PoS(ICHEP2020)039 https://pos.sissa.it/ ∗ 0, [email protected] Speaker ∗ Fermi National Accelerator Laboratory, PO Box 500, Batavia, IL 60510, USA E-mail: Particle accelerators are arguably thephysics most needs effective continuously tools push for us the to particlemance invent physics of novel research. ways accelerators, to reduce increase The their energyoverview three cost and main improve and families perfor- make of them modern and moreators future for power accelerators neutrino efficient. for research, HEP particle – Here factories high wepost-LHC for intensity briefly energy the acceler- frontier electro-weak physics colliders and – Higgs andR&D studies, topics discuss and and corresponding objectives. ongoing or planned accelerator Copyright owned by the author(s) under the terms of the Creative Commons 0 © Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND 4.0). 40th International Conference on High EnergyJuly physics 28 - - ICHEP2020 August 6, 2020 Prague, Czech Republic (virtual meeting) Vladimir Shiltsev Accelerators for HEP: Challenges and R&D PoS(ICHEP2020)039 neutrino and Vladimir Shiltsev (1 MW). superbeams $ , MW Year 1 % 13 , 10 ??? # , s 2 2H2;4 ) 30 1.1670 43 7 1.3 25 2028 0.45 ca.2035 , GeV 1  luminosity and some 1 TWh of annual electric energy consumption. Here 1 − s 2 Modern and future proton accelerators for high energy neutrino research. − -Factory 5 0.02 10 4 (tbd) a cm SB 2 0.071 110 5 ca.2030 a 34 10 STORM 100 3.6 4 0.16 (tbd) · Table 1: a FNAL MI(PIP-II)(PIP-III)J-PARC 120 120ORKA/P 1.33 120 30 1.2ENUBET 1.2 5.2 2.4825 GeV 70 7.6 0.766 15 400 25 2020 7 1.2 5.8 2.4 0.515 2027 2030’s 5 2.25 2020 0.51 0.09 ca.2026 (tbd) Facility ESS . Superbeams [4] are based on conventional beam dump technique: an intense high energy At present, the leading high-energy high- power accelerators for neutrino research are rapid Growing demands of the high energy physics call for more powerful, more productive and The main types of accelerators for high energy neutrino research are At neutrino factories, 20 to 50 GeV muons generated in pion decays same way as in superbeams, cycling synchrotron (RCS) facilities J-PARC in Japanproton which beam has power reached 0.515MW [6], of and the the 30 GeV Fermilab Main Injector delivering up to 0.766MW of 120 GeV more sophisticated particle accelerators.out diverse Many accelerator beam R&D physicists not andaddress critical only accelerator questions and to issues engineers related push to carry the theefficiency feasibility of performance of energy, cost, various of performance, future and existing accelerators. power machines, Particularlybeyond challenging but current are "state-of-the-field" also represented the by to proposed the facilities Large Hadron thatper Collider go beam, with its 2 6.5 TeV energy are stored in a storage ringneutrino with beams long with straight a sections precisely [5]. known mixture Decaying of muons neutrino produce types. well-directed Accelerators for HEP: Challenges and R&D we overview modern and futureweak factories high and intensity multi-TeV energy accelerators frontier forof colliders neutrino corresponding and research, accelerator outline Higgs/electro- main R&D. directions Ourreports and presented analysis at objectives mostly this follows ICHEP20201–3] Refs.[ conference. and references many 1. High Intensity Accelerators for Neutrino Research factory proton beam is directed ontocaptured a by thick an nuclear optical target producingcharge system secondaries. mostly of pions magnetic High-energy and neutrino horns kaons, beamskaons in which are in order are a products long to of decay the obtain channel. decaysthe well Superbeams of mechanical strive directed charged stability to pions beam limit operate of and with of the a same primary proton beam targets which intensity is closer at to present PoS(ICHEP2020)039 = 1 % as 2H2;4 ) Vladimir Shiltsev 55% ) [12]. ∼ , but requires (often - 2 VW ∼ ? and cycle time # 1 W/m while increasing intensity ∼ ??? , # . In reality, the repelling forces of the proton ) W 3 ??? is to increase the beam energy. That would require # 1 /( % , ∼ STORM - see1. Table The latter will represent the first step a 1 % / and is also synergistic with world-wide muon collider accelerator . Average proton beam power on the neutrino target scales with , ) ≤ ??? # , number of particle per pulse (PPP) / 1  . One way to increase ??? neutrino factories # 2H2;4 Δ ) ( superbeams facilities Intensity-dependent fractional FNAL Booster 400 MeV proton beam intensity loss shortly after )/ ??? . That requires the fractional beam loss scale down with increase of beam intensity, energy The needs of neutrino physics call for the next generation, higher-power, megawatt and multi- The beam power can also be boosted by increasing the PPP - then, the key challenges will be # 1 ???  ( # SRF) injection linacs; ii) to employ larger aperture magnets which would allow certain blowup of the beam energy either better or new magnets andnew RF magnets acceleration and system, and/or RF to mightof decrease the the be cycle facility needed) time AC – (again, power thatmachine consumption. designers usually and There engineers implies for are high the power several cost upgradesSC approaches and and magnets, actively future machines significant pursed like such increase by as 4 more thecables efficient T/s RCS [9] ones or 12 for T/s the HTS-basedalternating FAIR magnet gradient) project prototype accelerators recently in [11]; tested Darmstadt also, atwith FNAL under (Germany) capacitive [10]; development built energy FFAG are (fixed with storage more field and NbTi efficient80% recovery, power SC efficient and supplies klystrons, on magnetrons, and more solid-state economical ones RF (compare to power current sources such as MW-class mostly associated with numerous beam dynamics issuesPPP and, challenge sometimes, is with about the how to cost. control The the utmost beam losses below and power Figure 1: injection vs total number of protons (from [8]). beam’s own space-charge lead to increase of beam sizes- and particle see losses at1. Fig. higher beam intensities Acceleratorinjection R&D energy explores into several the lines RCS of - attack that on allows the to problem: gain the i) intensity to increase the physics R&D activities (see below). Accelerators for HEP: Challenges and R&D protons [7]. There areProtvino/ORKA, several ENUBET, and promising the new proposalstowards under future consideration including ESSvSB, PoS(ICHEP2020)039 which =3 ; vii) to % Vladimir Shiltsev Beta-beams He with half-lives of 6 D and conceptual design & Ne or 18 ) muon decays per year [17]. The NF 21 STORM is the idea of a =24, or in the J-PARC MR with (shaping) of the beams via charge-exchange (10 % $ 4 [14]. The last two approaches are novel and are being elements to reduce the losses [13]; viii) to employ electron transverse painting without the beam halo hitting the aperture and resulting in the losses - STORM facility is production of neutrino beams from the decay of 1 GeV/c f a irradiation (due to the particles which might avoid dedicated collimators or ; iv) to use the 5  space-charge compensation -decay of relatively short-lived radio-isotopes such as V Non-Linear Integrable Optics particles by foils or lasers), electron cloud effects and coherent beam instabilities. uncontrolled − The basic idea for The neutrino factory (NF) concept envisions very high intensity neutrino and antineutrino In all scenarios, one would need reliable targets and horns to shape the secondary beams. There Big number of the future colliders proposals has been brought up in the course the 2020 Euro-  to 6 GeV/c muons incooling a and racetrack-like decay acceleration ring, [20, i.e.,21].a like large in The diameter a major (0.5 neutrino challenges factory m)focusing of but magnets lattice the without which to proposal should muon accept assure are most survival a)rms of of necessity about beam the to 60% momentum secondary of have spread. muons, muons after and 100 Conceptually b) turns close a with to sophisticated the 10% introduce lenses for the optimization [18, 19]. beams which are exact CP conjugates - a total of tested at the dedicated IOTAthe ring RCSs at for HEP, Fermilab such [15]. as efficientoff injection There of are high other power beams intensity (that dependent requires issues stripping electrons in the challenge is that due toof the the radiation targets damage gets and worse thermal (shorter) shock-waves,pose the with operational serious the lifetime power impediment increase and onabout frequent facility’s replacements 0.8 uptime. of MW them beam may Existing power,prototyping. while neutrino MW Ongoing targets and R&D and multi-MW program targetsfibers), horns includes are new are target studies under designs good of active (e.g., development to material rotating and or properties, liquid new targets) [16]. forms (foams, dumps and scattered around the ring); vi)like in to the make the Fermilab beam Booster RCS focusing with lattice periodicity perfectly periodic, of e.g., pean Particle Physics Strategy Updateprocess discussions [22]. [3] and2 Fig. thepresents 2021 proposed Snowmass timelines US of HEP some planning of them. Linear collider Higgs/EW fac- Accelerators for HEP: Challenges and R&D the transverse rms size that might be expensive; iii)RF to and flatten reduce the beaminjection current to pulse linearize shape the by space-chargelower using forces; the v) 2nd to harmonics design better efficiency collimation system to performance depends on thecooling. power of The the ionization proton cooling driverpractical method and implementation though the challenges relatively degree such straightforward inaccelerating or as gradients principle, in absence RF relatively low has frequency of breakdown normal-conducting some RF the suppression cavities immersedmagnetic muon in and strong fields. attainment of While key high accelerator NF technology and beam cost feasibility physics issues are challenges subject have of ongoing been R addressed, several important exploits the around 1 s which are ionised, acceleratedwhere to they relativistic eventually speeds decay and [17]. put into a racetrack storage ring, 2. Colliders for Electro-weak and Higgs Physics PoS(ICHEP2020)039 nanobeams Vladimir Shiltsev 5 Higgs factories, such as FCCee and CEPC [25] have satisfactorily − 4 + 4 Plans of operational high energy particle colliders and approximate technically limited timelines IP scheme. Common for these linearthe and terms circular of colliders luminosty is per the TWh energy efficiency of concern, the e.g., wall-plug in electric energy consumed (see4). Fig. Figure 2: of future large colliding beam facilities (from [2]). addressed general feasibility issues, theystage have of accomplished developments toward CDRs TDRs to and prototypematters now major of enter critical financial systems the and feasibility, multi-year to realistic address timelinesthese in machines and detail are expected the related performance. to the Majoras cost, challenges well driven of as by the the SRF energy systems,the efficiency magnets, site as and electric at civil power. construction; present Strong theseand international projects their R&D foresee main the collaborations R&D are need in priorities ofefficiency place, about include CW e.g., 300 [26]: SC the MW cavities; FCC 1) of team, 2)booster development magnets; of energy 80% recycling/storage 3) systems efficient non-linear for klystrons focusingfects, high and lattice beamstrahlung and efficiency high and imperfections rapid and beam the cycling dynamics dynamic analysis aperture optimization with with beam-beam the ef- Accelerators for HEP: Challenges and R&D tories, such as 250 GeVbeing c.m.e. at the ILC readiness] [23 levelDesign and of Report CLIC the (CDR), [24] respectively. Technical Design All are their Report"ready-for-approval" among and major pre-construction (TDR) the R&D project readiness have most stage. been and advanced Besides completed the large projects, the and scale Conceptual they SC operation are of or in thousands NC the RFdependent units, on their efficient positron major production concerns (exceeding by areachieved more mostly at than about an the order their SLC of luminosity, magnitude - whicheffectively the see is level operate3) Fig. strongly these and machines, the which anticipatedNote also, commissioning are the time very the CLIC needed sensitive two-beam to to accelerationbackup learn scheme option. ground is how novel motion to and and the Circular project other has noises. klystrons-based PoS(ICHEP2020)039 Vladimir Shiltsev colliders (from [2]). 6 − 4 + 4 Positron production rates achieved at the SLC, KEKB and SuperKEKB compared with the need The most critical requirement for the post-LHC energy frontier colliders is the center-of-mass Development of a representing magnet with up to 16T maximum field is arguably the hardest Muon colliders with cme up to 14 TeV – see5 Fig. – offer about factor of 7 advantage in Figure 3: for top-up injection at future circular and linear energy reach and there areTeV HE-LHC five [27], leading 3 to proposals 14 (in TeV Muon order CollidersThe [28], of [29], construction the [30], cost 75 energy TeV SppC is reach): and the 100and 3 TeV FCC-hh. lowest FCC-hh, TeV for all CLIC, the within 27 a HE-LHC factor and offor 2 the the to HE-LHC Muon 3 and [2]. Collider, the followed The Muon byfactor required Collider, of CLIC-3 AC followed site 2 by power ILC, consumption to is then 3. theof by lowest readiness, FCC-hh As the and for CLIC-3 CLIC, the project all required would withinrequired need duration a for some and the 10 scale HE-LHC, years of FCC-hh/SppC, of R&D, and the while for R&D about the effort twice Muon that Collider. to time reach is thechallenge for TDR the level hadron colliders in viewdensity of in fundamental challenges superconductors in and getting thestresses in required in current dealing the with the superconductorNb3Sn, ultimate and 14 magnetic associated T pressures components. to and 1615 mechanical It T years of magnets is prototyping/pre-series will estimated with requirefield that industry 10-15 strength development [3]. years for of for a The short-model superconducting2020. current R&D, accelerator world The followed dipole record SppC by magnet team of 10 was plans 14.5 to achieved toan by Teslas explore iron-based for feasibility Fermilab superconductor. of team an in alternative Other low-costefficient challenges, 12 intercept demanding T of dipoles substantial the built synchrotron R&D with radiation effortsand power safe (5 include: collimation MW a) in of FCC-hh the /power; ultra-high c) 1 energy non-linear MW lattice beams SppC); studies with to b) increase some precise dynamicor 7 aperture a times at new injection the 3.3 (either LHC TeV 1.3 SC TeV circulating SC-SPS injector);etc. beam d) optimal IR design and MDI (machine-detector interface) studies, Accelerators for HEP: Challenges and R&D 3. Energy Frontier Multi-Tev Colliders PoS(ICHEP2020)039 and 1 − B 2 − cm 34 Vladimir Shiltsev 10 · (10%) reduction of transverse emittance of $ 7 /TWh efficiency, smaller size and cost [31]. However, muons are produced as 1 − Energy efficiency of present and future colliders. Annual integrated luminosity per Terawatt-hour A CERN-led international collaboration is being formed to bring together the diverse expertise and complementary capabilities fromgeneration around energy-frontier the discovery machine. world The to objectives of realizein the the about collaboration are muon 4 i) collider to years, develop, as the the CDR next- of a baseline 3TeV collider with a luminosity of 2 the potential mass reach forbecause the of better exploration ab of the energy frontier, in addition to being attractive initially dispersed 140 MeV/c muons passing throughof an a ionization cooling sequence channel cell ofthat consisting LiH provide the or required liquid particleproduction Hydrogen and focusing 6D [33]. absorbers cooling; within ii) Furtherand fast a machine R&D acceleration detector (magnets, interface, is lattice iv) RF), required large of aperture iii) on: 12 detectorthe up T radiation background SC i) magnets, to effects reduction v) effective of countermeasures 3.5 neutrinos, muon to minimize produced T by decaying solenoids muons. Figure 4: of electric power consumption asexpected a after function its of high-luminosity theparticle upgrade centre-of-mass colliders, (black energy. as diamonds) The taken —electron-—positron LHC from is Collider — reference contrasted (FCC-ee, both [2]: with magenta presentInternational circles) a and the Linear assuming variety Muon Collider (ILC, experiments of Collider blue at circles), proposed (MC,Energy the two LHC red Compact collision (HE-LHC, Linear circles), magenta points, Collider diamonds), (CLIC, the and the cyan the circles), Futurediamonds). Future the Circular Circular The High proton–proton effective Collider energy (FCC-hh, reach green offactor of hadron colliders seven lower (LHC, than HE-LHC that and of FCC-hh) a is lepton approximately collider a operating at the same energy per beam (from [31]). secondary particles and decay rapidly, sothat they have presents to a be collected, special cooledrequired challenge and to for accelerated overcome rapidly a this challenge collider.demonstrated are that within Recent the our research liquid grasp. indicates Mercuryof The that 4MW target MERIT power the system experiment and can technologies at more sustainat CERN [32]. an RAL has intense The (UK) primary International has proton Muon recently Ionization beam demonstrated Cooling effective Experiment (MICE) Accelerators for HEP: Challenges and R&D PoS(ICHEP2020)039 − 4 + 4 Higgs W − W Vladimir Shiltsev of luminosity than the 1 − ) of luminosity at 1.2/3.2 TeV c.m.e.; 1 (the discovery potential of the >10TeV − 1 − B 2 (1 ab for the Higgs production, but require further − $ − cm 4 8 35 10 · ’s, positrons and muons; following recent proof-of-principle W concept [37] collision of high intensity laser with the LHC ions (1 GeV) $ Gamma-Factory Schematic layout of a 14 TeV muon collider complex. The muon injector systems include the Many innovative accelerator concepts are now under active exploratory studies. Among them FCCee; main challenges of suchbeam emittances approach as are well the as needseeks strong acceleration for beam-beam of generation effects; electrons and ii) in three ERL-based controlto turns LHeC of collide to (or very 30-60 with FCCeh) GeV the small by [35] LHC/FCCpp SC also protons RFextensive and sections tests in deliver of a the new ERL 6 technology kmFactories are tunnel [36] planned at require the collisions PERLE of facility only at 80 Orsay; iii) GeV demonstration, possibilities of significantly higher fluxes are being considered. results in generation of are: i) Energy Recovery Linac (ERL) based FCCee [34] assumes 100 km long 240 GeV cme machine would be competitive to orevaluated exceed at that the of moment), any ii) otherstudies, to energy and construct frontier iii) a collider to option comprehensive come facility being up with for a the Technical most Design relevant Report tests by and the end of 2030’s. collider, that brings particles’accelerating energies sections up and in promises some just 3-10 several times turns less RF employing power 60 per ab GeV per turn SRF R&D on the designetc; of iv) such in recirculating the linear accelerator facilities, on the high power lasers, a 10-14 TeV collider with a luminosity of 4 Figure 5: proton driver, a high-powerinteractions target with system the with target, atogether, a a capture muon pion ionization solenoid cooling decay channel for channel, thatby the provides where more cooling pions for than muons both generated five positive are orders and by negative collected ofenergies muon the magnitude, and beams up a proton subsequently to low bunched energy 30 muonmuon GeV, accelerator followed beam by stage is that a transferred would into 450 delivermulti-TeV range a beams GeV and high-energy with high can accelerator possibly energy complex share injector. thatwill the be can 26.7 transferred to increase From km the the tunnel collider the ring, beam with whose injector,performance, energy the circumference, can optimized each muon to be for cost from collider the species considerations 26.7 ring. and of km luminosity toat Finally, about least the 14 two beams km detector [31]. interaction A regions 14 for collider TeV-class the ring particle is anticipated physics program. to support Accelerators for HEP: Challenges and R&D PoS(ICHEP2020)039 − 4 + 4 Vladimir Shiltsev plasma; ii) by intense electron 3 − cm 18 10 , 2030005 (2020). 9 35 (17) ); and iii) by high energy proton bunches (2 GeV over 10m 3 − , 101 (2007). , 6989 (1998). , 162490 (2019). cm 17 943 , 591–595 (2006). 10 439 (3) 57(11) , this Conference, contribution ID 775 (2020). , Proc. IPAC 2017 (Copenhagen, Denmark), pp.4842-4827 (2017) 562 (2) , NIM A , Proc. IPAC 2012 (New Orleans, USA), pp.3535-3537 (2012) , arxiv:1910.11775; The European Strategy Group, CERN-ESU-013 (2020). et al. et al. et al. et al. et al. Phys. Reports Phys. Rev. D ). In principle, plasma-based linear accelerators can be employed for high energy 3 − cm 15 Particle acceleration by plasma waves has enormous promise for unmatched gradients and may I greatly appreciate my long-time collaboration with F.Zimmermann of CERN on the entire Fermi National Accelerator Laboratory is operated by the Fermi Research Alliance, LLC under 10 [5] S. Geer, [1] V.Shiltsev, Modern Physics Letters A, [2] V.Shiltsev, F.Zimmermann, arxiv:2003.0908 (to appear in Reviews of Modern[3] Physics, 2020) R.K.Ellis, [4] S. Kopp, [6] S.Sekiguchi, [7] T.Jones, this Conference, contribution ID 913 (2020). [8] V.Shiltsev, J.Eldred, V.Lebedev, K.Seiya, Preprint FERMILAB-TM-2740 (2020). [9] E. Fischer, bunches (9 GeV over 1.3m at turn into the mostthe advanced past practical two technology. decades Impressivepulses have proof-of-principle demonstrated with experiments three energy of effective gains ways up to to excite 4.3 plasma: GeV over i) 9 by cm short in laser Accelerators for HEP: Challenges and R&D at [11] Y.Mori, NIM. A, [12] V. Yakovlev, spectrum of issues related to modernwidely and cited future here. colliders, that Very resulted(SLAC), helpful D.Denisov in (BNL) were and the M.Narain also recent (Brown University) review discussions within article theprocess. with US Snowmass’21 S.Gourlay planning (LBNL), T.Raubenheimer Contract No. DE-AC02-07CH11359 with the United States Department of Energy. References [10] H. Piekarz, colliders, but significant long-termas R&D acceleration effort of positrons, is beamstrahlung, required stagingvs to efficiency, power vibrations, address efficiency, emittance jitter many control critical andworldwide issues, which scattering are such in focused on plasma, thesethe issues etc. plasma as accelerators: well on There ALEGRO, possible BELLA, are early FACET-II, EuPRAXIA, non-collider and several applications others very of ], [38 active [39], [40]. collaborations 4. Acknowledgements PoS(ICHEP2020)039 Vladimir Shiltsev , 145 (2015). 65 , 13594 (2020). (2009). 804 , 021002 (2013). , 084002 (2010). 16(2) , (Springer, 2015). 13 (8) 10 Ann. Rev. Nucl. Part. Sci. , T06003 (2018). , 53 (2020). , 347 (2009). 59 , https://indico.cern.ch/event/765096/contributions/ 13(06) 578(7793) , this Conference, contribution ID 1001 (2020). Nature Preprint FERMILAB-CONF-10-212-APC Journ. Instr. , et al., , Phys. Rev. S. T. Accel. 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