack coils assembled without mid-plane gap (see

Nb3Sn 11 T dipoles magnets could be built with Nb3Sn, but it was also clear that changes its dimensions by a few percent, which is orders of “Racetrack demo” image on p38), produced a 16.36 T central for the HL-LHC the technology was complex, with a number of critical steps, magnitude larger than the dimensional accuracy requested field at 1.9 K and a 16.5 T peak field on the coil, which is the undergoing tests and not ripe for large-scale production. A good 20 years for fie ld q u a l it y a n d t h e r e for e mu s t b e pr e d ic t e d a n d acom- highest ever reached for a magnet of this configuration. at CERN’s SM18 of progress in basic material performance, cable develop- modated for by appropriate magnet and tooling design. The Cos-theta 1 The MDP “cos-theta 1” dipole accelerator The magnet was also tested at 4.5 K and reached a field of facility in ment, magnet engineering and industrial process control finished coil, even if it is made solid by the polymer cast, magnet at Fermilab, which achieved a field of 14.1 T ab out 16.3 T (see p7). These results send a positive signal for February. was necessary to reach the present state, during which still remains stress and strain sensitive. The level of stress (the highest ever achieved for such a device at an operational the feasibility of next-generation hadron colliders.

time the success of the production of Nb3Sn for the ITER that can be tolerated without breakage can be up to 150 MPa, temperature of 4.5 K) in 2019. A field of 16 T seems to be the upper limit that can be

fusion experiment has given confidence in the credibility to be compared to the electromagnetic stress of optimised reached with a Nb3Sn accelerator magnet. Indeed, though of this material for large-scale applications. As a result, magnets operating at 12 T that can reach levels in the range of necessary development, and the open technology issues, the conductor performance can still be improved, as demon-

magnet experts are now convinced that Nb3Sn technology of 100 MPa. This does not leave much headroom for engi- to allow the next jump. Beyond its prime physics objective, strated by recent results obtained at the National High i s s u ffic ie nt l y m at u r e t o s at i s f y t h e c h a l le n g i n g fie ld le vels neering margins and manufacturing tolerances. Finally, the HL-LHC is therefore the springboard to the future of M a g n e t ic F ie ld L a b or at or y (N H M F L), O h io St at e Un i v e r s it y required by the HL-LHC. protecting high-field magnets from quenches, with their high-field accelerator mag nets. and Fermilab within the scope of the US-MDP, this is the large stored energy, requires that the protection system point at which the material itself will run out of steam. A difficult recipe has a very fast reaction – three times faster than at the LHC Climb to higher peak fields As for any other superconductor, the

The present manufacturing recipe for Nb3Sn acceler- – and excellent noise rejection to avoid false trips related For future circular colliders, the target dipole field has critical current density drops as the The HL-LHC is ator magnets consists of winding the magnet coil with Nb Sn filaments. been set at 16 T for FCC-hh, allowing proton–proton col- field grows, requiring an increasing to flux jumps in the large 3 the springboard glass-fibre insulated cables made of multi-filamentary lisions at an energy of 100 TeV, while China’s proposed pp amount of material to carry a given wires that contain Nb and Sn precursors in a Cu matrix. In The next jump collider (SppC) aims at a 12 T dipole field, to be followed current. The effect becomes dramatic to the future this form the cables can be handled and plastically deformed The CERN magnet group, in collaboration with the US–DOE b y a 20 T dipole. Are these field levels realistic? And based when approaching a sig nificant frac- without breakage. The coils then undergo heat treatment, laboratories participating in the LHC Accelerator Upgrade on whic h tec hnolog y? tion of the critical field. Akin to Nb-Ti of high-field typically at a temperature of around 650 °C, during which the Project, is in the process of addressing these and other chal- Looking at the dipole fields produced byNb Sn devel- in the region of 8 T, a further field 3 accelerator magnets precursor elements react chemically and form the desired l e n g e s, fi n d i n g s olut io n s s u it a bl e for a m a g n e t pr o d uc t io no opment magnets during the past 40 years (figure 1), fields increase with Nb3Sn beyond 16 T would Magnet Nb3Sn superconducting phase. At this stage, the reacted the scale required for the HL-LHC. A total of six 11 T dipoles up to 16 T have been achieved in R&D demonstrators, require an exceedingly large coil and experts are coil is extremely fragile and needs to be protected from (each about 6 m long) and 20 inner triplet quadrupoles (up to suggesting that the FCC target can be reached. In 2018 an impractical amount of conductor. Reaching the ultimate any mechanical action. This is done by injecting a polymer, 7.5 m long) are in production at CERN and in the US, and the “FRESCA2” – a large-aperture (100 mm) dipole developed performance of Nb Sn, which will be situated between the now convinced 3 which fills the interstitial spaces among cables, and is first mag net s have been tested (see “Power couple” i mage over the past decade through a collaboration between CERN present 12 T a n d t h e e x p e c t e d m a x i mu m o f 16 T, s t i l l r e q u i r e s t h at N b 3Sn subsequently cured to become a matrix of hardened plastic above). And yet, it is clear that we are not ready to extrapolate and CEA-Saclay in the framework of the European Union muc h w or k. T h e t e c h n olo g y i s s ue s id e nt i fie d b y t h e o ng- technology is providing cohesion and support to the cables. such production on a much larger scale, i.e. to the thousands project EuCARD – attained a record field of 14.6 T at 1.9 K ing work on the HL-LHC magnets are exacerbated by the sufficiently The above process, though conceptually simple, has a of magnets required for a possible future hadron collider (13.9 T at 4.5 K). A n o t h e r v e r y r e c e nt r e s u lt, o b t a i n e d i n Ju n e increase in field, electromagnetic force and stored energy. mature to number of technical difficulties that call for top-of-the-line such as FCC-hh. This is exactly why the HL-LHC is so critical 2019, is the successful test at Fermilab by the US Magnet Innovative industrial solutions will be needed, and the satisfy the engineering and production control. To give some examples, t o t h e d e v e lo p m e nt o f h i g h-fie ld m a g n e t s for f ut u r e a cel- Development Programme (MDP) of a “cos-theta” dipole conductor itself brought to a level of maturity comparable challenging the texture of the electrical insulation, consisting of a few erators: not only will it be the first demonstration ofNb 3Sn w it h a n a p e r t u r e o f 60 m m c a l le d M DP C T 1 (s e e “C o s-t h e t a to Nb–Ti in terms of performance, quality and cost. This field levels tenths of mm of glass fibre, needs to be able to withstand magnets in operation, steering and colliding beams, but by 1” i m a g e a b o v e), w h ic h r e a c h e d a fie ld o f 1 4.1 T a t 4.5 K (CERN work is the core of the ongoing FCC magnet-development required by the high-temperature heat-treatment step, but also retain building it on a scale that can be managed at the laboratory Courier S e p t e m b e r/O c t o b e r 2019 p 7). I n Fe br u a r y t h i s y e a r, programme that CERN is pursuing in collaboration with

the HL-LHC dielectric and mechanical properties at liquid-helium tem- level we have a unique opportunity to identify all the areas the CERN magnet group set a new Nb3Sn record with an laboratories, universities and industries worldwide.

36 CERN COURIER MAY/JUNE 2020 CERN COURIER MAY/JUNE 2020 37

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FEATURE MAGNET TECHNOLOGY ADVERTISING FEATURE

Racetrack demo approaching structural material limits. Stored energy

A Nb3 Sn h a s t h e s a m e s q u a r e-d e p e n d e n c e o n t h e fie ld, a n d q ue n ch

demonstrator Perez/CERN J detection and protection in large HTS magnets are still a racetrack dipole spectacular challenge. In fact, HTS magnet engineering Floating into the process measurement technology magnet with no will probably differ so much from the LTS paradigm that bore developed at it is fair to say that we do not yet know whether we have The model BGN/BGF flow metres of Various transducers are available for CERN in the identified all the issues that need to be solved. HTS is the KOBOLD Messring GmbH from the evaluation of the measurement framework of the most exciting class of material to work with; the new world Hofheim, which function in accordance results. In addition to the 4–20 mA Future Circular for br a v e e x pl or e r s. B ut it i s s t i l l t o o e a rl y t o c o u nt o n pr a c- with the float measuring principle, output signal, NAMUR-contacts and Collider study, tical applications, not least because the production cost for make dependable flow measurement HART-protocol, as well as Profibus-PA which reached a this rather complex class of ceramic materials is about two of liquids and gases even in difficult can be selected. There is also a design record peak field of orders of magnitude higher than that of good-old Nb–Ti. application cases possible. The robust with a counter. 16.5 T in February. It is thus logical to expect the near future to be based all-metal devices can also be used for mainly on Nb Sn. With the first demonstration to come 3 metering and monitoring various imminently in the LHC, we need to consolidate the technol- ogy and bring it to the maturity necessary on a large-scale media in addition to flow pr o d uc t io n. T h i s m a y l i k e l y t a k e pl a c e i n s t e p s – e x plor i n g measurement. Various measuring 12 T t e r r it or y fi r s t, w h i le s e e k i n g t h e s olut io n s t o t h echal- ranges, from 0.5 l/h to 130,000 l/h,

lenges of ultimate Nb3Sn performance towards 16 T – and offer an enormous application could take as long as a decade. For China’s SppC, iron-based spectrum, even in high-pressure and HTS has been suggested as a route to 20 T dipoles. This high-temperature areas. The current technology study is interesting from the point of view of measurement value is transferred to the material, but the magnet technology for iron-based the clearly legible display by means of superconductors is still rather far away. magnets without contact and without a Customer-specific production of the M e a n w h i le, nu r t u r e d b y n o v e l id e a s a n d i n n o v at i v e s olu- risk of disconnection. devices makes it possible to use an tions, HTS could grow from the present state of a material o f g r e at p o t e nt i a l t o it s fi r s t a p pl ic at io n s. T h e L HC a l r e ady enormous variety of media-contact uses HTS tapes (based on Bi-2223) for the superconducting materials like various types of stainless part of the current leads. The HL-LHC will go further, by steel, Hastelloy, PTFE, and titanium.

pio n e e r i n g t h e u s e o f M g B 2 to transport the large currents Pipe nominal diametres up to DN 150 required to power the new magnets over considerable dis- also offer comfortable measurements tances (thereby shielding power converters and making without measured flow separation for m a i nt e n a n c e muc h e a s ie r). T h e g r a n d c h a l l e n g e s p o s e d b y very large volumes. Naturally, nearly HTS will likely require a revolution rather than an evolution all process connections are available. As the limit of Nb Sn comes into view, we see history o f m a g n e t t e c h n olo g y, a n d s i g n i fic a nt t e c h n olo g y a d v a nce- 3 The measuring devices can optionally repeating itself: the only way to push beyond it to higher ment leading to large-scale application in accelerators can be equipped with differential pressure fields will be to resort to new materials. Since Nb Sn is only be imagined on t he 25-year hori zon. 3 regulator, backflow stop, idle technically the low-temperature superconductor (LTS) with the highest performance, this will require a shift to Road to the future capability, heating, and double eddy- high-temperature superconductors. There are two important messages to retain from this Due to its special design with a current damping. High-temperature superconductivity (HTS), discovered rather simplified perspective onhigh-field magnets for measuring ring and conical float, a in 1986, is of great relevance in the quest for high fields. accelerators. Firstly, given the long lead times of this guide rod for the float can be omitted, When operated at low temperature (the same liquid-helium technology, and even in times of uncertainty, it is impor- which has tremendous advantages: the range as LTS), HTS materials have exceedingly large critical tant to maintain a healthy and ambitious programme so float has almost no friction loss and the fie ld s i n t h e r a n g e of100 T and above. And yet, only recently that the next step in technology is at hand when criti- danger of contamination in the internal has the material and magnet engineering reached the point cal decisions on the accelerators of the future are due. measurement space is greatly reduced. w h e r e H T S m at e r i a l s c a n g e n e r at e m a g n e t ic fie ld s i n e x c e s The second message is that with such long development A linear characteristic curve also of LTS ones. The first user applications coming to fruition cycles and very specific technology, it is not realistic KOBOLD Messring GmbH results from the optimised form of a r e u lt r a-h i g h-fie ld N M R m a g n e t s, a s r e c e nt l y d e l i v e redby to rely on the private sector to advance and sustain the Nordring 22-24 Br u k e r Bio s pi n, a n d t h e i nt e n s e m a g n e t ic fie ld s r e q u i r e d b y specific demands of HEP. In fact, the business model the float. D-65719 Hofheim/Ts materials science, for example the 32 T all-superconducting of high-energy physics is very peculiar, involving long Tel: 06192/299-0 user facilit y built at NHMFL. investment times followed by short production bursts, In addition to the usual vertical type of The potential Fax: 06192/23398 As for their application in accelerator magnets, the poten- and not sustainable by present industry standards. So, installation (flow from the bottom to of high- tial of HTS to make a quantum leap is enormous. But it without taking the place of industry, it is crucial to secure the top), the measuring device, model Email: [email protected] temperature is also clear that the tough challenges that needed to be critical know-how a n d i n f r a s t r uc t u r e w it h i n t h e fie ld t o BGF, offers the possibility of horizontal super- solved for Nb3Sn will escalate to a formidable level in HTS meet development needs and ensure the long-term future installation or vertical flow from top to conductivity accelerator magnets. The magnetic force scales with the of our accelerators, present and to come.  bottom. The devices can be optionally to make a  s q u a r e o f t h e fie ld pr o d uc e d b y t h e m a g n e t, a n d for H TSthe This is an updated version of an article published recen­ equipped with a spring stop and an quantum leap problem will no longer be whether the material can carry tly in a special supplement about magnet technology: attenuation. This buffers pressure is enormous the super-currents, but rather how to manage stresses cerncourier.com/p/in-focus/magnet-technology. spikes and prevents indicator flutter. www.kobold.com

38 CERN COURIER MAY/JUNE 2020

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FEATURE MUON COLLIDER

PROVIDING CUTTING-EDGE SOLUTIONS FOR A PRECISELY KNOWN, STABLE AND RELIABLE BEAM.

BEAM DIAGNOSTICS LLRF CONTROLS RF GENERATION & DISTRIBUTION RF DIGITIZERS & CURRENT METERS

Instrumentation Technologies, d.o.o. / Velika pot 22, SI-5250 Solkan, Slovenia / e: [email protected] / w: www.i-tech.si

Background reduction A model of the machine–detector interface for a muon collider. The interaction point is on the left. The principal detector components are not visualised (teal region). The geometry, material distributions and magnetic fields are optimised to protect components from the high levels of beam-induced background, such as muon decays, which induce electromagnetic showers (green). (Credit: N V Mokhov) SKETCHING OUT

Magnets for research A MUON COLLIDER and medicine A high-energy muon collider is receiving renewed attention as a possible

scanditronix-magnet.se frontier-exploration machine. Daniel Schulte, Nadia Pastrone and Ken Long describe the possible paths ahead.

igh-energy particle colliders have proved to be particle physics. An electron–positron Higgs factory indispensable tools in the investigation of the that allows precision measurements of the Higgs boson’s THE AUTHORS nature of the fundamental forces. The LHC, at couplings and the Higgs potential seems to have garnered H Daniel Schulte which the discovery of the Higgs boson was made in 2012, consensus as the best machine for the near future. The CERN, is a prime recent example. Several major projects have question is: what type will it be? Nadia Pastrone been proposed to push our understanding of the universe Today, mature options for electron–positron colliders INFN Torino and once the LHC reaches the end of its operations in the late exist: the Future Circular Collider (FCC-ee) and the Compact Ken Long 2030s. These have been the focus of discussions for the Linear Collider (CLIC) proposals at CERN; the International Imperial College soon-to-conclude update of the European strategy for Linear Collider (ILC) in Japan; and the Circular Electron– London and STFC.

CERN COURIER MAY/JUNE 2020 41

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FEATURE MUON COLLIDER FEATURE MUON COLLIDER

Fig. 1. Schematic Source: arXiv:1901.06150 Source:

layouts of the two Nature proton driver front end cooling acceleration collider ring x = 0.16 m

muon-collider 2 x = 0.0 m 578 concepts: the + 53

μ (T) z 0 Hall probes proton-driven ECoM: B scheme explored Higgs Factory –2 by MAP (top) and μ to

10 TeV ε = 4 mm

the more recent ~ buncher →

buncher 100 ε = 6 mm SC linac LEMMA proposal combiner →+ capture sol. merge 6D cooling 6D cooling bunch μ μ

phase rotator accelerators: final cooling ε = 10mm accumulator (bottom). decay channel (x) (mm) MW-class target charge separator 50 initial 6D cooling

linacs, RLA or FFAG, RCS σ

0 Low EMmittance Muon positron linac positron acceleration collider ring Accelerator (LEMMA): ring 15 z (m) 20 11 + – 10 μ pairs/sec from e e + μ ECoM: MICE upstream spectrometer solenoid focus coil downstream spectrometer solenoid interactions. The small production TOF2 TOF0 TOF1 emittance allows lower overall charge 10s of TeV positron linac in the collider rings – hence, lower μ backgrounds in a collider detector

and a higher potential centre-of-mass rings → → Ckov Ckov

target + energy while mitigating neutrino accelerators: μ μ A B 100 KW 0 1 m KL EMR radiation from muon decays. isochronous linacs, RLA or FFAG, RCS diffuser upstream tracker LH2 absorber downstream tracker

Fig. 2. A sketch of the MICE apparatus. The modelled field Bz is shown on the beam axis (black line) and at 160 mm from the Positron Collider (CEPC) in China. FCC-ee offe r s v e r y h i gh rather quick in producing, accelerating and colliding the axis (green line) in the horizontal plane. The readings of Hall probes situated at 160 mm from the beam axis are also shown. luminosities at the required centre-of-m a s s e n e r g ie s. Ho w- muons; this rapid handling provides the main challenges Vertical lines indicate the positions of the tracker stations (dashed) and the absorber (dotted). The nominal r.m.s. beam width e v e r, t h e m a x i mu m e n e r g y t h at c a n b e r e a c h e d i s l i m it e d b y of such a project. σ(x) is calculated assuming a nominal input beam and using linear beam-transport equations. The beams have minimum size the emission of synchrotron radiation in the collider ring, and hence maximum divergence inside the focus coil, to maximise cooling. and corresponds to a centre-of-m a s s e n e r g y o f 365 G eV for a Precision and discovery 100 km-circumference machine. Linear colliders accelerate The development of a muon collider is not as advanced as tion of the quartic self-coupling t h at i s s i g n i fic a nt l y b e t t e r p h y s ic s, m a c h i n e a n d d e t e c t or s t ud ie s c a n n o t d o w it h o ut. particles without the emission of synchrotron radiation, the other lepton-collider o p t io n s t h at w e r e s u b m it t e d t o t h e t h a n w h at i s c u r r e nt l y c o n s id e r e d at t a i n a ble at o t h e r f ut u r e So far, two concepts have been proposed for a muon and hence can reach higher energies. The ILC would initially European strategy process. Therefore the unique potential colliders. Owing to the muon’s greater mass, the coupling c ol l id e r (fi g u r e 1). T h e fi r s t d e s i g n, d e v e lo p e d b y M A P, isto operate at 250 GeV, extendable to 1 TeV, while the highest of a mu lt i-TeV muon collider deserves a strong commit- of t he muon to t he Higgs boson is enhanced by a factor of shoot a proton beam into a target to produce pions, many energy proposal, CLIC, has been designed to reach 3 TeV. m e nt t o f u l l y d e m o n s t r at e it s fe a s i bi l it y. E x t e n s i v e s t ud ie s about 104 compared to the electron–Higgs coupling. To of which decay into muons. This cloud of muons (with However, there are two principal challenges that must be submitted to the strategy update show that a muon collider e x ploit t h i s, pr e v io u s s t ud ie s h a v e a l s o i n v e s t i g at e d a muo n p o s it i v e a n d n e g at i v e c h a r g e) i s c a p t u r e d a n d a n io n i s at io n overcome to go to higher energies with a linear machine: in the mu lt i-TeV energ y r a nge would be compet it ive bot h collider operating at a centre-of-mass energy of 126 GeV c o ol i n g s y s t e m o f a t y p e fi r s t i m a g i n e d b y B ud k e r r a pid ly first, the beam has to be accelerated to full energy in a as a precision and as a discovery machine, and that a full (the Higgs pole) to measure the Higgs-boson line-shape. cools the muons from the showers to obtain a dense beam. s i n g le p a s s a g e t h r o u g h t h e m a i n l i n a c; a n d, s e c o n d, it c a n effort by the community could demonstrate that a muon T h e s p e c i fic at io n s for s uc h a m a c h i n e a r e d e m a n d i n gasit The muons are cooled in a chain of low-Z absorbers in only be used once in a single collision. At higher energies c ol l id e r o p e r at i n g at a fe w TeV c a n b e r e a d y o n a t i m e s c a le r e q u i r e s k n o wle d g e o f t h e beam-energy s pr e a d at t h e le v e l which they lose energy by ionising the matter, reducing t h e l i n a c h a s t o b e lo n g e r (a r o u n d 50 km for a 1 TeV IL C a n d of about 20 years. While the full physics capabilities at high of a few par ts in 10 5. their phase space volume; the lost energy would then be a 3 TeV C L IC) a n d i s t h e r e for e m or e c o s t l y, w h i le t h e s i n g le energies remain to be quantified, and provided the beam replaced by acceleration. This is so far the only concept collision of the beam also limits the luminosity that can energ y and detector resolut ions at a muon collider can be Half a century of ideas t h at c a n a c h ie v e c o ol i n g w it h i n t h e t i m e f r a m e o f t h e muo n be ac hieved for a reasonable power consumpt ion. maintained at the parts-per-mille level, the number of The idea of a muon collider was first introduced 50 years lifetime. The beams would be accelerated in a sequence Higgs bosons produced would allow the Higgs’ couplings ago by Gersh Budker and then developed by Alexan- of linacs and rings, and injected at full energy into the Beating the lifetime t o fe r m io n s a n d b o s o n s t o b e m e a s u r e d w it h e x t r a ord i n a r y der Skrinsky and David Neuffer until the Muon Collider collider ring. A fully integrated conceptual design for the An ingenious solution to overcome these issues is to precision. A muon collider operating at lower energies, C ol l a b or at io n b e c a m e a for m a l e nt it y i n 1997, w it h m or e t h a n M AP concept remains to be developed. replace the electrons and positrons with muons and such as those for the proposed FCC-ee (250 a n d 365 G eV ) or 100 p h y s ic i s t s f r o m 20 i n s t it ut io n s i n t h e US a n d a fe w m or e The alternative approach to a muon collider, proposed anti-muons. In a muon collider, fundamental particles stage-one C L IC (380 G eV ) m a c h i n e s, h a s n o t b e e n s t ud ie d i n from Russia, Japan and Europe. Brookhaven’s Bob Palmer in 2013 by Mario Antonelli of INFN-LNF and Pantaleo that are not constituents of ordinary matter would col- detail since the beam-induced b a c k g r o u n d w i l l b e h a r s h e r was a key figure in driving the concept forward, leading R a i m o n d i o f t h e E SR F, a v oid s a s p e c i fic c o ol i n g a p p a r at u s. lide for the first time. Being 200 times heavier than the and careful optimisation of machine parameters would the outline of a “complete scheme” for a muon collider in Instead, the Low Emittance Muon Accelerator (LEMMA) It was The unique electron, the muon emits about two billion times less be required to reach the needed luminosity. Moreover, a 2007. Exploratory work towards a muon collider and neu- scheme would send 45 GeV positrons into a target where only when synchrotron radiation. Rings can therefore be used to muon collider generating a centre-of-m a s s e n e r g y o f 10 TeV t r i n o f a c t or y w a s a l s o c a r r ie d o ut at C E R N a ro u n d t h e t u r n they collide with electrons to produce muon pairs with potential of the Muon a c c e le r at e muo n b e a m s e ffic ie nt l y a n d t o br i n g t h e m i nto or more and with a luminosity of the order of 1035 cm–2 s–1 of the millennium. It was only when the Muon Accelerator a very small phase space (the energy of the electron and a multi-TeV Accelerator c ol l i s io n r e p e at e d l y. A l s o, m or e t h a n o n e e x p e r i m e nt c a n would allow a direct measurement of the trilinear and Program (MAP), directed by Mark Palmer of Brookhaven, positron in the centre-of-mass frame are small, so little muon collider Program be served simultaneously to increase the amount of data quadrilinear self-couplings o f t h e H i g g s b o s o n, e n a bl i n g a was formally approved in 2011 in the US, that a systematic transverse momentum can be generated). The challenge deserves collected. Provided the technology can be mastered, it pr e c i s e d e t e r m i n at io n o f t h e s h a p e o f t h e H i g g s p o t e nt i a l. e ffor t s t a r t e d t o d e v e lo p a n d d e m o n s t r at e t h e c o n c e p t sand w it h L E M M A i s t h at t h e pr o b a bi l it y for a p o s it r o n t o pr o d uc e was formally a strong appears possible to reach a ratio of luminosity to beam W h i le t h e pr e c i s io n o n H i g g s m e a s u r e m e nt s a c h ie v a ble at critical technologies required to produce, capture, con- a muon pair is exceedingly low, requiring an unprecedented approved in commitment power that increases with energy. The catch is that muons muo n c ol l id e r s i s n o t y e t s u ffic ie nt l y e v a lu at e d t o p e r for ma dition, accelerate and store intense beams of muons for positron-beam current and inducing a high stress in the 2011 in the to fully live on average for 2.2 μs, which leads to a reduction in the comparison to other future colliders, theorists have recently a muon collider on the Fermilab site. Although MAP was target system. The muon beams produced would be cir- US that a demonstrate number of muons produced by about an order of magnitude shown that a muon collider is competitive in measuring the wound down in 2014, it generated a reser voir of expertise c u l at e d a b o ut 1000 t i m e s, l i m it e d b y t h e muo n l i fe t i m e, i n systematic its feasibility b e for e t h e y e nt e r t h e s t or a g e r i n g. O n e t h e r e for e h a s t o b e t r i l i n e a r H i g g s c o upl i n g a n d t h at it c o u ld a l lo w a d e t e r m i n a- and enthusiasm that the current international effort on a ring collecting muons produced from as many positron effort started

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FEATURE MUON COLLIDER FEATURE MUON COLLIDER D Lucchesi D Lucchesi 53 results demonstrating the feasibility of the technique (CERN material can be placed, or designs where the magnets have ISIS user runs 578 2017/02 and 2017/03 4-140 6-140 10-140 MAUS-v3.3.2 Courier March/April 2020 p7). Since muons produced from no superconductor in the plane of the beam. Future mag-

MICE MICE MICE measured al. et Nature simulated proton interactions in a target emerge in a rather undis- nets based on high-temperature superconductors could 1.0 empty ciplined state, MICE set out to show that their transverse also help to improve the robustness of the bends against Source: 0.5 LH2 phase-space could be cooled by passing the beam through this problem since they can tolerate a higher heat load. MICE MICE MICE an energy-absorbing material and accelerating structures Other systems necessary for a muon collider are only 1.0 full embedded within a focusing magnetic lattice – all before seemingly more conventional. The ring that accelerates the LH 0.5 2 t h e muo n s h a v e t i m e t o d e c a y. For t h e s c h e m e t o wor k, t h e beam to the collision energy is a prime example. It has to

MICE MICE MICE cooling (squeezing the beam in transverse phase space) ramp the beam energy in a period of milliseconds or less,

number in 1.0 no due to ionisation energy loss must exceed the heating which means the beam has to circulate at very different number out absorber 0.5 due to multiple Coulomb scattering within the absorber. energies through the same magnets. Several solutions Materials with low multiple scattering and a long radiation are being explored. One, featuring a so-called fixed-field MICE MICE MICE length, such as liquid hydrogen and lithium hydride, are alternating-gradient ring, uses a complicated system of LiH therefore ideal. magnets that enables particles at a wider than normal range MICE, which was based at the ISIS neutron and muon of energies to fly on different orbits that are close enough source at the Rutherford Appleton Laboratory in the UK, t o fit i nt o t h e s a m e m a g n e t a p e r t u r e s. A n o t h e r p o s s ibility 10 20 30 40 20 40 20 40 60 amplitude (mm) was approved in 2005. Using data collected in 2018, the is to use a fast-ramping synchrotron: when the beam is MICE collaboration was able to determine the distance injected at low energy it is kept on its orbit by operating the a very high occupancy in the first layers of the tracking Fig. 5. Fig. 3. Muons that pass through MICE are seen to migrate from high to low of a muon from the centre of the beam in 4D phase space b e n d i n g m a g n e t s at lo w fie ld. T h e b e a m i s t h e n a c c e le r ated system, which impacts the detector performance. Since A simulation amplitudes (a measure of the distance of a particle from the centre of transverse (its so-called amplitude or “single-particle emittance”) and the strength of the bends is increased accordingly until the arrival time in each sub-detector is asynchronous with indicates that phase space), with an enhancement of the number at low amplitudes providing both before and after it passed through the absorber, from the beam can be extracted into the collider. It is very chal- respect to the beam crossing, due to the different paths Higgs-boson evidence of ionisation cooling. The effect in a single absorber is stronger for high which it was possible to estimate the degree of cooling lenging to ramp superconducting magnets at the required taken by the beam-induced background and the muons, decays to a initial-emittance beams (10 mm) than for lower and intermediate configurations that had occurred. The results (figure 3) demonstrated speed, however. Normal-conducting magnets can do better, new-generation 4D silicon sensors that allow exploita- b-quark pair can (4 and 6 mm). The results are shown for beams with a momentum of 140 MeV/c. that ionisation cooling occurs with a liquid-hydrogen or but their magnetic field is limited. As a consequence, the tion of the time distribution will be needed to remove a be reconstructed at lithium-hydride absorber in place. Data from the exper- accelerator ring has to be larger than the collider ring, significant fraction of the background hits. a muon collider iment were found to be well described by a Geant4-based which can use superconducting magnets at full strength despite the harsh

N V Mok hov simulation, validating the designs of ionisation cooling without the need to ramp them. Systems that combine static Energy expansion environment: channels for an eventual muon collider. The next impor- superconducting and fast-ramping normal-conducting It was recently demonstrated, by a team supported by the two b-jets are tant step towards a muon collider would be to design and bends have been explored by the MAP collaboration. In INFN and Padova University in collaboration with MAP identifiable (red build a cooling module combining the cavities with the these designs, the energy in the fields of thefast-ramping researchers, that state-of-the-art detector technology dots) among the magnets and absorbers, and to achieve full “6D” cooling. bends will be very high, so it is important that the energy for tracking and jet reconstruction would make one of beam-induced This effort could profit from tests at Fermilab of accel- is recuperated for use in a subsequent accelerating cycle. the most critical measurements at a muon collider – the background. erating cavities that can operate in a very high magnetic This requires a very efficientenergy-recovery system vector-boson fusion channel μ+μ– → (W*W*) ν ν– → H ν ν–, – field, and also from thenormal-conducting cavity R&D which extracts the energy after each cycle and reuses with H → b b – feasible in this harsh environment, with u n d e r t a k e n for t h e C L IC s t ud y, w h ic h p u s h e d a c c e le r at i n g it for the next one. Such a system, called POPS (“power a high level of precision, competitive to other proposed gradients to the limit. for PS”), is used to power the magnets of CERN’s Proton machines (figure 5). A muon collider could in principle Synchrotron. The muon collider, however, requires more expand its energy reach to several TeV with good luminos- Collider ring stored energy and much higher power flow, which calls ity, allowing unprecedented exploration in direct searches The collider ring itself is another challenging aspect of for novel solutions. and high-precision tests of Standard Model phenomena, a muon collider. Since the charge of the injected beams in particular the Higgs self-couplings. Fig. 4. A model with tungsten nozzles (yellow) on each side of the interaction point decreases over time due to the random decays of muons, High occupancy The technology for a muon collider also underpins a and tungsten (purple) masks in interconnect regions. The collider sub-detectors and s up e rc o n d uc t i n g m a g n e t s w it h t h e h i g h e s t p o s s i ble fie ld Muon decays also induce the presence of a large amount of so-called neutrino factory, in which beams of equal numbers iron-concrete shielding around the magnets are also shown, along with particle are needed to minimise the ring circumference and thus background in the detectors at a muon collider – a factor of electron and muon neutrinos are produced from the decay tracks (> 1 GeV) for several decays of both muon beams. maximise the average number of collisions. A larger muon that must be studied in detail since it strongly depends on of muons circulating in a storage ring – in stark contrast e n e r g y m a k e s it h a rd e r t o b e n d t h e b e a m a n d t hu s r e q u i r e s the beam energy at the collision point and on the design of to the neutrino beams used at T2K and NOvA, and envis- bunches as possible before they are accelerated and col- a larger ring circumference. Fortunately, the lifetime of the the interaction region. The background particles reach- aged for DUNE and Hy per-K, which use neutrinos from the lided in a fashion similar to the proton-driven scheme of muon also increases with its energy, which fully compen- ing the detector are mainly produced by the interactions decays of pions and kaons from proton collisions on a fixed MAP. The low emittance of the LEMMA beams potentially sates for this effect. Dipole magnets with a field of 10.5 T between the decay products of the muon beams and the target. In such a facility it is straightforward to tune the allows the use of lower muon currents, easing the chal- would allow the muons to survive about 2000 turns. Such machine elements. Their type, flux and characteristics neutrino-beam energy because the neutrinos carry away a lenges of operating a muon collider due to the remnants of m a g n e t s, w h ic h a r e a b o ut 20% m or e p o w e r f u l t h a n t h o s e therefore strongly depend on the machine lattice and substantial fraction of the muon’s energy. This, combined

the decaying muons. The initial LEMMA scheme offered in the LHC, could be built from niobium-tin (Nb3Sn) a s u s e d the configuration of the interaction point, which in turn with the excellent knowledge of the beam composition and limited performance in terms of luminosity, and further in the new magnets for the HL-LHC (see p34). depends on the collision energy. The background particles energy spectrum that arises from the precise knowledge studies are required to optimise all parameters of the source The electrons and positrons produced when muons (mainly photons, electrons and neutrons) may be produced of muon-decay characteristics, makes a neutrino factory before capture and fast acceleration. With novel ideas and a decay pose an additional challenge for the magnet tens of metres upstream of the interaction point. To mit- an attractive place to measure neutrino oscillations with dedicated expert team, LEMMA could potentially be shown design. The decay products will hit the magnets and can igate the effects of thebeam-induced background inside great precision and to look for oscillation phenomena that to be competitive with the MAP scheme. lead to a quench (whereby the magnet suddenly loses the detector, tungsten shielding cones, called nozzles, are are outside the standard, three-neutrino-mixing paradigm. Concerning the ambitious muon ionisation-cooling its superconductivity, rapidly releasing an immense proposed in this configuration and their opening angle has One proposal – nuSTORM, an entry-level facility proposed complex (figure 2), which is the key challenge of MAP’s amount of stored energy). It is therefore important to to be optimised for a specific beam energy, which affects for the precise measurement of neutrino-scattering and the proton-driven muon-collider scheme, the Muon Ionization protect the magnets. The solutions considered include t h e d e t e c t or a c c e p t a n c e (s e e fi g u r e 4). D e s pit e t h e s e m iti- search for sterile neutrinos – can provide the ideal test-bed C o ol i n g E x p e r i m e nt (M IC E) c ol l a b or at io n r e c e nt l y p u bl i s h e d the use of large-aperture magnets in which shielding gations, a large particle flux reaches the detector, causing for the technologies required to deliver a muon collider.

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FEATURE MUON COLLIDER SUPERCON, Inc. Muon-based facilities have the potential to provide to produce localised radiation that can reach a fraction lepton–antilepton collisions at centre-of-mass energies of natural-radiation levels. Beam wobbling, whereby the Superconducting Wire and Cable in excess of 3 TeV and to revolutionise the production of lattice is modified periodically so that the neutrino flux neutrino beams. Where could such a facility be built? A pointing to Earth’s surface is spread out, is one of the Standard and Specialty designs are available to meet your most demanding 14 TeV muon collider in the 27 km-circumference LHC promising solutions to alleviate the problem, although it superconductor requirements. tunnel has recently been discussed, while another option requires further studies. is to use the LHC tunnel to accelerate the muons and con- A muon collider would be a unique lepton-collider facil- SUPERCON, Inc. has been producing niobium-based superconducting wires and cables for half a century. struct a new, smaller tunnel for the actual collider. Such a ity at the high-energy frontier. Today, muon-collider We are the original SUPERCON – the world’s first commercial producer of niobium-alloy based wire and facility is estimated to provide a physics reach comparable concepts are not as mature as those for FCC-ee, CLIC, to a 100 TeV circular hadron collider, such as the proposed ILC or CEPC. It is now important that a programme is cable for superconducting applications. Future Circular Collider, FCC-hh. A LEMMA-like positron established to prove the feasibility of the muon collider, driver scheme with a potentially lower neutrino radia- address the key remaining technical challenges, and pro- Standard SC Wire Types Product Applications tion could possibly extend this energy range still further. vide a conceptual design that is affordable and has an NbTi Wires Magnetic Resonance Imaging Fermilab, too, has long been considered a potential site acceptable power consumption. The promises for the very Nb3Sn —Bronze Nuclear Magnetic Resonance for a muon collider, and it has been demonstrated that the high-energy lepton frontier suggests that this opportunity Nb3Sn —Internal Tin High Energy Physics footprint of a muon facility is small enough to fit in the should not be missed.  CuNi resistive matrix wires SC Magnetic Energy Storage existing Fermilab or CERN sites. However, the realistic performance and feasibility of such a machine would have Further reading Fine diameter SC Wires Medical Therapeutic Devices t o b e c o n fi r m e d b y a d e t a i le d fe a s i bi l it y s t ud y id e nt i fying D Alesini et al. 2019 arXiv:1905.05747. Aluminum clad wire Superconducting Magnets and Coils The muon the required R&D to address its specific issues, especially N Bartosik et al. 2020 arXiv:2001.04431. Wire-in-Channel Crystal Growth Magnets collider would the compatibility of existing facilities with muon decays. M Chiesa et al. 2020 arXiv:2003.13628. Innovative composite wires Scientific Projects be a unique Minimising off-site neutrino radiation is one of the main J P Delahaye et al. 2019 arXiv:1901.06150. lepton-collider challenges to the design and civil-engineering aspects MICE Collaboration 2020 Nature 578 53. facility at the of a high-energy muon collider because, while the inter- Muon Accelerators for Particle Physics (MUON) Special “We deliver superconductivity!” high-energy action probability is tiny, the total flux of neutrinos is issue of J. Instrum (https://iopscience.iop.org/ frontier sufficiently high in a very small area in the collider plane journal/1748-0221/page/extraproc46). Contact us at [email protected]

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Bridging Europe’s neutron gap ILL The recent closure of reactors means making the most of existing facilities while preparing accelerator-based sources, says Helmut Schober.

In increasing its focus towards averting environmental disaster and maintaining economic competitiveness, both the Euro- pean Union and national governments Reactor neutrons are looking towards green technologies, The Institut such as materials for sustainable energy Laue-Langevin in Early Bird Registration: 30 June 2020 production and storage. Such ambitions Grenoble. rely on our ability to innovate – powered by Europe’s highly developed academic Helmut Schober network and research infrastructures. SINQ facility in Switzerland – are fully (CANS). Contrary to spallation sources is director of the Europe is home to world-leading neu- exploited. These facilities have been that produce neutrons by bombarding Institut Laue- tron facilities that each year are used by upgraded in recent years, but their heavy nuclei with high-energy protons, Langevin and chair more than 5000 researchers across all long-term viability must be secured. This CANS rely on nuclear processes that can be of the League of fields of science. Studies range from the is not to be underestimated. For example, triggered by proton bombardment in the advanced European dynamics of lithium-ion batteries, to 20% of the ILL’s budget relies on the con- 5 to 50 MeV range. While these processes Neutron Sources. developing medicines against viral dis- tributions of 10 scientific members that are less efficient than spallation, they eases, in addition to fundamental stud- must be renegotiated every five years. The allow for a more compact target and mod- ies such as measurements of the neutron rest is provided by the ILL’s three associate erator design. Examples of this scheme are electric-dipole moment. Neutron science countries (France, Germany and the UK). SONATE, currently under development at holds enormous potential at every stage of T h e l o s s o f o n e o f it s m aj or s c i e n t i fic m e m- CEA-Saclay and the High Brilliance Source innovation, from basic research through bers, even only partially, would severely being pursued at Jülich. CANS must now be to commercialisation, with at least 50% of threaten the ILL’s upgrade capacity. brought to maturity, requiring carefully publications globally attributed to Euro- planned business models to identify how pean researchers. Yet, just as the demand Accelerator sources they can best reinforce the ecosystem of for neutron science is growing, access to The European Spallation Source (ESS) neutron science. facilities is being challenged. under construction in Sweden, which It is also important to begin strate- Three of Europe’s neutron facilities was conceived more than 20 years ago, gic discussions that aim beyond 2030, closed in 2019: BER II in Berlin; Orphée must become a fully operating neutron including the need for powerful new in Paris; and JEEP II outside Oslo. The facility at the earliest possible date. This national sources that will complement rationale is specific to each case. There was initially foreseen for 2019, now sched- the ESS. Continuous (reactor) neutron are lifespan considerations due to finan- uled for 2023. Europe must ask itself why sources must be part of this because many cial resources, but also political con- b u i l d i n g l a r g e s c i e nt i fic f a c i l it i e s s u c h as applications, such as the production of siderations when it comes to nuclear ESS, or FAIR in Germany, takes so long, neutron-rich isotopes for medical pur- installations. The potentially negative despite significant strategic planning poses, require the highest time-averaged consequences of these closures must be (e.g. via ESFRI) and sophisticated project neutron flux. Such a strategic evaluation is carefully managed to ensure expertise is management. After all, neutron-science currently under way in the US, and Europe maintained and communities are not left pioneers built the original ILL in just over should soon follow suit. stranded. This constitutes a real challenge four years, though admittedly at a time of Despite last year’s reactor closures, for the remaining facilities. Sharing the less regulatory pressure. We must regain Europe is well prepared for the next decade It is also load via strategic collaboration is indis- that agility. The Chinese Spallation Neu- thanks to the continuous modernisation important pensable, and is the motivation behind tron Source has just reached its design of existing sources and investment in the to begin the recently created League of advanced goal of 100 kW, and the Spallation Neutron ESS. The value of neutron science will be European Neutron Sources (LENS). Source in Oak Ridge, Tennessee, is actively judged on its contribution to solving soci- strategic We must also ensure that the remain- pursuing plans for a second target station. ety’s problems, and I am convinced that discussions MINISTERIO ing facilities – which include the FRM II We therefore need to look to next- European researchers will rise to the chal- DE CIENCIA E INNOVACIÓN that aim in Munich, the Institut Laue-Langevin generation sources such as Compact lenge and carve a route to a greener future beyond 2030 (ILL) in France, ISIS in the UK and the Accelerator driven Neutron Sources through world-leading neutron science. @CDTIoficial

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BSBF.indd 1 24/04/2020 12:04 CCMayJun20_Viewpoint_v4.indd 49 24/04/2020 16:24 CERNCOURIER www. V o l u m e 6 0 N u m b e r 3 M a y /J u n e 2 0 2 0 CERNCOURIER.COM CERN authors can now publish open access with IOP Publishing at no cost OPINION Thanks to a new Publish and Read agreement between CERN and IOP Publishing, you can now: REVIEWS • Publish open access in more than 40 IOP Publishing journals at no cost to you • Increase your paper’s visibility and impact* •Expand Be compliant your with reach any open and access engagement requirement The benefits of choosing a digital-first publisher • Be covered whether your affiliation is primary or secondary •Publish Include articlesyour textbook, from CERN experimental monograph, collaborations review or handbook withsuch IOP as ATLAS, ebooks CMS, and LHCb benefit and ALICE from circulation to peers A unique exercise in scientific diplomacy at targeted institutions and conferences, as well as

Find out more at http://bit.ly/CERNIOP ITER timely marketing campaigns, member newsletters and ITER: The Giant Fusion much more. Rapid publication Multimedia Full-color print Reactor – Bringing a Sun We welcome proposals in all areas of physical sciences, times content copies to Earth applications, education, methods, computational tools By Michel Claessens and techniques. Springer

Choose the right publisher for you The International Thermonuclear Exper- If you are interested in being part of this rapidly expanding imental Reactor – now simply ITER – is book series, we’d like to hear from you. Submit a summary a unique exercise in scientific diplo- No Digital Rights e-reader A dedicated, macy, and a politically driven project. of your proposal to [email protected], and It is also the largest international col- * H Piwowar, J Priem, L V arivière, J P Alperin, L Matthias, B Norlander, A Farley, J West, S Haustein (2018) Management compatibility hands-on editor The state of OA: a large-scale analysis of the prevalence and impact of Open Access articles. includePeerJ 6:e4375 https://doi.org/10.7717/peerj.4375 a current biography and contact details. laboration, and a milestone in the tech- nological history of mankind. These, I would say, are the main conclusions of Michel Claessens’ new book ITER: The Giant Fusion Reactor – Bringing a Sun to Earth. He unfolds a fascinating story that criss-crosses more than 40 years of the history of nuclear fusion in a simple, but not simplistic, way that is accessible to anyone with a will to stick to facts with- g o e s t h r o u g h t h e d i ffic u l t i e s o f s e t t i n g up Opened up likely costing more than double what was out prejudices. The full range of opinions a complex project animated by a politi- ITER’s lid was initially planned – and as the author says CERN authors can now publish open access with o n I T E R’s c o nt r o v e r s i a l b e n e fit s a n d d et- cal agenda (fusion was on the agenda of removed on 2 April on more than one occasion, further delays riments are exposed and discussed in a political summits between the US and the - the Tokamak pit will likely entail additional costs. By fair way, and the author never hides his former USSR since the Cold War) without is nearly ready for comparison, the LHC needed roughly an IOP Publishing at no cost personal connection to the project as its a large laboratory backing it up. its first machine additional 25% in both budget and time head of communications for many years. Progress with ITER was made more component. compared to what was initially planned. Thanks to a new Publish and Read agreement between CERN and IOP Publishing, you can now: Why don’t we more resolutely pursue difficult by a complex system of in-kind a technology that could contribute to contributions that were not optimised for Price tag • Publish open access in more than 40 IOP Publishing journals at no cost to you the production of carbon-free energy? cost or technical success, but for political Was the initial cost estimate for ITER sim- • Increase your paper’s visibility and impact* ITER’s path has been plagued by rivalries “return” to each member state of ITER ply too low, perhaps to help the project get between strong personalities, and dif- (Europe, China, Japan, Russia, South approved, or would a better management, • Be compliant with any open access requirement ficult technical and political decisions, Korea, the US, and most recently India). with a different governance structure, Be covered whether your affiliation is primary or secondary though, in retrospect, few domains of sci- Claessens’ examples are striking, and he have performed better? Significantly, I • ence and technology have received such doesn’t skirt around the inevitable hot have not met a single knowledgeable per- • Include articles from CERN experimental collaborations strong and continuous support from gov- questions: what is the real cost of ITER? son who did not strongly express that ITER such as ATLAS, CMS, LHCb and ALICE ernments and agencies. Claessens’ book W i l l it e v e n b e fi n i s h e d g i v e n it s mu l t i pl e is a textbook case of bad management begins by discussing the need for fusion delays? How much of these extra costs organisation, though in my opinion, the among other energy sources – he avoids and delays are due to the complex and book does not do justice to the energetic selling fusion as the “unique and final” politically oriented governance struc- action of the current director-general, solution to energy problems – and quickly tures established by the partners? The Bernard Bigot. His directorate has been brings us to the heart of a key problem answers are clear, honestly reported, and a turning point in ITER’s construction, Find out more at http://bit.ly/CERNIOP that humanity is facing today. Travel- quantitative, though the author makes it and has set the project back on track in a ling through history, the author shows clear that the numbers should be taken moment of real crisis when many scien- that when politicians take decisions of cum grano salis. Assessing the cost of a tists and mangers expected the project to h i g h i n s pi r a t i o n, a s a t t h e f a m o u s fi r e s i d e project where 90% of the components are fail. A key question surfaces in the book: summit between presidents Reagan and in-kind contributions, with each partner is the price tag important? ITER’s cost * H Piwowar, J Priem, L V arivière, J P Alperin, L Matthias, B Norlander, A Farley, J West, S Haustein (2018) The state of OA: a large-scale analysis Gorbachev in Geneva in November 1985, having its own accounting structures, is peanuts compared to the European of the prevalence and impact of Open Access articles. PeerJ 6:e4375 https://doi.org/10.7717/peerj.4375 where the idea for a collaborative project and in certain cases no desire to reveal Union’s budget, for example, and the to develop fusion energy for peaceful pur- the real cost, is a doubtful enterprise. cost is not significant by comparison to poses was born, they change the course However, we can say with some certainty the promise that it delivers: carbon-free of history – for the better! The book then that ITER is taking twice as long and energy in large quantities, at an afforda-

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OPINION REVIEWS

ble cost to the environment, and based LHC a nd it s detec tors i n a n i ncompa r a- Michel of superconductor procurement at ITER Particle and o n a b u n d a nt a n d w i d e l y d i s t r i b ut e d f u e l. bly smaller volume. Comparisons with Claessens’ b e for e r e c e nt l y b e i n g i n s t a l l e d a s d e p ut y Though Claessens notes that there is CERN are a feature of the book, and a g r o up l e a d e r o f C E R N’s m a g n e t s d i v i s io n. book explores almost no intrinsic innovation in ITER, p oi nt o f pr i d e for h i g h- e n e r g y p h y s i c i s t s I recommend Michel Claessens’ well h e s h o w s h o w t h e pr oj e c t h a s n e v e r t h e- – clearly, CERN has set the standard for different w r it t e n a n d e a s y-t o -r e a d b o o k . It i s p a s- nuclear physics l e s s p u s h e d t o k a m a k t e c h n ol o g y b e y o n d high-tech international collaboration, points of sionate and informative, and explores dif- its apparent limits by a sheer increase in and ITER has tried to follow its example view without fe r e nt p oi nt s o f v ie w w it h o ut f a n a t ic i s m. size, though he neglects some key points, (CERN Courier October 2014 p45). Having fanaticism Interestingly, his conclusion is not scien- such as the incredible stored energy of begun my career as a plasma scientist, t i fic or p ol it i c a l, b ut s o c i o -p h i l o s o p h i c a l the superconducting magnets. An inci- I have seen the connections between in nature: ITER will be built because it Find the information you need from IOP Publishing’s world-leading dent similar to that suffered by the LHC the laboratories first-hand: they range can be, he says, according to a principle in 2008 would be a logistical nightmare from Robert Aymar, a former CERN of “technological necessity”. journals and award-winning books programme, along with conference for ITER, as it contains more than three d i r e c t or-g e n e r a l a n d a r e c o g n i s e d f a t h e r proceedings and science news from Physics World. times the stored energy of the entire of ITER, to Arnaud Devred, who was head Lucio Rossi CERN. Obsessed by a Dream: gained in several countries to hitherto A f t e r W i d e r ø e’s r e t u r n t o O s l o i n M a r c h The Physicist Rolf Widerøe r e s t r i c t e d a r c h i v e s h a s pr o v i d e d a w e a l t h 1945, when the betatron was operational Publish with us of new material and insights, in particu- and the advancing English army made – a Giant in the History of lar in relation to the Second World War. a study of a 200 MeV betatron illusion- We offer a range of publishing options to suit your needs, ensuring that Accelerators Sørheim’s book focuses not on physics ary, he faced official prosecution on the or technology, but on Widerøe himself, ludicrous main charge of having helped your work gets the attention that it deserves. By Aashild Sørheim a n d t h e s o c i a l a n d p ol it ic a l e n v i r o n m e nt develop V2 rockets, explains Sørheim. Springer in which he had to find his way. In par- Released from prison after 47 days, he iopscience.org/particle-and-nuclear-physics ticular, it gravitates to the question of his got away without trial, but had to pay The betatron is an early type of motivation to work in Germany in the a substantial fine. Unemployed, seeing MeV-range electron accelerator that troubled years from 1943 to 1945, when no basis for pursuing his dream of fur- uses the electric field induced by a var- he constructed a betatron, the accelerator ther developing betatrons in his home ying magnetic field to accelerate elec- that he had invented two decades earlier c o u nt r y, a n d w it h t h e s t i g m a o f a c ol l a b - trons, or beta particles. It operates like a while a st udent in Karlsr uhe. or a t or i n t h e u n d e r s t a n d a bl y o v e r h e a t e d t r a n s for m e r w it h t h e s e c o n d a r y w i n d i n g atmosphere of the time, he moved his replaced by a beam of electrons circu- Occupied Oslo f a m i l y t o S w it z e rl a n d i n 1946. O n e c h a p - l a t i n g i n a v a c uu m t u b e. It w a s i n v e nt e d In the most interesting parts, the book ter, strangely put near the beginning of by pioneering Norwegian accelerator provides background information about the book, describes how Widerøe then physicist Rolf Widerøe when a student the entanglement of science, industrial became a successful leader of the beta- in 1925. Since the construction failed at i nt e r e s t s a n d a r m a m e nt, a n d i n p a r t i c u- tron construction at Brown-Boveri in t h e t i m e, h e h a d t o fi n d a n o t h e r t h e m e for lar the possible reasons for the “recruit- Switzerland, a respected lecturer at the his thesis, and so in 1927 he constructed ment” of Rolf Widerøe in occupied Oslo ETH in Zurich and a promoter of radi- t h e fi r s t l i n e a r a c c e l e r a t or (50 keV), before in the spring of 1943 by three German ation therapy until late into his retire- later proposing the principle of colliding physicists mandated by the German Air ment. He was a CERN consultant in the beams to fully exploit the energy of accel- For c e, w h o i n s i nu a t e d t h a t w i l l i n g n e s s t o early days, and worked with Odd Dahl e r a t e d p a r t ic l e s. T h r o u g h t h e s e i n n o v a- c o o p e r a t e m i g ht w e l l h e l p t o i m pr o v e t h e a n d F r a n k G o w a r d i n Br o o k h a v e n i n 1952 tions, Rolf Widerøe decisively influenced c o n d it i o n s o f h i s br o t h e r V i g g o, w h o w a s w h e r e t h e y b e c a m e a c q u a i nt e d w it h t h e the course of high-energy physics, with i n pr i s o n i n G e r m a n y for h e l pi n g Nor w e- alternating-gradient focusing princi- betatrons shaping the landscape in the gians escape to England. The apparent ple that was then boldly proposed to the early days, and linear accelerators and motivation was that a powerful betatron CERN Council as basis for the design of colliding beams becoming indispensable could produce strong enough X-rays to t he 25 GeV Proton Synchrotron. tools today. n e ut r a l i s e a l l i e d b o m b e r pi l o t s. A l t h o u g h The book leaves the reader somehow Aashild Sørheim, a professional writer, leading German scientists quickly dis- o v e r w h e l m e d b y t h e a m o u nt o f m a t e r i a l now presents a new biography of this c o v e r e d t h i s t o b e n o n s e n s e, t h e b e t a t r o n pr e s e nt e d, t h e n o n- c h r o n ol o g i c a l pr e s- visionary engineer, who had a semi- project was not interrupted. entation, and the many repetitions of nal impact on accelerator physics. Her The book describes the difficult the same facts, conveying the impres- book covers Widerøe’s whole life, from working conditions in Hamburg, and sion that the author had difficulty in 1902 to 1996, and from his childhood in t he prog re s s tow a rd s a 15 MeV betatron. putting the information in a coherent a well-to-do family in Oslo, to his retire- Among the key players was Widerøe’s ord e r. Ho w e v e r, t h e m a n y i nt e r v i e w s a n d m e nt i n S w it z e rl a n d. C e r t a i n l y, m a n y w h o assistant Bruno Touschek, who was new documentary evidence, including a r e a d P e d r o Wa l o s c h e c k’s 1994 bio g r a p h y, finally arrested by the Gestapo in 1945 hitherto unknown letter from his brother The Infancy of Particle Accelerators: Life and Widerøe as his mother was Jewish. It was during Viggo, open novel perspectives on this Work of Rolf Widerøe, will be curious as to faced official this time that Widerøe patented his idea extraordinary engineer and scientist how this new book will complement the prosecution on to use colliding beams to ma x imise t he who, besides receiving many honours for mer. S ørhe i m’s ne w offer i ng i s ba se d the ludicrous energy available, against the advice of a br o a d, fi n a l l y a l s o r e c e i v e d r e c o g n it ion o n n e w d o c u m e nt a r y e v id e n c e, t h e r e s u lt charge of Touschek, who found the idea too trivial in his home country, after a lengthy rec- o f p a i n s t a k i n g s i f t i n g t h r o u g h a r c h i v e s, to publish. It was the Touschek though, onciliation process. and a large number of interviews. She having helped who in 1961 first used this principle in has opened new perspectives through develop V2 ADA, the e+e– ring in Frascati, which was Kurt Hübner formerly of CERN her interviews, and the access she has rockets the first collider ever built. (now retired).

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Opening doors with a particle-physics PhD L Esteveny/CERN L Transferable skills in communication, teamwork and computing make particle-physics PhDs highly sought after by industry.

Alexandra Martín Sánchez began her studies in particle physics at the University of Sala- manca, Spain, in 2003, during which she had an internship at the University of Paris-Sud at Orsay working in the LHCb collaboration. This prompted her to take a master’s degree in parti- cle physics, followed by a PhD at Laboratoire de l’Accélérateur Linéaire (LAL) in Orsay. She worked on CP violation in B0 → DK*0 decays and hadronic trigger performance with the LHCb detector, and the subject fascinated her. She recalls with emotion witnessing the announcement of the Higgs-boson discovery in July 2012 from Mel- bourne, Australia, where the ICHEP conference was being held and where she was presenting her work: “Despite the distance, the atmosphere Transition Former LHCb user Alexandra Martín Sánchez, now a project manager in scientific was super-charged with excitement.” computing at energy firm EDF, standing in front of her old office at CERN. Yet, one year later, Alexandra decided to leave the field. Why? “There were possibilities to do a at ease in all aspects of the job, whether it was tected by such structures. On the other hand, postdoc in Marseille for LHCb, or elsewhere for coding, functioning in teams or collaborating they have a cumbersome administrative side, other experiments, but I had already changed with other services.” which means that things do not necessarily countries once and had created strong links move as quickly as we would like. What I miss, in Paris,” she explains. “I loved working in Moving on however, is the international aspect of the col- Your Dry Vacuum Solutions research at CERN, and if it had been easier to After one year with the firm, Alexandra was laborations. Today I’m thinking of staying at EDF continue in this way I would have, but getting a recruited by EDF R&D, just as she had hoped for. because I’m happy there. The career paths are permanent position is particularly hard nowa- I n it i a l l y j oi n i n g a s a r e s e a r c h e n g i n e e r, fi v e y e a r s varied and the company motivates its engineers Partner for Particle Accelerators days and you need to do several postdocs, often later she is now project manager of open-source to change jobs every four or five years, unless switching countries.” software called SALOME and leads a team of they wish to become specialists in their fields.” After submitting her thesis, she consulted the seven people. SALOME is used for industrial The biggest lesson is that the skills she had TwisTorr 305-IC and TwisTorr 305 FS Clean, quiet, performing, easy to integrate careers office at Orsay to discuss her options. studies that need physical simulations, making learned during the process of obtaining a PhD in and connected vacuum for your experiments But it was word-of-mouth and friends who it possible to model EDF’s operation of facilities an environment like CERN are extremely trans- had already made the transition from research and means of production, such as nuclear power ferable. “During my recruitment interviews, I to industry that were the biggest help. After plants or hydroelectric dams. “Computer sci- highlighted my programming experience, my – New TwisTorr 305 turbo pumps with smart connectivity: Bluetooth, USB and NFC attending an IT careers fair in Paris in 2013, ence is the same as at CERN, even if it is applied ability to communicate and present my work, she was offered a job with French firm Ber- to different data. Programming is also done in and especially my ability to complete a thesis tin Technologies, who were looking for skills Python and C++. The code used is also that gen- project over several years,” she says. “My advice – IDP dry scroll pumps: sustainable, quiet, oil-free, with inlet isolation valve in scientific computing, in particular to offer erated by researchers, that is to say, more or less to alumni looking for a job is to make the most consulting services for large groups including ‘industrial’ and I easily found my way around, as of this PhD experience. Both sides of the job IDP-7 and IDP-10 Scroll Pumps – Wide portfolio of ion pumps and controllers, from the inventor of UHV French energy giant EDF. Reckoning that this we share the same development work habits. At are of interest to recruiters: the technical part first step into industry could open the door to a CERN we work on software developed by CERN, but also the communication and collaboration large company, she took the plunge. and at EDF on software developed by EDF. In skills with researchers and engineers from all Learn more: “Bertin Technologies had recruited me both cases it is also teamwork. The principles over the world. This makes a real difference from without having a clear idea regarding the pro- remain the same,” she explains. candidates coming from an engineering school: www.agilent.com/chem/vacuum file of a particle-physics researcher, but they “Large groups like EDF are of course fairly the thesis is a real professional experience!” 00 800 234 234 00 (toll-free) • [email protected] w e r e i m m e d i a t e l y v e r y s a t i s fie d w it h t h e w a yI hierarchical companies, but CERN is also very worked. My recruiters were surprised to see me large and very hierarchical. One can feel pro- Interview by Laure Esteveny CERN.

© Agilent Technologies, Inc. 2020 Agilent Ion Pump and IPCMini controller

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TECHNOLOGY Appointments and awards e tone Ber V FOR BIG SCIENCE Rossi receives Wideröe Prize National Order of the Lion carry out research into the Lucio Rossi of CERN, who Fama Diagne Sène, first director interplay between Earth’s is project leader for the of the library at Alioune Diop magnetic field and the solar KOREAN EXCELLENCE High-Luminosity LHC, is University of Bambey, Senegal, wind, while also producing FOR YOUR I&C SOLUTIONS the recipient of the European was included in the country’s virtual-reality experiences and a Physical Society Accelerator National Order of the Lion with “magnetospheric drum kit” to Group IPAC’20 Rolf Wideröe the grade of knight at a ceremony be used in creating works Prize for outstanding work in held in Dakar on 24 February, for performance. the accelerator field. Rossi was for her services to the nation. Francesca Chadha-Day recognised “for his pioneering Diagne Sène has a long (King’s College London) will role in the development of relationship with CERN. She use astronomical observations superconducting magnet participated in the CERN– to search for axion-like technology for accelerators and UNESCO School on Digital particles, and will communicate WE DEVELOP TODAY THE TOOLS experiments, its application to Libraries in 2011, was a visiting her research through FOR THE FUTURE OF PARTICLE complex projects in high-energy librarian in CERN’s scientific stand-up comedy. physics including strongly driving information service for six Andrei Constantin (University ACCELERATORS industrial capability, and for his months in 2015, and is a member of Oxford) will conduct

tireless effort in promoting the collaboration in 2014 to honour S Bennett/CERN mathematical research to help Bespoke Electronics for Particle Accelerators: field of accelerator science and the legacy of Wu-Ki Tung, one of map string theory to elementary • BPM and LLRF controllers technology”. The award was due the leading researchers on QCD particles, linked with a range

• Motion control, HV and vacuum controllers CERN and the founder of CTEQ. of outreach activities including talks to local schools. Software and Hardware Solutions for Integrated Control: ATLAS 2019 thesis awards Ömer Gürdoğan (University • Distributed control systems & SCADA: EPICS, WinCC, Selected from a total of 35 of Southampton) will focus LabView nominations, the six winners of on scattering amplitudes in • PLC engineering: Siemens, Beckhoff, TwinCAT the ATLAS 2019 thesis awards quantum field theory and • FPGA solutions were announced on 27 February. conduct outreach activities Pictured, from left to right, including art exhibitions. Interlocks and Safety Systems: Many more tailored products are: Ahmed Tarek Abouelfadl Scott Melville (University for accelerators and fusion machines: Mohamed (Paris-Diderot of Cambridge) will work on • Mission-critical systems for fusion reactors and University); Stephen Burns effective field theories and their accelerators • ITER Central Interlock System Menary (University of application to problems in • Safety international standards expertise: IEC 61511, IEC • High Voltage Controllers Manchester); Daniel Joseph gravity and cosmology, and give 61508 • LLRF Controller for RAON Accelerator Antrim (University of California, public talks. • Undulator Controller for PAL X-FEL Irvine); Khilesh Pradip of the scientific committee Francesco Muia (University Machine Learning Solutions for Operations: (University of Pennsylvania); organising the biannual CERN– of Cambridge) will explore the • Reinforcement learning for accelerator control systems and Elodie Deborah Resseguie UNIGE Workshop on Innovations catastrophic processes that with MOI AI platform. to be presented on 14 May during (University of Pennsylvania). in Scholarly Communication. produced gravitational waves Not pictured: Karri Folan Di • Deep neural network applications for beam prediction and this year’s International Particle during the early universe, Accelerator Conference (IPAC’20), Petrillo (Harvard University). First Stephen Hawking and aim to inspire others via optimization which has been cancelled due to The ATLAS collaboration has Fellows announced public-engagement activities on the situation with coronavirus. almost 1200 PhD students, and In recognition of Stephen the history of the universe. theses awarded can cover any Hawking’s contributions to Rebecca Nealon (University Wu-Ki Tung Award for area of ATLAS physics, including science and its popularisation, of Warwick) will focus on the Early Career Research detector development, operations, UK Research and Innovation formation of protoplanetary Theorist Valerio Bertone of CEA software and performance (UKRI) has announced the first discs, and use numerical Paris-Saclay, has been granted studies, and physics analysis. nine Stephen Hawking Fellows. simulations in public talks and

the 2019 Wu-Ki Tung Award for K Anthony/ATLAS Each fellowship provides up outreach activities. Early Career Research on QCD, to four years’ funding and Stefan Schacht (University of “for innovative contributions supports fellows with training in Manchester) aims to build on the to the precise determination public engagement. recent observation by LHCb of CP of parton distributions and Danai Antonopoulou violation in the charm system to LLRF Controller for PAL X-FEL EPICS ported Step-Motor Controller BPM Controller for RAON Accelerator Vacuum Controller fragmentation functions, and for (University of Manchester), explore the matter–antimatter • Excellent stability perfor-mance • Fast and stable control of up to Accelerator • Integrated and compact (1U) control the development of cutting-edge will research the properties, asymmetry, and plans to of 0.02% (amplitude) eight motors • 16 RF inputs and 4 BPM processors of beamline vacuum instrumentation and 0.03o (phase) • Compact design with Ethernet per controller • Up to 20 valves, 8 motors and gauge software to perform global PDF such as superfluidity and establish an outreach programme • Independent channel amplifier communication • Position and phase resolution control (RS232) fits”. The $5000 award, given superconductivity, of neutron for particle physics at the annual control • Embedded EPICS IOC, Channel better than 5 μm and 0.1º • Control of up to 64 motors (RS485) annually to a young physicist stars and plans to undertake a Bluedot Festival. • Embedded EPICS IOC and Channel Access • Embedded EPICS IOC and Channel • Embedded EPICS IOC, Channel performing either experimental detailed public-engagement UKRI will support up to 50 Access Access Access or theoretical research on QCD, programme targeted at postdoctoral scientists through was established by the CTEQ underrepresented groups. the Stephen Hawking Fellowships (Collaborative Theoretical and Martin Archer (Imperial scheme, with further calls to be Experimental studies of QCD) College London) will launched in due course. mobiis.com/en [email protected] CERN COURIER MAY/JUNE 2020 57

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For advertising enquiries, contact CERN Courier recruitment/classified, IOP Publishing, Temple Circus, Temple Way, Bristol BS1 6HG, UK. Te l +4 4 (0)1 17 930 1 264 E-m a i l s a le s@c e r nc ou r ie r.c om. At MYRRHA, we firmly believe that our unique research facility must serve society. Please contact us for information about rates, colour options, publication dates and deadlines. That’s why we’re building an Accelerator Driven System (ADS): our sub-critical lead-bismuth cooled reactor will be driven by a super conducting, high power proton linear accelerator.

Set out to change the world. Our goal CERN seeks to hire an experimental physicist Join us at the forefront of innovation. We are looking for your Our initial goal is to build the first 100 MeV stage of the expertise in many accelerator technology fields, especially superconducting, high power proton linac. This includes (indefinite appointment) in RF, LLRF, high power applications and controls. Do you feel selecting systems and components with redundancy and for a challenge that contributes to solving some of society’s extreme reliability in mind, as we are compiling the first large CERN’s Experimental Physics Department carries out research in the field of most important issues, such as closing the nuclear fuel cycle, scale application of solid state RF amplifiers for high power experimental particle physics, aiming to provide a stimulating scientific atmosphere transforming the lives of cancer patients or conducting accelerators. and remains an important reference centre for the European physics community. fundamental physics research? Don’t look any further and apply. It contributes to the education and training of young scientists. The Experimental Physics Department invites applicants for the indefinite We are ready to design and build this accelerator. Are you? appointment of a Physicist in experimental particle physics research. Join a community of young and energetic explorers For more information and details of how to apply, see http://cern.ch/go/9svd

Deadline 2 June 2020 12pm CEST Imagine working in a place like nowhere else on earth. Take part. Home.cern.

ELI Beamlines research centre in Dolní Břežany is part of pan-European We o er: “Building the most reliable Extreme Light Infrastructure supporting scienti c excellence in Europe • the opportunity to participate in this unique scienti c project accelerator in the world is a by making available its capacities to the best scienti c teams across • competitive and motivating salary the world. The ELI Beamlines is part of the Institute of Physics of the •  exible working hours challenge that appeals to me.” Czech Academy of Sciences. The High Field Initiative project at the • career growth Angélique Gatéra ELI-BL is established to be the leading project in the high  eld science. • lunch vouchers, pension contribution and 5 sick days • support of leisure time activities Interviews will begin immediately and the position will stay open No spontaneous chain reaction Nuclear waste treatment Linac and nuclear medicine The HiFI-ERT (Excellence Research Team) recruits until  lled. Accelerator Driven Systems stand or Lead-bismuth eutectic cooled ADS systems The MYRRHA linac will enable a scientist for developing theory and computer fall by their accelerator: no neutron are ideally suited to convert the highest research and production of current simulations on the following activities: Applications, containing CV, cover letter, contacts of references, and any other material the candidate considers relevant, should be sent production means no fission reaction. radiotoxic nuclear waste into new elements and novel radioisotopes, for • theory of charged particle acceleration and hard electromagnetic to Mrs. Jana Ženíšková, HR specialist ([email protected], with more easily manageable storage needs. instance for cancer diagnostics and radiation in relativistic laser plasma +420 - 601560322). MYRRHA is the prototype link towards treatment. • development and use of various computer codes for simulation of Information regarding the personal data processing and access to sustainable industrial solutions. nonlinear processes in laser plasmas the personal data at the IoP CAS can be found on: Further questions on scienti c project can be addressed to https://www.fzu.cz/en/processing-of-personal-data. Sergei Bulanov ([email protected]) https://www.sckcen.be/en/careers Requirements: • PhD in Physics or Mathematics with the focus on theoretical and computation physics related to nonlinear waves, charged particle acceleration, quantum electrodynamics, numerical modeling of relativistic plasmas

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Deutsches Elektronen-Synchrotron DESY Deutsches Elektronen-Synchrotron DESY A Research Centre of the Helmholtz Association A Research Centre of the Helmholtz Association

For our location in Zeuthen we are seeking: Karlsruhe Institute of Technology (KIT) – The Research University in the Karlsruhe Institute of Technology (KIT) – The Research For our location in Hamburg we are seeking: Helmholtz Association creates and imparts knowledge for the society Postdocs for Photo Injector Test Facility University in the Helmholtz Association – creates and imparts and the environment. It is our goal to make significant contributions to Karlsruhe Institute of Technology (KIT) – The Research University in the knowledge for the society and the environment. It is our PITZ in Zeuthen Scientist for the Low Level RF Controls mastering the global challenges of humankind in the fields of energy, Helmholtz Association creates and imparts knowledge for the society goal to make significant contributions to mastering the mobility, and information. For this, about 9,300 employees of KIT cooperate of the European XFEL (LLRF) andKarlsruhe the environment. Institute of TechnologyIt is our goal (KIT) to make – The significant Research University contributions in the to global challenges of humankind in the fields of energy, DESY Helmholtzin a broad Association range of disciplines creates and in research,imparts knowledge academic education, for the society and mastering the global challenges of humankind in the fields of energy, mobility, and information. For this, about 9,300 employees DESY is one of the world’s leading research centres for photon science, particle mobility,andinnovation. the environment. and information. It is For our this, goal about to make 9,300 significantemployees ofcontributions KIT cooperate to DESY of KIT cooperate in a broad range of disciplines in research, and astroparticle physics as well as accelerator physics. More than 2400 inmastering a broad the range global of challenges disciplines of in humankind research, academic in the fields education, of energy, and academic education, and innovation. employees work at our two locations Hamburg and Zeuthen in science, technology DESY is one of the world’s leading research centres for photon science, innovation.mobility,In KIT Division and information. V – Physics Forand this, Mathematics about 9,300 – atemployees the Institute of KIT for cooperate Beam and administration. particle and astroparticle physics as well as accelerator physics. More inPhysics a broad and Technology range of disciplines (IBPT) and in at research, the KIT Department academic education, of Physics and The KIT Department of Physics, part of Division V – Physics The Photo Injector Test Facility PITZ in Zeuthen (near Berlin) develops high than 2400 employees work at our two locations Hamburg and Zeuthen in Ininnovation.a new KIT Division V – Physics and Mathematics – at the Institute for Beam and Mathematics – invites applications for a brightness electron sources for Free-Electron Lasers (FELs) like FLASH and science, technology and administration. Physics and Technology (IBPT) and at the KIT Department of Physics European XFEL. The research program at PITZ concentrates on optimization of the aIn new KIT Division V – ProfessorshipPhysics and Mathematics (W3) – at the Institute for Beam electron beam quality for pulsed photo injectors and developments towards future The group MSK is responsible for the controls, feedback regulations Physics and Technology (IBPT) and at the KIT Department of Physics Professorship (W3) in CW electron sources, as well as on applications of high brightness electron beams. and synchronization of the particle accelerators at DESY. We are an a newfor Laser-basedProfessorship Particle (W3)Accelerators international team of technicians, engineers and scientists who develop, Experimental Particle Physics The position for Laser-basedProfessorship Particle (W3) Accelerators install and operate complex instruments for the European X-Ray Free- is to be filled at the earliest date possible. The professorship is associated 3 Postdoc positions are available at PITZ for the following tasks (More details can at the Institute of Experimental Particle Physics (ETP). Electron Laser. withfor leading Laser-based a department of IBPT. Particle The recruitment Accelerators takes place in the be found under https://pitz.desy.de/jobs ): is to be filled at the earliest date possible. The professorship is associated We are looking for an outstanding scientist with a research suspension model in accordance with Art. 15 § 2 KIT Act (“Beurlaubungs- l with leading a department of IBPT. The recruitment takes place in the Participate in the upgrade of the photocathode laser systems and develop focus on experimental particle physics, in particular in the The position ismodell to be gemäß filled §at 15 the Abs. earliest 2 KIT-Gesetz”). date possible. The professorship is associated innovative concepts and techniques for the diagnostics of high-quality laser and suspension model in accordance with Art. 15 § 2 KIT Act (“Beurlaubungs- areas of precision measurements and searches for physics l with leading a department of IBPT. The recruitment takes place in the Further development of high precision field control of the modell gemäß § 15 Abs. 2 KIT-Gesetz”). beyond the Standard Model, and on algorithm development electron beams. Perform numerical simulations to support the accelerator R&D suspensionWe are looking model for inan accordance experienced with scientist Art. to15 advance§ 2 KIT Actand (“Beurlaubungs- represent the program at PITZ towards applications of high brightness electron beams: superconducting cavities at the European XFEL and detector technologies. The successful candidate is Wemodellresearch are gemäßlooking area of § compactfor 15 anAbs. experienced accelerator2 KIT-Gesetz”). technologiesscientist to advance at KIT. A and focus represent will be la- the job offer APPO005/2020 l Coordination of LLRF systems operation with the XFEL machine expected to strengthen and expand the KIT activities at research area of compact accelerator technologies at KIT. A focus will be la- l ser-based technologies, investigations of the underpinning beam dynamics Further developments of tools for detailed characterization of the electron beam the Belle II experiment. We welcome your participation in operation group ser-basedWeoptimization are looking technologies, of for the an corresponding experienced investigations scientist laser of the systems tounderpinning advance and system and beam represent reliability dynamics the phase space. Perform accurate modeling and numerical simulations of electron l Quality control towards optimal operation of the LLRF system and optimizationresearch area of of compact the corresponding accelerator technologies laser systems at and KIT. systemA focus will reliability be la- the preparation of future collider experiments. beam measurements using scintillating screens. Develop, test and support of novel compact facilities in experiment and simulation. The appointed investigations of RF trips ofser-based novel compact technologies, facilities investigations in experiment of the and underpinning simulation. beamThe appointed dynamics software packages for automatization and optimization of electron beam professor is expected to develop the scientific profile of the IBPT’s KIT provides an excellent environment for research in l Operation anlysis and further development of the field regulation and professoroptimization“Accelerator is R&D expected of theand correspondingOperation to develop I” department the laser scientific systems and to and profileparticipate system of reliability in thethe IBPT’s particle and astroparticle physics. ETP has long-term measurements: job offer APPO006/2020 “Acceleratorof novel compact R&D andfacilities Operation in experiment I” department and simulation. and to participate The appointed in the l Helmholtz Association of German Research Centres’ programme-oriented involvements in the large-scale projects CMS and Belle II. Perform numerical simulations and experimental studies of semiconductor automation algorithms Helmholtzprofessor isAssociation expected of to German develop Research the scientific Centres’ programme-oriented profile of the IBPT’s l funding, in particular in the programme “Matter and Technologies”. In The infrastructure at ETP includes a semiconductor photocathode (Cs2Te, CsK2Sb) photoemission in high gradient RF guns, Documentation and maintenance of the LLRF systems funding,“Accelerator in particular R&D and inOperation the programme I” department “Matter and and to Technologies”.participate in the In addition to new accelerator technologies, research topics and tasks in the laboratory, workshops and computer clusters. Close ties including particle dynamics in the material and in vacuum during the emission additionHelmholtz to Association new accelerator of German technologies, Research research Centres’ topics programme-oriented and tasks in the programme include methods of beam control and diagnosis as well as the exist with the Tier-1 computing centre GridKa. Research process. The goal is to better understand and improve the photocathodes and Requirements programmefunding, in particularinclude methods in the ofprogramme beam control “Matter and diagnosis and Technologies”. as well as the In design and operation of the institute’s accelerator test facilities. at ETP is mainly funded by the BMBF, the DFG and the the photoemission dynamics to minimize the cathode emittance: job offer l PhD degree in Physics, Electronics or Computer Science or equivalent designaddition and to operationnew accelerator of the technologies,institute’s accelerator research test topics facilities. and tasks in the APPO007/2020 Helmholtz Association. qualification programme include methods of beam control and diagnosis as well as the KITdesign offers and an operation outstandingoutstanding of the interdisciplinary interdisciplinary institute’s accelerator environment environment test facilities.at atthe the interface interface l ETP is part of the KIT Centre Elementary Particle and Requirements Several years experience in RF control of superconducting particle of the engineering and natural sciences. The incumbent will cooperate of the engineering and natural sciences. The incumbent will cooperate Astroparticle Physics (KCETA) and is involved in further Please find more details in the specific announcements mentioned above. accelerators closelyKIT offers with an colleaguescolleagues outstanding ofof theinterdisciplinarythe Accelerator Accelerator Technology Technologyenvironment Platform Platform at the (ATP) interface(ATP) at at l large-scale projects such as the Pierre Auger Observatory, Excellent university degree in accelerator physics or semiconductor surface l KIT.of the He/she engineering raises third-party third-party and natural funds funds from sciences. from national national The and incumbent and international international will cooperatesources sources Advanced understanding of the system architecture and operation of IceCube, KATRIN and XENON. Close collaborations exist physics with PhD andclosely actively with colleagues supports supports the the of transfer transferthe Accelerator of of scientific/technical scientific/technical Technology Platform results results (ATP)into into ap- at ap- l particle accelerators with strong theory groups working on particle and Strong background in beam dynamics simulations of space charge dominated plications.KIT. He/she Inraises In academic academic third-party education, education, funds from candidates candidates national are areand expected expectedinternational to to actively activelysources l Skills in automation and system control astroparticle phenomenology. The Karlsruhe School of beams; familiar with numerical simulations (e.g. ASTRA, GEANT) and high level participateand actively inin supports existingexisting and theand newly transfernewly established established of scientific/technical German German and and English resultsEnglish study intostudy ap- l Computer science skills in Linux, Python, Firmware and Software Elementary Particle and Astroparticle Physics: Science and scripting languages (like Python, Matlab); good programming skills programsplications. offered In academic byby the the KIT education,KIT Department Department candidates of of Physics. Physics. are expected to actively l Knowledge/skills in experimental characterization of photocathodes and l Strong motivation and pragmatism towards problem solving as well as participate in existing and newly established German and English study Technology (KSETA) provides access to an excellent pool photoemission or of particle beams using image processing programs offered by the KIT Department of Physics. of Ph.D. students. highly proficient English skills The candidate has has an an outstanding outstanding scientific scientific record record in in the the field field of of l Very deep knowledge of accelerator physics and accelerator technology or very laser-based particle acceleration, excellent teaching skills and leader- laser-based particle acceleration, excellent teaching skills and leader- The appointed professor will be part of the ETP board good knowledge in laser technology For further information please contact Julien Branlard shipThe experience.candidate has Further an outstanding prerequisites scientific are experience record in thein operationthe field of l ship experience. Further prerequisites are experience in the operation of directors and assume responsibilities in the academic Very good knowledge of English is required and knowledge of German is oflaser-based large-scale particle facilities, acceleration, in application-oriented excellent teaching research skills and leader-in the +49-40-8998-1599. of large-scale facilities, in application-oriented research and in the self-administration. The candidate is required to teach at of advantage acquisitionship experience. of third-party Further prerequisites funds. Experience are experience in technology in the transfer operation is l acquisition of third-party funds. Experience in technology transfer is all levels of the undergraduate and graduate curriculum Participate in the operation of PITZ for accelerator R&D The position is limited to 3 years. desirable.of large-scale facilities, in application-oriented research and in the desirable. (eventually in German) and to supervise bachelor, master Please mark in your application for which of the 3 positions you are applying. Salary and benefits are commensurate with those of public service acquisition of third-party funds. Experience in technology transfer is organisations in Germany. Classification is based upon qualifications and KITdesirable. aims to increase diversity at the academic management level and in and Ph.D. students. A Habilitation degree or equivalent For further information please contact Dr. Frank Stephan, +49-33762 77-338, particularKIT aims to the increase proportion diversity of at female the academic professors management and therefore level welcomesand in scientific and teaching qualifications are required. [email protected]. assigned duties. Handicapped persons will be given preference to other KITparticular aims to the increase proportion diversity of female at the professorsacademic andmanagement therefore welcomeslevel and in applications from women. KIT promotes the compatibility of family and KIT is pursuing the strategic goal of substantially increasing equally qualified applicants. DESY operates flexible work schemes. DESY careerparticularapplications and the offersfrom proportion women. support KIT of within femalepromotes the professors scope the compatibility of its and Dual therefore Careerof family welcomes Program. and The positions are initially limited to 2 years. gender balance and diversity of its faculty. As an equal applications from women. KIT promotes the compatibility of family and Salary and benefits are commensurate with those of public service organisations is an equal opportunity, affirmative action employer and encourages Applicantscareer and offerswith a support disability within having the scope the same of its Dualqualification Career Program. are given career and offers support within the scope of its Dual Career Program. opportunity employer, KIT explicitly encourages in Germany. Classification is based upon qualifications and assigned duties. applications from women. Vacant positions at DESY are in general open preferentialApplicants with consideration. a disability According having the to same § 47 qualification Landeshochschulgesetz are given Applicants with a disability having the same qualification are given applications from women as well as from all others who Handicapped persons will be given preference to other equally qualified applicants. to part-timework. During each application procedure DESY will assess (LHG)preferential of the State consideration. of Baden-Württemberg, According to §a completed 47 Landeshochschulgesetz university degree, preferential consideration. According to § 47 Landeshochschulgesetz will bring additional diversity to the university’s research DESY operates flexible work schemes. DESY is an equal opportunity, affirmative pedagogical(LHG) of the Stateaptitude, of Baden-Württemberg, which as a rule must a completed be demonstrated university bydegree, experi- whether the post can be filled with part-time employees. ence(LHG) inof teachingthe State orof training,Baden-Württemberg, and a special a completed aptitude for university scientific degree, work, and teaching. KIT provides support for dual career couples action employer and encourages applications from women. Vacant positions at pedagogical aptitude, which as a rule must be demonstrated by experi- pedagogical aptitude, which as a rule must be demonstrated by experi- and families. Applicants with disabilities will be preferentially We are looking forward to your application via our application system: whichence in as teachinga rule is demonstrated or training, and by athe special quality aptitude of a doctorate, for scientific are required. work, DESY are in general open to part-timework. During each application procedure ence in teaching or training, and a special aptitude for scientific work, considered if suitably qualified. The terms of employment DESY will assess whether the post can be filled with part-time employees. which as a rule is demonstrated by the quality of a doctorate, are required. www.desy.de/onlineapplication Kindlywhich as send a rule your is demonstrated application including by the quality the usualof a doctorate, documents are (i.e., required. a CV, are listed in § 47 Landeshochschulgesetz (LHG) of the State We are looking forward to your application via our application system: research plan, statements of previous and anticipated teaching activities of Baden-Württemberg. Deutsches Elektronen-Synchrotron DESY Kindly send your application including the usual documents (i.e., a CV, www.desy.de/onlineapplication andKindly a list send of yourpublications) application before including May 11 theth, 2020 usual (preferably documents in (i.e.,electronic a CV, Human Resources Department | Code: MMA020/2020 research plan, statements of previous and anticipated teaching activities Qualified candidates should submit before 15.06.2020 a formresearch as aplan, single statements pdf document) of previous to: Dekanat and anticipated der KIT-Fakultät teaching für activities Physik, Deutsches Elektronen-Synchrotron DESY th Notkestraße 85 | 22607 Hamburg Germany and a list of publications) before May 11 ,th 2020 (preferably in electronic curriculum vitae, list of publications, as well as research Human Resources Department | Karlsruherand a list of Institut publications) für Technologie before May (KIT), 11 76128, 2020 Karlsruhe, (preferably Germany, in electronic email: form as a single pdf document) to: Dekanat der KIT-Fakultät für Physik, and teaching statements to: Dekanat der KIT-Fakultät für Code: APPO005/2020 - APPO006/2020 - APPO007/2020 Phone: +49 40 8998-3392 [email protected] as a single pdf document) to: Dekanat der KIT-Fakultät für Physik, Karlsruher Institut für Technologie (KIT), 76128 Karlsruhe, Germany, email: Physik, Karlsruher Institut für Technologie (KIT), 76128 Notkestraße 85 | 22607 Hamburg Germany http://www.desy.de/career Karlsruher Institut für Technologie (KIT), 76128 Karlsruhe, Germany, email: Phone: +49 40 8998-3392 http://www.desy.de/career [email protected]. further information about this position please contact Karlsruhe, Germany, preferably as a single pdf document Deadline for applications: Until the position is filled. Prof. Dr. Anke-Susanne Müller, email: [email protected]. by email to [email protected]. For further information Deadline for applications: Until the positions are filled. For further information information about about this this position position please please contact contact about this position please contact Prof. Dr. Thomas Müller, Reviewing of the applications will start on May 11th, 2020. Prof. Dr. Anke-Susanne Müller, email: [email protected]. KITProf. – The Dr. Research Anke-Susanne University Müller, in the Helmholtz email: [email protected]. Association email: [email protected], or Prof. Dr. Margarete Mühlleitner, email: [email protected].

KIT – The Research UniversityUniversity in in the the Helmholtz Helmholtz Association Association KIT – The Research University in the Helmholtz Association

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A lvin TollesTrup 1924–2020 Remembering a visionary physicist

Alvin Tollestrup, who passed away on them, Alvin left Caltech for Fermilab, where he 9 February at the age of 95, was a visionary. I would create the first large-scale application of Fermilab joined his group at Caltech in 1960. Alvin had superconductivity. Physics at Fermilab at that helped build Caltech’s electron synchrotron, the time was limited by the energy (200 GeV) of the highest energy photon-producing accelerator at 6.3 km-circumference Main Ring. Alvin made the time. But he thought more exciting physics essential contributions to the design, testing and could be performed elsewhere, and managed to commissioning of superconducting magnets to get approval to run an experiment at Berkeley replace the Main Ring’s copper ones – doubling Lab’s Bevatron to measure a rare decay mode the energy. The new machine, to be known as of the K+ meson. the Tevatron, was completed in 1983. Alvin went Alvin asked me to help design, build and test on to convert it to a proton–antiproton collider a new type of particle detector called a spark in 1987, which led, within a decade, to the dis- chamber. In retrospect it was remarkable that he covery of the top quark. Alvin was the primary was willing to risk the success of his experiment spokesperson for the CDF collaboration from on the creation of new technology. He also asked 1980 to 1992, and his critical contributions to me to design a transport system of magnetic the Tevatron were recognised in 1989 with a US lenses that would capture as many K mesons as National Medal of Technology and Innovation. possible. I did my calculations on an IBM 709 at UCLA – Alvin checked them by tracing rays at Virtuosity with modesty his drafting table. When the beam design was The virtuosity required to create new acceler- completed and the chain of magnets was in place ators sometimes exceeds what is necessary to o n t h e a c c e l e r a t or flo or, A l v i n t h r e a d e d a s i ngle Alvin Tollestrup led the design of the run the resulting Nobel prize-winning exper- wire through them from the thin window of the superconducting magnets for the Tevatron. iments. Alvin once told me that the Bevatron’s accelerator to our hut. director, Ed Lofgren, never got the recognition The virtuosity he deserved. The Bevatron was designed and Zen master built to find the antiproton, and sure enough I had no idea what he was doing, or why. Around required to create Segrè and Chamberlain found it as soon as Alvin the Zen master, I didn’t say much or ask the machine was turned on, earning them a many questions. After turning the magnets new accelerators Nobel prize. Alvin also didn’t get the recogni- on and running current through the wire, the tion he deserved. His modesty only exacerbated wire snapped to attention, tracing the path a sometimes exceeds the problem. K would follow from where it left the accel- what is necessary There were some things I could never learn erator to where its decays would be observed. from Alvin. His intuition for electronics was Calculations – how much current was required to run the resulting beyond my grasp, a gift from the gods. In the in the wire – followed by testing, were Alvin’s 1950s, when the giants of the day were trying modus operandi. Nobel prize-winning to understand the origin of parity violation, When run-time arrived a couple of months his knowledge of photomultipliers led him to later, the proton beam was steered into a tung- experiments discover a flaw in an experiment which, once sten target behind the thin window through fixed, validated the V–A theory of the weak which the Ks would pass. We waited for the interactions. scintillation counters to start clicking wildly, but sufficient reason, and persistent. A l v i n d i d n o t s u ffe r fo ol s g l a d l y, b ut o ut s i d eof nothing happened. Eventually, having calmly Alvin was my first thesis advisor. When he work he created a community of collaborators, persuaded the operators to shut the machine taught me how to think about my measurements, an extended family. He fed and entertained us. down, Alvin took a pair of long tongs and pressed he also taught me how to analyse and judge the His pitchers of martinis and platters of whole a s m a l l s q u a r e o f d e nt a l fi l m a g a i n s t t h e r a d ioac- measurements of others. This was essential in hams were memorable. Legendary tightrope tive target. When developed, it showed a faintly understanding which of the many “discover- performer Karl Wallenda is quoted as saying, illuminated edge at the top of the target: the ies” of hadrons in the early 1960s were believ- “Life is on the wire. The rest is waiting.” Alvin Bevatron surveyors had placed the target one able. Without his influence, I never would have showed us how to have fun while waiting, and inch below its proper position, a big mistake. discovered quarks (aces), whose existence was shared a long and phenomenal life with us, both But there was no panic or finger pointing, just later definitively confirmed in deep-inelastic off – and especially on – t he high w ire. measurement and appropriate action. That was scattering experiments. Alvin’s style, always diplomatic with manage- More than a dozen years later, true to his George Zweig Research Laboratory of ment, never asking for something without belief that users of accelerators should improve Electronics MIT.

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PEOPLE OBITUARIES PEOPLE OBITUARIES

M arcello cresTi 1928–2020 RobeRt Klapisch 1932–2020 A passion for the elementary and cosmic A life dedicated to science and solidarity CERN Marcello Cresti, a leading researcher in cosmic- Cresti family of the electromagnetic calorimeters and a wire Robert Klapisch, a former director of research ray and elementary-particle physics, former chamber. In the late 1980s he joined the DELPHI at CERN, passed away on 21 March. Robert was rector of the University of Padua, and grand experiment at LEP, with his group leading the a tireless worker, not only passionate about the officer of the Italian Republic, passed away in construction of the end-cap electromagnetic field of fundamental physics, covering both Padua on 2 January, aged 91. calorimeters. Full professor at Padua since 1965, nuclear and particle physics, but also ever eager Born in Grosseto, Cresti graduated at the Marcello was the dean of the science faculty from to hear about innovative developments in any Scuola Normale Superiore in Pisa in 1950, and 1981 to 1984 and rector of the university from scientific field. His motto was always: progress in 1951 moved to the Padua Physics Institute 1984 to 1987. From 1971 to 1973 he chaired the through science. Once a goal had been set, he directed by Antonio Rostagni. Working until CERN Track Chamber Committee, responsible p u l l e d o ut a l l t h e s t o p s t o a c h i e v e it, fol l o w i n g a 1954 at the high-altitude cosmic-ray observa- for bubble-chamber physics. w e l l- d e fi n e d p a t h, s up p or t e d b y t h e c o u r a g eof tory on the slopes of the Marmolada moun- During the final part of his career Marcello his convictions, an infectious enthusiasm and tain, he developed and used a setup including r e t u r n e d t o h i s fi r s t p a s s i o n: c o s m i c r a y s. F rom tenacity at every turn. The many facets of his two Wilson chambers in a magnetic field. In 1989, with his group in Padua and a group from personality made Robert an endearing friend and 1955 he was at the Max Planck Institute for Phys- Pisa, he designed and carried out an experi- a highly appreciated colleague. Open-minded, ics in Göttingen, directed by Werner Heisenberg, Marcello Cresti at the Max Planck Institute for ment – CLUE – aimed at the detection of high- s u p p or t i v e o f o t h e r s, c o m m it t e d, l o y a l a n d w it h and developed a technique for reconstructing Physics in Göttingen in 1955 with the “G1” – energy cosmic gamma rays; this started the an irresistible joie de vivre, h e w a s a fi n e e x a m pl e events that used one of the first electronic one of the first automatic calculators. Italian astrophysical activity at the Roque de los of a human being. computers. The following year he moved to the Muchachos observatory in the Canary Island of Robert was born on 26 December 1932 in University of California Radiation Laboratory and analysis of bubble-chamber film. Relevant La Palma. He retired in 2000. Cachan, France. After studying at the École at Berkeley, in the group of Luis Alvarez, which results were obtained on antiproton annihila- Marcello is survived by three daughters, supérieure de physique et de chimie industri- was leading the development of hydrogen bubble tions and meson resonances. Diana, Lucia and Paola. Two leading research elles ESPCI in Paris, he went straight on to join chambers. Here he discovered parity violation In 1975/1976 Marcello created a low-energy groups in Padua continue his activities, respec- the CNRS in 1956. At the Radium Institute he in the absence of neutrinos in Λ decays. antiproton beam with excellent monochroma- tively, on accelerator (LHC) and cosmic-ray became proficient in mass spectrometry and In 1958 Marcello returned to Padua, where he ticity and collimation at CERN, and measured physics. His students and friends remember his precision isotopic separation under the super- Robert Klapisch carried out pioneering research using online mass spectroscopy and also worked designed and built the first electrostatic separa- the antineutron mass with, what is still today, enthusiastic, fascinating and generous way of vision of his mentor, René Bernas. Later, Rob- to encourage sustainable development. tor in Europe to work with an antiproton beam the best precision. Beginning in 1976 he also teaching, and his witty and funny conversation. ert became the director of CSNSM (Centre de at CERN, and created the hardware and soft- contributed to the European Hybrid Spectrom- spectrométrie nucléaire et de spectrométrie de sustainable development in countries around ware structures to enable automatic measuring eter at CERN’s SPS, where his group made one His friends and students. masse) and transformed it into an innovative Robert gave the t h e M e d it e r r a n e a n a n d i n A f r i c a b y t r a n s fe r r i n g centre of excellence producing many applica- study of antimatter and developing scientific knowledge. Thanks TaTiana Fabergé 1930–2020 tions for mass and nuclear spectrometry. to the efforts of the foundation, and of Robert a decisive boost himself, students from Morocco and Palestine Pioneering spirit were able to participate in CERN’s technical and A CERN institution and force of nature To g e t h e r w it h h i s t e a m, R o b e r t c a r r ie d o ut pi o - with the construction doctoral student programmes. These students n e e r i n g r e s e a r c h u s i n g “o n l i n e” m a s s s p e c t r o s- are now assistant professors back in their own Tatiana (Tania) Fabergé, the head secretary of the CERN copy on accelerator beams, notably at CERN’s of the LEAR countries and are ideal ambassadors for CERN’s CERN theoretical physics department from 1957 Proton Synchrotron (PS) and then at ISOLDE. antiproton ring culture of international collaboration. In addi- until her retirement in 1995, passed away peace- At this brand-new online isotope separator, tion, with a view to creating a friendly space for fully on 13 February, shortly before reaching 90. the team also carried out the first ever laser discussions at SESAME, the international centre Tania was the great-granddaughter of Peter spectroscopy, which, when combined with mass for synchrotron-light experimentation in the Carl Fabergé, jeweller to the 19th-century Russian spectroscopy, enabled unprecedented studies Middle East, Robert convinced the foundation Imperial Family. Born stateless to exiled parents of exotic short-lived nuclei. This work allowed After returning to France, Robert participated to finance a ca feteria t here! in Geneva, she trained in design and worked in them to make significant advances in the fields in the group led by Rubbia that was carrying the family tradition for a few years. Then, in 1957, of astrophysics (nucleosynthesis of rare light o ut r e s e a r c h i nt o a n i n n o v a t i v e a p pr o a c h t o t h e Humanism and solidarity teams of CERN theorists from Copenhagen and elements) and nuclear physics (exotic nuclei). pr o d u c t i o n o f nu c l e a r e n e r g y a n d t h e pr o c e s s i n g A s w e l l a s b e i n g a n e x c e p t i o n a l s c i e nt i s t, R o b e r t Geneva were merged to form, on the new Meyrin These techniques are still used at ISOLDE today. o f nu c l e a r w a s t e t h r o u g h t r a n s m ut a t i o n. M or e knew how to enjoy life. He was fond of a good site, what is now called the theoretical physics R o b e r t s e r v e d a s d i r e c t or o f r e s e a r c h a t C E R N recently, he lent his support to initiatives on celebration, and a fan of fine food and wine, in department. The new group needed a secretary, from 1981 to 1987, a period in which the research the transport of electrical energy by supercon- particular Burgundy wine, of which he was a and Tania’s personality and talent for languages Tatiana Fabergé in her realm. programme at the SPS proton–antiproton ducting cables. great connoisseur. Many of us had the pleas- (she eventually mastered seven) won her the job. collider was in full swing. The crowning glor y I n 2004 R o b e r t l a u n c h e d t h e “S h a r i n g K n o w l- ure of tasting some with him during animated She went on to become a pillar of theoretical hallmark of the theoretical secretariat. the Russian Orthodox Easter and her name days. of this programme was the discovery of the edge” series of conferences, which brought discussions on science, politics or society in physics at CERN for decades, as the group grew Tania was a talented artist and actress, whose Following her retirement, Tania embraced W and Z bosons in 1983 and the award of the together numerous scientific experts from g e n e r a l. R o b e r t w a s a g e n e r o u s m a n a n d h i s d o or and evolved, and the secretariat expanded. There theatrical appearances in many theory Christmas a new calling. She trotted the globe for many Nobel Prize in Physics to Carlo Rubbia and Simon a r o u n d t h e M e d it e r r a n e a n. T h e s e c o n fe r e n c e s, w a s a l w a y s w i d e o p e n. He w a s a l s o a n e x p e r t i n were 10 department leaders and 10 Directors- pantomimes were highly appreciated. Outside years, connecting with far-flung members of van der Meer the following year. During his the last of which took place at CERN in 2019, many cultural domains: literature, art, theatre General while she was at CERN. During this time the lab, for many years Tania helped administer the Fabergé clan, preserving the family heritage, mandate, Robert gave the study of antimatter a covered many subjects, from the digital divide and cinema. The best way to pay tribute to him she welcomed thousands of visitors to the theory physics schools on the Adriatic coast of what was protecting its name, and writing several books d e c i s i v e b o o s t w it h t h e c o n s t r u c t io n o f t h e L E A R to satisfying humankind’s basic needs (water, is to continue to promote his ideals of humanism group, and generously helped them settle in at then Yugoslavia. Her home in Versonnex became of reference about her great-grandfather’s work. antiproton ring and the start-up of a rich and energy, food). They were always a resound- and solidarity. CERN. With her robust sense of humour and col- a second home for Russians working at CERN. She Her spirit lives on. diverse physics programme. He also launched ing success. To ensure the lasting impact of O u r t h o u g ht s a r e w it h h i s f a m i l y, p a r t i c u l a rl y ourful character that nobody could ever forget, often held open houses, not only for theorists, the relativistic heavy-ion collision programme these conferences, in 2006 Robert created the his three children, Coline, Cédric and Marianne. she was a CERN institution and a force of nature, but also for many others in the wider CERN com- Marie-Noëlle Fontaine, Nanie Perrin and that led to the discovery of a new state of matter “Sharing Knowledge Foundation”, which he setting the friendly tone that has long been a munity, in particular legendary parties marking John Ellis CERN. a t h i g h t e m p e r a t u r e s, t h e q u a r k–g lu o n pl a s m a. directed for 15 years, working to encourage His friends and colleagues at CERN and CNRS.

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Notes and observations from the high-energy physics community Straight to video From the archive: May 1980 Grand unification … Recent successes of the electroweak theory have made theorists confident enough to CERN 271-3-79 CERN tackle ‘grand unifications’ of strong interactions with the electroweak force. One prediction is that protons can decay with a lifetime of some 1031 years. This means that a man [sic!] would Virtual success Danielle Speller of Yale presents CUOR E’s latest results on have to live for more than a neutrinoless double-beta decay at the APS virtual April meeting. century before he could say that there was a good chance that just Murray Gell-Mann describes ideas As COVID-19 keeps labs and universities in lockdown, and one of the protons in his body on the “grand unification” of strong, videoconferencing becomes even more ubiquitous than before, in our had disintegrated. weak and electromagnetic forces at globalised field of virtual perma-jetlag, an intriguing phenomenon The apparent absence of CERN in 1979. is being noticed, at least anecdotally: a greater enthusiasm for magnetic monopoles when the meetings. Though further data are needed to confirm the effect, equations of electromagnetism are symmetric with respect to teams both big and small are seeing a higher than usual participation electric and magnetic charge has long intrigued physicists. The in presentations and colloquia. ‘grand unification’ theory argues for the existence of such Although nothing can replace the cut and thrust, especially for monopoles, heavier even than the bosons held responsible for proton young researchers, of eyeballing your inquisitor, or cornering an expert decay, much heavier than a bacterium! If such superheavy over coffee, con ferences are adapt ing quic k ly. The April A PS meet ing, monopoles were produced in the extreme temperatures of the Big originally due to be held in Washington, DC, was in full swing virtually Bang, they should still be around. as the Courier went to press, with 7000 participants tuning in – 5800  Compiled from text on pp114–115 of CERN Courier May 1980. more than the number who had registered to attend – and an almost full programme. Organisers of IPAC 2020, due to take place at GANIL Compiler’s note from 10 to 15 May, LHCP in Paris (25 to 30 May) and Neut rino 2020 in 40 years on and neither proton decay nor real Chicago (22 to 27 June) are also work ing out v ir t ual for mats on t he magnetic monopoles have been observed. Monopoles same dates. If the current videoconferencing competence continues, are rather like zero-length pieces of string, more easily physicists’ pangs of guilt at their disquieting carbon footprints may imagined (by theorists?) than described (for become increasingly difficult to ig nore in t he post-pandemic world. experimentalists?), making it difficult to know what to look for. As for proton decay, with a half-life of some 31 The approximate number of 10 years there would be about one event per week, scientific observations in the with a fairly distinctive signature, in a tank containing 1000 tonnes of water. Easy to describe, challenging to implement. The principal problem Hubble MAST data archive, is cosmic and geological background, so the tank must be buried a 550,000 released by NASA to celebrate kilometre or two deep in Earth’s bedrock and covered in veto counters. the 30th year in orbit of the Nonetheless, although tricky, searches for these two elusive phenomena Hubble Space Telescope continue, so watch this space, or rather watch this journal.

Media corner “The increase [in the brilliance of light sources] Theorist Anthony Zee quoted in Quanta Magazine by a factor of about 10 22 from the mid 1960s (30 March) about a recent preprint by Steven “The scientific case for the future of experiments to the present gives the average doubling Weinberg (arXiv:2001.06582) addressing the in particle physics – accelerator-based or not time of about eight months – three times as mysterious hierarchy of fermion masses. – is strong… Scientific merits aside, convincing fast as for transistors and six times as fast as the politicians and the public that it’s worth the luminosity of colliders.” investment might be harder… However, a “We analysed simulated data of Higgs utilitarian argument that emphasises the Vladimir Shiltsev writing in the April issue experiments with the aim of identifying the most innovation, skills and technology that come of Physics Today about advances in suited quantum machine-learning algorithm out of a healthy infrastructure for particle accelerator physics. for the selection of events of interest.” physics is compelling.” Panagiotis Barkoutsos of IBM Research quoted From an editorial in Nature Physics (6 Apr i l) “Weinberg’s paper is a bit of lightning in in Physics World (3 April) on a collaboration devoted to the European strategy for particle the dark. All of a sudden a titan in the field is between IBM and CERN openlab to explore physics (Nat. Phys. 16 369). suddenly working again on these problems.” quantum computing in high-energy physics.

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Cosmic Hunter NEW SP5620CH Science Passion Creativity When CAEN technology meets young talents

Experiments Cosmic Hunter is a new educational tool • Cosmic Muons detection through which CAEN wants to inspire young • Coincidence (single, double and triple) students and guide them towards the • Zenit angle dependance analysis and comprehension of cosmic rays. • Cosmic Shower Detection Cosmic Hunter SiPM based, is composed of one detection - coincidence unit together with two plastic scintillating tiles. A third tile is available on request. Muons detections, flux estimation, shower detection and more are allowed thanks to a flexible system geometry.

Ascent commemorates cosmic-ray pioneers At the 42nd international balloon festival in Château-d’Oex, Hans Peter Beck (University of Bern and Fribourg) ascended on January 25th with some of his students up to 4000m in a hot-air balloon, commemorating the historic flight of Albert Gockel from 1909 (with modern equipment using CAEN Cosmic Hunter), measuring cosmic rays.

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