Free Electron Lasers and High-Energy Electron Cooling

Total Page:16

File Type:pdf, Size:1020Kb

Free Electron Lasers and High-Energy Electron Cooling BROPK EN L LABORATORY NAT,lY BNL-79509-2007-CP Free Electron Lasers and High-Energy Electron Cooling Vladimir N. Litvinenko (BNL), Yaroslav S. Derbenev (TJNAF') Presented at the FEL-07(2ghInternational Free Electron Laser Conference) 'Budker INP, Novosibirsk, Russia August 26-3 1,2007 October 2007 Collider-Accelerator Department Brookhaven National Laboratory P.O. Box 5000 Upton, NY 11973-5000 www.bnl.gov Notice: This manuscript has been authored by employees of Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the US. Depamnent of Energy. The publisher by accepting the manuscript for publication acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world- wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. This preprint is intended for publication in a journal or proceedings. Since changes may be made before publication, it may not be cited or reproduced without the author's permission. DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, nor any of their contractors, subcontractors, or their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or any third party’s use or the results of such use of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof or its contractors or subcontractors. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof FREE ELECTRON LASERS AND HIGH-ENERGY ELECTRON COOLING* Vladimir N. Litvinenko, BNL, Upton, Long Island, NY, USA’ Yaroslav S. Derbenev, TJNAF, Newport News, VA, USA) Abstract The main figure of merit of any collider is its average Cooling intense high-energy hadron beams remains a luminosity, i.e., its average productivity for an appropriate major challenge in modern accelerator physics. branch of physics, Cooling hadron beams at top energy Synchrotron radiation of such beams is too feeble to may further this productivity. provide significant cooling: even in the Large Hadron For a round beam, typical for hadron colliders, the Collider (LHC) with 7 TeV protons, the longitudinal luminosity is given by a simple expression: damping time is about thirteen hours. Decrements of traditional electron cooling decrease rapidly as the high power of beam energy, and an effective electron cooling of protons or antiprotons at energies above 100 GeV where N,, Nz are the number of particles per bunch, f, is seems unlikely. Traditional stochastic cooling still cannot their collision frequency, p* is the transverse p-function catch up with the challenge of cooling high-intensity at the collision point, E is the transverse emittance of the bunched proton beams - to be effective, its bandwidth beam, u, is the bunch length, and h s 1 is a coefficient must be increased by about two orders-of-magnitude. accounting for the so-called hourglass effect [l]: Two techniques offering the potential to cool high- h(x) = -e”“erfc(l/x).?In- energy hadron beams are optical stochastic cooling (OSC) X and coherent electron cooling (CEC) - the latter is the The hourglass effect is caused by variations in the beam’s focus of this paper. In the early 1980s, CEC was size orz=P*c(l+ s2/Ip“’) along the length of the suggested as a possibility for using various instabilities in an electron beam to enhance its interaction with hadrons collision region, which is defined by the bunch-length, 0,. (Le,, cooling them). The capabilities of present-day Accordingly, for h A.75, p* should be limited to values accelerator technology, Energy Recovery Linacs (ERLs), /3*au,. Hence, longitudinal cooling of hadron beam may and high-gain Free-Electron Lasers (FELs), finally caught allow reduction of p* and increase the colliders’ up with the idea and provided the all necessary luminosity. ingredients for realizing such a process. The effect of transverse emittance cooling on the In this paper, we discuss the principles, and the main collider’s luminosity is less straightforward. For beams limitations of the CEC process based on a high-gain FEL with limited intensities, the luminosity (1) grows as the driven by an ERL. We also present, and summarize in transverse emittance decreases. But luminosity in many Table 1, some numerical examples of CEC for ions and oolliders is limited by the beam-beam effects, and hence, protons in RHIC and the LHC. a reduction of emittance can be either counterproductive or luminosity-neutral. In this case, the role of transverse INTRODUCTION cooling is reduced to one of counteracting intra-beam scattering orland cooling large amplitudes of oscillation to In contrast with electron- and positron-beams, hadron lower the detector’s backgrounds. beams in storage rings (colliders) do not have strong loss The presence of strong damping in electron-positron mechanism (such as synchrotron radiation for leptons) colliders allows the use of significantly higher bunch and, therefore, do not have a natural damping mechanism intensities compared with hadron beams of the same to reduce their energy spreads and emittances. energy: the beam-beam tune shift can be about factor of There are several reasons why cooling high-energy four larger in the best lepton colliders than in best hadron hadron beams, mostly at the top energy range of a colliders. The accelerator community discussed the collider, is strongly desirable. conjecture that effective (strong) cooling of hadron beams First, any increases in the longitudinal- and transverse- might increase luminosity in such colliders via increasing emittances of a hadron beam accumulated during multi- the allowable beam-beam tune-shift. We emphasize that stage acceleration from a source to the store energy this assertion, though worth mentioning, ~LXZ.V (collision) remain in the beam. Any instability causing the meculative and should not be accepted without serious growth of emittance (for example, that of the electron skepticism. cloud that is the limiting factor for most modem hadron The electron-hadron collider, eRHIC, however, is one colliders) may entail the need to discard accelerated type of collider where cooling the hadron beam offers beams and start the process again. In any case, present- dramatic advantages [2]. In eRHIC, polarized electrons day high-energy hadron colliders do not have control of accelerated in an ERL will collide with hadrons stored in beam emittances at the collision energy, and are forced to the RHIC’s storage ring. In this case, a reduction in the use beams as they are; this is not always the optimum transverse emittance of the hadron beam engenders a approach. proportional reduction of the electron beam’s intensity * Work nerfomd iinder rhe awnice%of the 1I.S Denartmen1 of Rnerev. while maintaining its ultimate luminosity constant 131. The idea of coherent electron cooling (CEC) [10,11] Reduction of the electron beam’s current has multiple encompasses various possibilities of using collective advantages: reducing the strain on the polarized electron instabilities in the electron beam to enhance the source, proportionally lowering synchrotron radiation (the effectiveness of the interaction between hadrons and main source of the detector’s background); and, offering electrons. In this paper, we focus on a specific case of the possibility of increasing the electron beam’s energy. using a high gain FEL (driven by an ERL) for CEC. CEC Plans are to use a non-zero crossing angle at the Large combines the advantages of electrostatic interaction with Hadron Collider (LHC) at CERN [41. In this case, the broad band of FEL-amplifiers: examples in this paper reducing the bunch’s length would directly contribute to span from tens of THz to hundreds of PHz. Such systems increasing the luminosity and eliminating the necessity of are naturally fit into a straight section of modern high- having a crab-crossing system [51. energy hadron colliders. The proposed CEC method has Hence, high-energy hadron cooling may play important some potential advantages compared with the concept of role in increasing the performance of high-energy hadron optical stochastic cooling [121: and lepton-hadron cofiiders, including RHIC and eRHIC a) it may not entail significant modifications to the at Brookhaven National Laboratory, BNL, the Tevatron at lattice of the hadron machine ; Fermilab, and the LHC at CERN. b) it uses electrostatic interaction instead of very Electron cooling proved to be very efficient method of inefficient radiation and interaction with TEM cooling intense hadron- and ion-beams at low and waves by protons in a wiggler; medium energies [6]. The electron cooler of 9 GeV c) it is not limited to few potential choices of laser antiprotons in the Fermilab recycler represents state-of- frequencies and their bandwidths in THz range. the-art technology [7]. Development of the ERL-based Similar to other coherent cooling techniques, the CEC’s, electron cooler at BNL promises effective cooling of gold cooling rate is limited by the cross-talk of neighboring ions with energies of 100 GeV per nucleon [8]. hadrons (and the short noise in the electron beam). Thus, Nevertheless, the effectiveness of electron cooling is the cooling rate is limited by an effective number of weaker for protons than it is for ions (it scales with Z’IA, particles in a coherent sample, which is inversely where Z is the change number of an ion and A its atomic proportional to the amplifier’s bandwidth.
Recommended publications
  • Optical Stochastic Cooling Experiment at the Fermilab Iota Ring* J
    FERMILAB-CONF-18-182-AD OPTICAL STOCHASTIC COOLING EXPERIMENT AT THE FERMILAB IOTA RING* J. D. Jarvis†, V. Lebedev, H. Piekarz, A. L. Romanov, J. Ruan, Fermi National Accelerator Laboratory, Batavia, IL 60510-5011, USA M. B. Andorf, P. Piot1, Northern Illinois University, Dekalb, IL 60115, USA 1also at Fermi National Accelerator Laboratory, Batavia, IL 60510-5011, USA Abstract Beam cooling enables an increase of peak and average luminosities and significantly expands the discovery po- tential of colliders; therefore, it is an indispensable com- ponent of any modern design. Optical Stochastic Cooling (OSC) is a high-bandwidth, beam-cooling technique that Figure 1: Simplified conceptual schematic of an optical will advance the present state-of-the-art, stochastic cool- stochastic cooling section. A wavepacket produced in the ing rate by more than three orders of magnitude. It is an pickup subsequently passes through transport optics and enabling technology for next-generation, discovery- an optical amplifier. In the kicker undulator, each particle science machines at the energy and intensity frontiers receives an energy kick proportional to its momentum including hadron and electron-ion colliders. This paper deviation. presents the status of our experimental effort to demon- strate OSC at the Integrable Optics Test Accelerator (IO- pass through a SC system. In practice, the spectral band- TA) ring, a testbed for advanced beam-physics concepts width, W, of the feedback system (pickup, amplifier, and technologies that is currently being commissioned at kicker) sets a Fourier-limited temporal response T~1/2W, Fermilab. Our recent efforts are centered on the develop- which is very large compared to the intra-particle spacing ment of an integrated design that is prepared for final and limits the achievable cooling rate.
    [Show full text]
  • Optical Stochastic Cooling V
    OPTICAL STOCHASTIC COOLING V. Lebedev1, Fermilab, Batavia, IL 60510, U.S.A. Abstract Intrabeam scattering and other diffusion mechanisms result in a growth of beam emittances and luminosity degradation in hadron colliders. In particular, at the end of Tevatron Run II when optimal collider operation was achieved only about 40% of antiprotons were burned in collisions to the store end and the rest were discarded. Taking into account a limited rate of antiproton production further growth of the integral luminosity was not possible without beam cooling. Similar problems limit the integral luminosity in the RHIC operating with protons. For both cases beam cooling is the only effective remedy to increase the luminosity integral. Unfortunately neither electron nor stochastic cooling can be effective at the beam energy and the bunch density required for modern hadron colliders. Even in the case of LHC where synchrotron radiation damping is already helpful for beam cooling its cooling rates are still insufficient to support an optimal operation of the collider. In this paper we consider principles and main limitations for the optical stochastic cooling (OSC) representing a promising technology capable to achieve required cooling rates. The OSC is based on the same principles as the normal microwave stochastic cooling but uses much smaller wave length resulting in a possibility of dense beam cooling. Introduction The stochastic cooling was suggested by Simon Van der Meer [1]. It was critically important technology for success of the first proton-antiproton collider [2]. Since then it has been successfully used in a number of machines for particle cooling and accumulation.
    [Show full text]
  • Proton-Antiproton Colliding Beams Coming Nearer Work Well Under Way for One of the Experimental Areas at the CERN Proton- Antiproton Collider
    Proton-antiproton colliding beams coming nearer Work well under way for one of the experimental areas at the CERN proton- antiproton collider. The apparatus for the UA1 experiment will be assembled in the cylindrical shaft seen in the picture, and then rolled into position in a second shaft, to be excavated around the SPS tunnel. (Photo CERN 104.2.80) On 1 6 June the CERN SPS will start its 'big shutdown', with no operation for almost a year while the machine and experiments are prepared for proton-antiproton colliding beams. Such a major sacrifice of prime research time has never been seen before and is as sure a pointer as any to the importance of the extension in CERN's research potential which the proton-antiproton collider will bring. This article recalls the major features of the CERN scheme, and of the project at Fermilab, and de­ scribes the preparations now under way or imminent at CERN for the experiments and for the machines. The CERN scheme Thefirst CERN plans, orchestrated particularly by Carlo Rubbia, emerged in 1976 following crucial advances in accelerator physics — the demonstration at Novosibirsk of Gersh Budker's idea of electron cooling, and at CERN of Simon van der Meer's proposal for stochastic cooling. These beam cooling techni­ ques enable intense beams of stable particles to be built up, and thus make it feasible to do physics with colliding beams of antiprotons. The system which is now under construction at CERN will take 1013 protons, at 26 GeV and concen­ trated in five bunches, every 2.4 s from the PS to yield 2.5 x 107 anti- protons at 3.5 GeV from a target for subsequent injection into the Anti- proton Accumulator ring (AA).
    [Show full text]
  • THE PROTON-ANTIPROTON COLLIDER Lecture Delivered at CERN on 25 November 1987 Lyndon Evans
    CERN 88-01 11 March 1988 ORGANISATION EUROPÉENNE POUR LA RECHERCHE NUCLÉAIRE CERN EUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH CERN ACCELERATOR SCHOOL Third John Adams Memorial Lecture THE PROTON-ANTIPROTON COLLIDER Lecture delivered at CERN on 25 November 1987 Lyndon Evans GENEVA 1988 ABSTRACT The subject of this lecture is the CERN Proton-Antiproton (pp) Collider, in which John Adams was intimately involved at the design, development, and construction stages. Its history is traced from the original proposal in 1966, to the first pp collisions in the Super Proton Synchrotron (SPS) in 1981, and to the present time with drastically improved performance. This project led to the discovery of the intermediate vector boson in 1983 and produced one of the most exciting and productive physics periods in CERN's history. RN —Service d'Information Scientifique-RD/757-3000-Mars 1988 iii CONTENTS Page 1. INTRODUCTION 1 2. BEAM COOLING l 3. HISTORICAL DEVELOPMENT OF THE pp COLLIDER CONCEPT 2 4. THE SPS AS A COLLIDER 4 4.1 Operation 4 4.2 Performance 5 5. IMPACT OF EARLIER CERN DEVELOPMENTS 5 6. PROPHETS OF DOOM 7 7. IMPACT ON THE WORLD SCENE 9 8. CONCLUDING REMARKS: THE FUTURE OF THE pp COLLIDER 9 REFERENCES 10 Plates 11 v 1. INTRODUCTION The subject of this lecture is the CERN Proton-Antiproton (pp) Collider and let me say straightaway that some of you might find that this talk is rather polarized towards the Super Proton Synchrotron (SPS). In fact, the pp project was a CERN-wide collaboration 'par excellence'. However, in addition to John Adams' close involvement with the SPS there is a natural tendency for me to remain within my own domain of competence.
    [Show full text]
  • Accelerator Terms (To Add to This List
    Accelerator Terms (to add to this list please submit your term and definition to [email protected]) • Accelerator Device used to produce high-energy beams of charged particles such as electrons, protons, or heavy ions for research in high -energy and nuclear physics, synchrotron radiation research, medical therapies, and some industrial applications. • Alternating gradient Focusing with quadrupoles of alternating polarities, also called strong focusing. • BALS Beijing Advanced Light Source. • Beam cooling 1) Making beams more focusable by reducing its phase space. Radiation, ionization, electron, stochastic, optical stochastic and laser Doppler are different ways to cool charged particle beams. 2) Increasing the phase space density of the beam. More specifically, it is a non-Hamiltonian process in which Liouville’s theorem is violated. Examples: stochastic cooling, electron cooling, laser Doppler cooling. • Beam coupling impedance The beam coupling impedance is defined as a ratio of the generalized voltage (or kick, etc) created by a given perturbation of beam current interacting with a vacuum chamber element, to the amplitude of this current perturbation. • Beam position monitor (BPM) This diagnostic is used to measure a beam’s transverse position within the beam pipe, usually consisting of 4 plates (2 oriented vertically, 2 horizontally) that measure the strength of the electric field produced by the beam. • Beam power The product of particle energy and beam current. A very important parameter to explore rare events which can open a window beyond the standard model. • BEPC II The upgrading of the Beijing Electron-Epsitron Collider. • Beta function A term that relates beam size to the emittance, 2 / • Betatron Oscillation The wavelength of the transverse oscillation of a beam, measured in meters.
    [Show full text]
  • Fermilab Recycler Stochastic Cooling For
    Fermi National Accelerator Laboratory f FFEERRMMIILLAABB RREECCYYCCLLEERR SSTTOOCCHHAASSTTIICC CCOOOOLLIINNGG FFOORR LLUUMMIINNOOSSIITTYY PPRROODDUUCCTTIIOONN DD.. BBrrooeemmmmeellssiieekk,, CC.. GGaattttuussoo FFeerrmmii NNaattiioonnaall AAcccceelleerraattoorr LLaabboorraattoorryy,, BBaattaavviiaa IILL,, UU..SS..AA.. ABSTRACT The Fermilab Recycler began regularly delivering antiprotons for Tevatron luminosity operations in 2005. Methods for tuning the Recycler stochastic cooling systems are presented. The unique conditions and resulting procedures for minimizing the longitudinal phase space density of the Recycler antiproton beam are outlined. IINNTTRROODDUUCCTITIOONN IBS Experiment Recycler ring Circumference C 3320 m Sympathetic IBS cooling has been demonstrated at the Recycler. The measurements were conducted with a bunched antiproton Momentum p 8.9 GeV/c 10 Slippage factor η -0.0086 beam of 25×10 particles which was initially cooled transversely to a very small emittance (< 2 π mm-mrad). The momentum spread was increased to above 4.5 MeV/c by increasing the amplitude of the rf voltage and thus compressing the beam. The figures Emittance (n, 95%) εn ~3-5 µm below show the measured transverse emittance and longitudinal rms momentum spread evolutions. Also shown is the IBS model. Average β-function β 30 m ave The only adjustable parameter in this model is the vacuum-related emittance growth rate. Bunched beam stochastic cooling at the Recycler is being used to support Tevatron Collider operations. Experiments have shown that for fixed bunch lengths and stochastic cooling system gain, the asymptotic momentum spread is approximately the same. 5 4.55 m 4 u , h t w o r g ) 4.5 y k p kMp % 5 3 9 , t 0.85 MeV n jj ( e c dp jj n a 4.45 t t i m E 2 4.4 1 0 0.5 1 1.5 2 2.5 4.35 Measured longitudinal bunch distributions and RF waveforms for both barrier and parabolic buckets.
    [Show full text]
  • Optical Stochastic Cooling Experiment at the Fermilab Iota Ring* J
    FERMILAB-CONF-18-182-AD OPTICAL STOCHASTIC COOLING EXPERIMENT AT THE FERMILAB IOTA RING* J. D. Jarvis†, V. Lebedev, H. Piekarz, A. L. Romanov, J. Ruan, Fermi National Accelerator Laboratory, Batavia, IL 60510-5011, USA M. B. Andorf, P. Piot1, Northern Illinois University, Dekalb, IL 60115, USA 1also at Fermi National Accelerator Laboratory, Batavia, IL 60510-5011, USA Abstract Beam cooling enables an increase of peak and average luminosities and significantly expands the discovery po- tential of colliders; therefore, it is an indispensable com- ponent of any modern design. Optical Stochastic Cooling (OSC) is a high-bandwidth, beam-cooling technique that Figure 1: Simplified conceptual schematic of an optical will advance the present state-of-the-art, stochastic cool- stochastic cooling section. A wavepacket produced in the ing rate by more than three orders of magnitude. It is an pickup subsequently passes through transport optics and enabling technology for next-generation, discovery- an optical amplifier. In the kicker undulator, each particle science machines at the energy and intensity frontiers receives an energy kick proportional to its momentum including hadron and electron-ion colliders. This paper deviation. presents the status of our experimental effort to demon- strate OSC at the Integrable Optics Test Accelerator (IO- pass through a SC system. In practice, the spectral band- TA) ring, a testbed for advanced beam-physics concepts width, W, of the feedback system (pickup, amplifier, and technologies that is currently being commissioned at kicker) sets a Fourier-limited temporal response T~1/2W, Fermilab. Our recent efforts are centered on the develop- which is very large compared to the intra-particle spacing ment of an integrated design that is prepared for final and limits the achievable cooling rate.
    [Show full text]
  • Beam Cooling
    Beam Cooling M. Steck, GSI, Darmstadt CAS, Warsaw, 27 September – 9 October, 2015 Beam Cooling longitudinal (momentum) cooling injection into the storage ring transverse cooling time Xe54+ 50 MeV/u p/p Xe54+ cooling off 15 MeV/u heating (spread) and cooling: energy loss (shift) good energy definition time small beam size highest precision with internal gas cooling on target operation M. Steck (GSI) CAS 2015, Warsaw Beam Cooling Introduction 1. Electron Cooling 2. Ionization Cooling 3. Laser Cooling 4. Stochastic Cooling M. Steck (GSI) CAS 2015, Warsaw Beam Cooling Beam cooling is synonymous for a reduction of beam temperature. Temperature is equivalent to terms as phase space volume, emittance and momentum spread. Beam Cooling processes are not following Liouville‘s Theorem: `in a system where the particle motion is controlled by external conservative forces the phase space density is conserved´ (This neglects interactions between beam particles.) Beam cooling techniques are non-Liouvillean processes which violate the assumption of a conservative force. e.g. interaction of the beam particles with other particles (electrons, photons, matter) M. Steck (GSI) CAS 2015, Warsaw Cooling Force Generic (simplest case of a) cooling force: vx,y,s velocity in the rest frame of the beam non conservative, cannot be described by a Hamiltonian For a 2D subspace distribution function cooling (damping) rate in a circular accelerator: Transverse (emittance) cooling Longitudinal (momentum spread) cooling M. Steck (GSI) CAS 2015, Warsaw Beam Temperature Where does the beam temperature originate from? The beam particles are generated in a ‘hot’ source at rest (source) at low energy at high energy In a standard accelerator the beam temperature is not reduced (thermal motion is superimposed the average motion after acceleration) but: many processes can heat up the beam e.g.
    [Show full text]
  • Beam Cooling
    BEAM COOLING D.Möhl CERN, Geneva, Switzerland. Abstract To date, four main methods to increase the phase-space density of + - circulating beams in storage rings are operational: cooling of e e -beams by synchrotron radiation, stochastic cooling of (anti-)protons and ions by a feedback system, cooling of protons and ions by electrons, and cooling of special ions by laser light. A fifth method, ionisation cooling of muons, is under intense development. Each of these techniques is covered in detail in previous accelerator school proceedings and other tutorial articles [1]. The present paper is the write-up of a one-hour lecture at the CERN Accelerator School as well as of an opening talk at a workshop (‘Phase- Space Cooling and Related Topics’, Bad Honnef, May 2001). The object is to introduce the different techniques in a common framework, to put them into perspective and to point to potential future developments. 1. INTRODUCTION Beam cooling aims at ‘the impossible’, namely at reducing --without loss of particles-- the (normalized) emittance of beams, thereby increasing their density also called ‘brightness’. To make this possible, one has to circumvent Liouville’s theorem [2]. For a long time this good old maxim was assumed to imply that in all beam handling operations the normalized phase space density can only decrease or at best stay constant. It took perseverance and insight, to overthrow this dogma. Beam cooling is thus a fascinating subject [3]. It attracts our curiosity as engineers and physicists for several good reasons: it was long thought to be impossible; it (still) is one of the most advanced techniques for beam handling; it has lead --and it will continue to lead-- to spectacular achievements in elementary particle research.
    [Show full text]
  • High Frequency Microwave Research for Advanced Accelerator Applications
    High Frequency Microwave Research for Advanced Accelerator Applications Richard Temkin Physics Department and Plasma Science and Fusion Center Massachusetts Institute of Technology DOE HEPAP AARD Sub-panel Meeting, Fermilab, Feb. 17, 2006 In collaboration with: M. Shapiro; J. Sirigiri; R. Milner (MIT Bates); W. Barletta (USPAS) Research supported by DOE HEP Outline z Motivation z Recent Progress z Future Plans z Centers of Excellence z Conclusions Motivation: Why High Frequency Microwaves? High frequency microwaves can extend the energy reach of linear colliders z Advantages of High Frequency Microwaves: z Accelerator size is reduced. z Energy stored in the accelerator structure decreases with frequency ω. z Higher gradient possible z Gradient limit due to dark current capture increases with ω. z What is the ultimate limit? z High Luminosity requires high average power sources z Highest frequency considered for the near future is 100 GHz. z Issues of High Frequency Microwaves: z Smaller structures hard to build z Microwave sources and components need development z Wakefields increase with frequency as ω3 Outline z Motivation z Recent Progress at MIT z MIT 17 GHz Accelerator Laboratory z High Gradient Research at 17 GHz z Photonic Bandgap Structure Research z Other Recent Progress z Future Plans z Centers of Excellence z Conclusions 17 GHz Accelerator Laboratory at MIT Modulator 700 kV, 780A RF 1 µs flattop Break- down / Klystron 25 MW RF @ 17.14 GHz Gun Test Stand 25 MeV Linac 0.5 m, 94 cells THz Novel High Gradient Smith- Structure / Photonic Purcell Bandgap Test Stand Expt. MIT 17 GHz 25 MeV Accelerator z Highest frequency stand-alone accelerator in the world.
    [Show full text]
  • Fifty Years of the CERN Proton Synchrotron: Volume 2
    CERN–2013–005 12 August 2013 ORGANISATION EUROPÉENNE POUR LA RECHERCHE NUCLÉAIRE CERN EUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH Fifty years of the CERN Proton Synchrotron Volume II Editors: S. Gilardoni D. Manglunki arXiv:1309.6923v1 [physics.acc-ph] 26 Sep 2013 GENEVA 2013 ISBN 978–92–9083–391–8 ISSN 0007–8328 DOI 10.5170/CERN–2013–005 Copyright c CERN, 2013 Creative Commons Attribution 3.0 Knowledge transfer is an integral part of CERN’s mission. CERN publishes this report Open Access under the Creative Commons Attribution 3.0 license (http://creativecommons.org/licenses/by/3.0/) in order to permit its wide dissemination and use. This monograph should be cited as: Fifty years of the CERN Proton Synchrotron, volume II edited by S. Gilardoni and D. Manglunki, CERN-2013-005 (CERN, Geneva, 2013), DOI: 10.5170/CERN–2013–005 Dedication The editors would like to express their gratitude to Dieter Möhl, who passed away during the preparatory phase of this volume. This report is dedicated to him and to all the colleagues who, like him, contributed in the past with their cleverness, ingenuity, dedication and passion to the design and development of the CERN accelerators. iii Abstract This report sums up in two volumes the first 50 years of operation of the CERN Proton Synchrotron. After an introduction on the genesis of the machine, and a description of its magnet and powering systems, the first volume focuses on some of the many innovations in accelerator physics and instrumentation that it has pioneered, such as transition crossing, RF gymnastics, extractions, phase space tomography, or transverse emittance measurement by wire scanners.
    [Show full text]
  • Use of an Electron Beam for Stochastic Cooling* Y
    USE OF AN ELECTRON BEAM FOR STOCHASTIC COOLING* Y. Derbenev, TJNAF, Newport News, VA 23606, U.S.A. Abstract cooling projects for hadron beams quests to search for Microwave instability of an electron beam can be used possible ways to enhance efficiency of existing cooling for a multiple increase in the collective response for the methods or invent new techniques. perturbation caused by a particle of a co-moving ion It was noted by earlier works [9], that potential of an beam, i.e. for enhancement of friction force in electron electron beam-based cooling techniques may not be cooling method. The low scale (hundreds GHz and higher exhausted by the classical electron cooling scheme. frequency range) space charge or FEL type instabilities Namely, the idea of coherent electron cooling (CEC) can be produced (depending on conditions) by introducing encompasses various possibilities of using collective an alternating magnetic fields along the electron beam instabilities in the electron beam to enhance the path. Beams’ optics and noise conditioning for obtaining a effectiveness of interaction between hadrons and maximal cooling effect and related limitations will be electrons. CEC combines the advantages of two existing discussed. The method promises to increase by a few methods, electron cooling (microscopic scale of orders of magnitude the cooling rate for heavy particle interaction between ion beam and cooling media, the beams with a large emittance for a wide energy range electron beam) and stochastic cooling (amplification of with respect to either electron and conventional stochastic media response to ions). It is based on use of a co- cooling.
    [Show full text]