Future Perspectives at CERN 3 Unprecedented Accuracy
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A Thermionic Electron Gun for the Preliminary Phase of Ctf3 G
Proceedings of EPAC 2002, Paris, France A THERMIONIC ELECTRON GUN FOR THE PRELIMINARY PHASE OF CTF3 G. Bienvenu, M. Bernard, J. Le Duff, LAL, Orsay, France H. Hellgren, R. Pittin, L. Rinolfi, CERN, Geneva, Switzerland Abstract A dedicated electron gun has been designed and built Table 1: Beam parameters at gun exit for the preliminary phase of the CLIC Test Facility 3 Nominal beam energy 90 keV (CTF3). The gun is based on a thermionic gridded Pulse width 2 to 10 ns cathode and operates at 90 kV in the intensity range of Intensity 0.05 to 2 A 50 mA to 2A. The specific time structure of the beam is Number of pulses 1 to 7 characterized by a burst of up to seven pulses of variable Repetition rate 50 Hz pulse width (4 to 10 ns) each separated by 420 ns, the revolution time of the former EPA (Electron Positron Emittance (rms) <15 mm.mrd Accumulator) ring. The mechanical conception was specifically designed to be compatible with the existing 2.1 Mechanical design front-end of the former LIL (LEP Injector Linac). We will The vacuum chamber of the CLIO gun has been designed describe the experimental results obtained with the beam to fit existing CERN equipment, in particular the gun is on CTF3. fully compatible with the «CERN plug-in system» and an existing pair of ion pumps. All inner elements have been 1 INTRODUCTION baked under vacuum (400 ºC, 10-5 mbar, 12 h) and assembled under clean laminar airflow. With these The Compact Linear Collider (CLIC) scheme is based precautions a pressure of 10-9 mbar was obtained very on the production of a 30 GHz RF pulse that requires quickly and the HV processing reduced to a few hours. -
Judicial Review of Uncertain Risks in Scientific Research
Chapter 6 Judicial Review of Uncertain Risks in Scientific Research Eric E. Johnson Abstract It is difficult to neutrally evaluate the risks posed by large-scale leading- edge science experiments. Traditional risk assessment is problematic in this context for multiple reasons. Also, such experiments can be insulated from challenge by manipulating how questions of risk are framed. Yet courts can and must evaluate these risks. In this chapter, I suggest modes of qualitative reasoning to facilitate such evaluation. Keywords Risk · Risk scenarios · Law · Courts · Science · Scientific research · Particle physics · Black holes · LHC 6.1 Introduction In the world of engineering, uncertainty is anathema. Whether designing a nuclear power plant or planning a system of levees, engineers do not like surprises. Exper- imental scientific research, however, thrives on uncertainty. Reaching beyond the current state of knowledge is the whole point of the enterprise. Whether probing the planets or trying to create new particles, scientists would love to see a surprise around every corner. Uncertainty goes hand in hand with aspirations to explore and discover. This special role for uncertainty in scientific research makes questions of catastrophic risk from science experiments particularly interesting. What is more, 1See Hawai‘i County Green Party v. Clinton, 980 F. Supp. 1160, 1168-69 (D. Haw. 1997); Karl Grossman, The Risk of Cassini Probe Plutonium, The Christian Science Monitor (Oct. 10, 1997) http://www.csmonitor.com/1997/1010/101097.opin.opin.1.html; CNN, Cassini roars into space, CNN (Oct. 15, 1997) http://www.cnn.com/TECH/9710/15/cassini.launch/; Najmedin Meshkati, Probability, Plutonium Don’t Mix (op-ed), Los Angeles Times (Oct. -
REPORTS on RESEARCH PL9800669 6.1 the NA48
114 Annual Report 1996 I REPORTS ON RESEARCH PL9800669 6.1 The NA48 experiment on direct CP violation by A.Chlopik, Z.Guzik, J.Nassalski, E.Rondio, M.Szleper and W.WisIicki The NA48 experiment [1] was built and tested on the kaon beam at CERN. It aims to measure the effect of direct violation of the combined CP transformation in two-pion decays of neutral kaons with precision of 0.1 permille. To perform such a measurement beams of the long-lived and short-lived Ks are produced which decay in the common region of phase space. Decays of both kaons into charged and neutral pions are measured simultaneously. The Warsaw group contributed to the electronics of the data acquisition system, to the offline software and took part in the data taking during test runs in June and September 1996. The hardware contribution of the group consisted of design, prototype manufacturing, testing and production supervision of the data acquisition blocks: RIO Fiber Optics Links, Cluster Interconnectors and Clock Fanouts. These elements are described in a separate note of this report. We worked on the following software related issues: (i) reconstruction of data and Monte Carlo in the magnetic spectrometer consisting of four drift chambers, the bending magnet and the trigger hodoscope. Energy and momentum resolution and background sources were carefully studied, (ii) decoding and undecoding of the liquid kryptonium calorimeter data. This part of the equipment is crucial for the measurement of neutral decays, (iii) correlated Monte Carlo to use the same events to simulate KL and K^ decays and thus speed up simulation considerably. -
HERA Collisions CERN LHC Magnets
The Gallex (gallium-based) solar neutrino experiment in the Gran Sasso underground Laboratory in Italy has seen evidence for neutrinos from the proton-proton fusion reaction deep inside the sun. A detailed report will be published in our next edition. again, with particles taken to 26.5 aperture models are also foreseen to GeV and initial evidence for electron- CERN test coil and collar assemblies and a proton collisions being seen. new conductor distribution will further Earlier this year, the big Zeus and LHC magnets improve multipole components. H1 detectors were moved into A number of other models and position to intercept the first HERA With test magnets for CERN's LHC prototypes are being built elsewhere collisions, and initial results from this proton-proton collider regularly including a twin-aperture model at new physics frontier are eagerly attaining field strengths which show the Japanese KEK Laboratory and awaited. that 10 Tesla is not forbidden terri another in the Netherlands (FOM-UT- tory, attention turns to why and NIHKEF). The latter will use niobium- where quenches happen. If 'training' tin conductor, reaching for an even can be reduced, superconducting higher field of 11.5 T. At KEK, a magnets become easier to commis single aperture configuration was sion. Tests have shown that successfully tested at 4.3 K, reaching quenches occur mainly at the ends of the short sample limit of the cable the LHC magnets. This should be (8 T) in three quenches. This magnet rectifiable, and models incorporating was then shipped to CERN for HERA collisions improvements will soon be reassem testing at the superfluid helium bled by the industrial suppliers. -
Trigger and Data Acquisition
Trigger and data acquisition N. Ellis CERN, Geneva, Switzerland Abstract The lectures address some of the issues of triggering and data acquisition in large high-energy physics experiments. Emphasis is placed on hadron-collider experiments that present a particularly challenging environment for event se- lection and data collection. However, the lectures also explain how T/DAQ systems have evolved over the years to meet new challenges. Some examples are given from early experience with LHC T/DAQ systems during the 2008 single-beam operations. 1 Introduction These lectures concentrate on experiments at high-energy particle colliders, especially the general- purpose experiments at the Large Hadron Collider (LHC) [1]. These experiments represent a very chal- lenging case that illustrates well the problems that have to be addressed in state-of-the-art high-energy physics (HEP) trigger and data-acquisition (T/DAQ) systems. This is also the area in which the author is working (on the trigger for the ATLAS experiment at LHC) and so is the example that he knows best. However, the lectures start with a more general discussion, building up to some examples from LEP [2] that had complementary challenges to those of the LHC. The LEP examples are a good reference point to see how HEP T/DAQ systems have evolved in the last few years. Students at this school come from various backgrounds — phenomenology, experimental data analysis in running experiments, and preparing for future experiments (including working on T/DAQ systems in some cases). These lectures try to strike a balance between making the presentation accessi- ble to all, and going into some details for those already familiar with T/DAQ systems. -
India-CMS Newsletter Member Institutes/ Universities of India-CMS
India-CMS Newsletter Member Institutes/ Universities of India-CMS Vol 1. No. 1, July 2015 1. Nuclear Physics Division (NPD) Bhabha Atomic Research Center (BARC) Mumbai http://www.barc.gov.in/ First volume produced at: 2. Indian Institute of Science Education and Research (IISER) Department of Physics Pune http://www.iiserpune.ac.in Panjab University Sector 14 Chandigarh - 160014 3. Indian Institute of Technology (IIT), Bhubaneswar Bhubaneswar http:// www.iitbbs.ac.in 4. Department of Physics Indian Institute of Technology (IIT), Bombay Mumbai http://www.iitb.ac.in/en/education/academic-divisions 5. Indian Institute of Technology (IIT), Madras Chennai https://www.iitm.ac.in 6. School of Physical Sciences National Institute of Science Education and Research (NISER), Edited and Compiled by: Bhubaneswar http://physics.niser.ac.in/ Manjit Kaur Department of Physics 7. Department of Physics Panjab University Panjab University Chandigarh Chandigarh http://physics.puchd.ac.in/ [email protected] 8. Division of High Energy Nuclear and Particle Physics Ajit Mohanty Saha Institute of Nuclear Physics (SINP) Director Kolkata http://www.saha.ac.in/web/henppd-home Saha Institute of Nuclear Physics (SINP) Kolkatta 9. Department of High Energy Physics [email protected] Tata Institute of Fundamental Research (TIFR), Mumbai http://www.tifr.res.in/ ~dhep/ Abhimanyu Chawla Department of Physics 10. Department of Physics & Astrophysics Panjab University University of Delhi Chandigarh Delhi http://www.du.ac.in/du/index.php?page=physics-astrophysics [email protected] 11. Visva Bharti Santiniketan, West Bengal 731204 http://www.visvabharati.ac.in/Address.html 1 2 Contents Message ........................................................................................................................................................ 3 Message ....................................................................................................................................................... -
Status of the Ctf3 Commissioning
Proceedings of EPAC 2002, Paris, France STATUS OF THE CTF3 COMMISSIONING R. Corsini, B. Dupuy, L. Rinolfi, P. Royer, F. Tecker, CERN, Geneva, Switzerland A. Ferrari∗, Uppsala University, Sweden Abstract In this paper, we describe the present status of the fa- cility as well as the results of the first beam measurements The Preliminary Phase of the new CLIC Test Facility performed during the commissioning [4, 5]. These results CTF3 consists of a low-charge demonstration of the elec- are compared to beam dynamics predictions [6]. Finally, tron bunch train combination process on which the CLIC the next steps towards the completion of the experiment drive beam generation scheme is based. The principle of are described. the combination relies on the injection of short electron bunches into an isochronous ring using RF deflecting cavi- ties. The commissioning of this facility started in Septem- 2 COMMISSIONING WITH BEAM ber 2001, with alternating periods of installation work and 2.1 The Front-End and the Linac beam studies. In this paper, we present the status of the facility, the first beam measurements and the next steps to- The new thermionic gun built by LAL (“Laboratoire wards the completion of the experiment. de l’Acc´el´erateur Lin´eaire d’Orsay”) was successfully in- stalled and commissioned [7]. This triode gun produces a train of up to seven pulses at a repetition rate of 50 Hz. The 1 INTRODUCTION pulse length can be varied between 2 ns and 10 ns FWHM and the pulses are spaced by 420 ns, corresponding to the The Compact Linear Collider (CLIC) [1] RF power revolution period of the ring, as required for the bunch fre- source scheme is based on the production of a 30 GHz quency multiplication process. -
John Ellis Sergerudaz
SLAC-PUB-3101 April 1983 (T/E) SEARCH FOR SUPERSYMMETRY IN TOPONIUM DECAYS* JOHN ELLIS Stanjord Linear Accelerator Center Stanford Uniueraity, Stanford, California 9@05 and SERGERUDAZ School of Physics and Astronomy University of Minnesota, Minneapolis, Minnesota 55455 ABSTRACT Although cosmology and unification suggest that the mass of the gluino is larger than about 14 GeV, in many theories of broken supersymmetry the photino 5, gluino S and one of the spin-zero partners i of the t quark can be lighter than mt. We calculate Z-T- the decay rates for toponium + 5 S, r 5 and t t and show that in many models they can be as large as, or larger than, the rate for toponium ---, e+e- decay. If it is kinematically accessible, the decay t --* t+q dominates the decays of toponium as well as those of naked top states. Submitted to Physics Letters B * Work supported by the Department of Energy, contracts DEAC03-76SF00515 and DEAC02-83ER40051. One obstacle to the experimental search [l] for supersymmetry (susy) is our the- oretical ignorance about the likely masses of supersymmetric particles. This means that we cannot be sure where susy will first appear, and must plan a broad-band search. The production and detection of supersymmetric particles in hadron-hadron collisions (21, lepton-hadron collisions [3,4] and e+e- annihilation [3,5,6] have been extensively discussed. In the case of e+e- annihilation, there have been discussions of the production of squarks and gluinos in the continuum and of gluinos in heavy quarkonium decays [3,5,6]. -
6.2 Transition Radiation
Contents I General introduction 9 1Preamble 11 2 Relevant publications 15 3 A first look at the formation length 21 4 Formation length 23 4.1Classicalformationlength..................... 24 4.1.1 A reduced wavelength distance from the electron to the photon ........................... 25 4.1.2 Ignorance of the exact location of emission . ....... 25 4.1.3 ‘Semi-bare’ electron . ................... 26 4.1.4 Field line picture of radiation . ............... 26 4.2Quantumformationlength..................... 28 II Interactions in amorphous targets 31 5 Bremsstrahlung 33 5.1Incoherentbremsstrahlung..................... 33 5.2Genericexperimentalsetup..................... 35 5.2.1 Detectors employed . ................... 35 5.3Expandedexperimentalsetup.................... 39 6 Landau-Pomeranchuk-Migdal (LPM) effect 47 6.1 Formation length and LPM effect.................. 48 6.2 Transition radiation . ....................... 52 6.3 Dielectric suppression - the Ter-Mikaelian effect.......... 54 6.4CERNLPMExperiment...................... 55 6.5Resultsanddiscussion....................... 55 3 4 CONTENTS 6.5.1 Determination of ELPM ................... 56 6.5.2 Suppression and possible compensation . ........ 59 7 Very thin targets 61 7.1Theory................................ 62 7.1.1 Multiple scattering dominated transition radiation . .... 62 7.2MSDTRExperiment........................ 63 7.3Results................................ 64 8 Ternovskii-Shul’ga-Fomin (TSF) effect 67 8.1Theory................................ 67 8.1.1 Logarithmic thickness dependence -
Sacred Rhetorical Invention in the String Theory Movement
University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Communication Studies Theses, Dissertations, and Student Research Communication Studies, Department of Spring 4-12-2011 Secular Salvation: Sacred Rhetorical Invention in the String Theory Movement Brent Yergensen University of Nebraska-Lincoln, [email protected] Follow this and additional works at: https://digitalcommons.unl.edu/commstuddiss Part of the Speech and Rhetorical Studies Commons Yergensen, Brent, "Secular Salvation: Sacred Rhetorical Invention in the String Theory Movement" (2011). Communication Studies Theses, Dissertations, and Student Research. 6. https://digitalcommons.unl.edu/commstuddiss/6 This Article is brought to you for free and open access by the Communication Studies, Department of at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Communication Studies Theses, Dissertations, and Student Research by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. SECULAR SALVATION: SACRED RHETORICAL INVENTION IN THE STRING THEORY MOVEMENT by Brent Yergensen A DISSERTATION Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Doctor of Philosophy Major: Communication Studies Under the Supervision of Dr. Ronald Lee Lincoln, Nebraska April, 2011 ii SECULAR SALVATION: SACRED RHETORICAL INVENTION IN THE STRING THEORY MOVEMENT Brent Yergensen, Ph.D. University of Nebraska, 2011 Advisor: Ronald Lee String theory is argued by its proponents to be the Theory of Everything. It achieves this status in physics because it provides unification for contradictory laws of physics, namely quantum mechanics and general relativity. While based on advanced theoretical mathematics, its public discourse is growing in prevalence and its rhetorical power is leading to a scientific revolution, even among the public. -
Hep-Ph/0609102
CERN-PH-TH/2006-175 September 2006 Physics Opportunities with Future Proton Accelerators at CERN A. Blondel a, L. Camilleri b, A. Ceccucci b, J. Ellis b , M. Lindroos b , M. Mangano b , G. Rolandi b a University of Geneva CH-1211 Geneva 4, SWITZERLAND b CERN, CH-1211 Geneva 23, SWITZERLAND Abstract We analyze the physics opportunities that would be made possible by upgrades of CERN’s proton accelerator complex. These include the new physics possible with luminosity or energy upgrades of the LHC, options for a possible future neutrino complex at CERN, and opportunities in other physics including rare kaon decays, other fixed-target experiments, nuclear physics and antiproton physics, among other possibilities. We stress the importance of inputs from initial LHC running and planned neutrino experiments, and summarize the principal detector R&D issues. 1 Introduction and summary In our previous report [1], we presented an initial survey of the physics opportunities that could be provided by possible developments and upgrades of the present CERN Proton Accelerator Complex [2,3]. These topics have subsequently been discussed by the CERN Council Strategy Group [4]. In this report, we amplify and update some physics points from our initial report and identify detector R&D priorities for the preferred experimental programme from 2010 onwards. We consider experimentation at the high-energy frontier to be the top priority in choosing a strategy for upgrading CERN's proton accelerator complex. This experimentation includes the upgrade to optimize the useful LHC luminosity integrated over the lifetime of the accelerator, through both a consolidation of the LHC injector chain and a possible luminosity upgrade project we term the SLHC. -
Mayda M. VELASCO Northwestern University, Dept. of Physics And
Mayda M. VELASCO Northwestern University, Dept. of Physics and Astronomy 2145 Sheridan Road, Evanston, IL 60208, USA Phone: Work: +1 847 467 7099 Cell: +1 847 571 3461 E-mail: [email protected] Last Updated: May 2016 Research Interest { High Energy Experimental Elementary Particle Physics: Work toward the understanding of fundamental interactions and its important role in: (a) solving the problem of CP violation in the Universe { Why is there more matter than anti- matter?; (b) explaning how mass is generated { Higgs mechanism and (c) finding the particle nature of Dark-Matter, if any... The required \new" physics phenomena is accessible at the Large Hadron Collider (LHC) at the European Organization for Nuclear Research (CERN). I am an active member of the Compact Muon Solenoid (CMS) collaboration already collect- ing data at the LHC, that led to the discovery of the Higgs boson or \God particle" in 2012. Education: • Ph.D. 1995: Northwestern University (NU) Experimental Particle Physics • 1995: Sicily, Italy ERICE: Spin Structure of Nucleon • 1994: Sorento, Italy CERN Summer School • B.S. 1988: University of Puerto Rico (UPR) Physics (Major) and Math (Minor) Rio Piedras Campus Fellowships and Honors: • 2015: NU, The Graduate School (TGS) Dean's Faculty Award for Diversity. • 2008-09: Paid leave of absence sponsored by US Department of Energy (DOE). • 2002-04: Sloan Research Fellow from Sloan Foundation. • 2002-03: Woodrow Wilson Fellow from Mellon Foundation. • 1999: CERN Achievement Award { Post-doctoral. • 1996-98: CERN Fellowship with Experimental Physics Division { Post-doctoral. • 1989-1995: Fermi National Accelerator Laboratory(FNAL)/URA Fellow { Doctoral.