COOL 2007 - List of Keywords (simulation)

A B C D E F G H I K L O P Q R S T U V

simulation

Paper	Title	Other Keywords	Page
MOM2I03	Progress of High-energy Electron Cooling for RHIC	electron, ion, luminosity, emittance	11
	A. V. Fedotov BNL, Upton, Long Island, New York
	Funding: Work supported by the U. S. Department of Energy. The fundamental questions about QCD which can be directly answered at Relativistic Heavy Ion Collider (RHIC) call for large integrated luminosities. The major goal of RHIC-II upgrade is to achieve 10 fold increase in luminosity of Au ions at the top energy of 100 GeV/n. A significant increase in luminosity for polarized protons is also expected, as well as for other ion species and for various collision energies. Such a boost in luminosity for RHIC-II is achievable with implementation of high-energy electron cooling. The design of the higher-energy cooler for RHIC recently adopted a non-magnetized approach which requires a low temperature electron beam. Such high-intensity high-brightness electron beams will be produced with superconducting Energy Recovery Linac (ERL). Detailed simulations of the electron cooling process and numerical simulations of the electron beam transport including the cooling section were performed. An intensive R&D of various elements of the design is presently underway. Here, we summarize progress in these electron cooling efforts.
	Slides

MOM2I04	Cooling Simulations with the BETACOOL Code	ion, electron, target, emittance	16
	A. O. Sidorin JINR, Dubna, Moscow Region
	BETACOOL program developed by JINR electron cooling group is a kit of algorithms based on common format of input and output files. General goal of the program is to simulate long term processes (in comparison with the ion revolution period) leading to variation of the ion distribution function in 6 dimensional phase space. The BETACOOL program includes three algorithms for beam dynamics simulation and takes into account the following processes: electron cooling, intrabeam scattering, ion scattering on residual gas atoms, interaction of the ion beam with internal target and some others.
	Slides

TUM2I04	Ionization Cooling	emittance, collider, scattering, factory	68
	R. P. Johnson Muons, Inc, Batavia
	Funding: Supported by DOE SBIR/STTR grants DE-FG02-04ER84016, 04ER86191, 05ER86252, and 05ER886253 All three components of a particle’s momentum are reduced as a particle passes through and ionizes some energy absorbing material. If the longitudinal momentum is regenerated by RF cavities, the angular divergence of the particle is reduced. This is the basic concept of ionization cooling. What can be done for a muon beam with this simple idea is almost amazing, especially considering that the muon lifetime is only 2.2 μs in its rest frame. In this lecture we will discuss the evolution and present status of this idea, where we are now ready to design muon colliders, neutrino factories, and intense muon beams with very effective cooling in all six phase space dimensions. The discussion will include the heating effects and absorber Z-dependence of multiple scattering, numerical simulation programs, the accuracy of scattering models, emittance exchange, helical cooling channels, parametric-resonance ionization cooling, reverse emittance exchange, and the ionization cooling demonstration experiments, MICE and MANX.
	Slides

TUM2I06	Cooling Scheme for a Muon Collider	collider, lattice, emittance, proton	77
	R. B. Palmer, J. S. Berg, R. C. Fernow, J. C. Gallardo, H. G. Kirk BNL, Upton, Long Island, New York Y. Alexahin, D. V. Neuffer Fermilab, Batavia, Illinois S. A. Kahn Muons, Inc, Batavia D. J. Summers UMiss, University, Mississippi
	Abstract text to be submitted by the author
	Slides

TUA1I02	Theoretical Study of Emittance Transfer	emittance, coupling, resonance, electron	82
	H. Okamoto Hiroshima University, Higashi-Hiroshima K. Kaneta HU/AdSM, Higashi-Hiroshima A. Sessler LBNL, Berkeley, California
	Funding: Work supported in part by the U. S. Department of Energy, Office of Basic Energy Sciences, under Contract No. DE-AC02-05CH11231. Liouville's theorem implies that the six-dimensional phase-space volume occupied by a charged-particle beam is an approximate invariant unless the beam is subjected to dissipative interactions (such as in cooling). Symplectic conditions, in a Hamiltonian system (once again, no dissipation), put constraints upon emittance transfer between the various degrees of freedom. [1] We can, however, even in non-dissipative Hamiltonian systems arrange for partial emittance transfers. This process results in phase space correlations and change in the emittance projections on to various phase planes; namely, the projected emittances in three degrees of freedom are controllable while the direction and amount of a possible emittance flow are not very flexible because of the symplectic nature of Hamiltonian system. In some applications, it is clearly advantageous to optimize the ratios of projected emittances despite the effect of correlations. Since the three emittances are not always equally important, we may consider reducing the emittance of one direction at the sacrifice of the other emittance(s). As a possible scheme to achieve such emittance control, we study a compact storage ring operating near resonance. The basic features of linear and nonlinear emittance flow are briefly discussed with numerical examples. A general discussion touching on some of these matters has been previously presented. [2] [1] E. D. Courant, Perspectives in Modern Physics, edit R. E. Marshak (1966).[2] H. Okamoto, K. Kaneta and A. M. Sessler, to be published in J. Phys. Soc. Jpn.
	Slides

TUA1C03	Necessary Condition for Beam Ordering	proton, electron, ion, scattering	87
	A. V. Smirnov, I. N. Meshkov, A. O. Sidorin JINR, Dubna, Moscow Region J. Dietrich FZJ, Jülich A. Noda, T. Shirai, H. Souda, H. Tongu Kyoto ICR, Uji, Kyoto K. Noda NIRS, Chiba-shi
	The very low momentum spread for small number of particle was reached on different storage rings. When the sudden reduction of the momentum spread ("phase transition") was observed during decreasing of the particle number it was interpreted as ordered state of ion beams. The most extensive study of ordered ion beams was done on storage rings ESR (GSI, Darmstadt) and CRYRING (MSL, Stockholm). Recently, for the first time, the ordered proton beam has been observed on S-LSR (Kyoto University). From analysis of the ESR experimental results we assumed that the ordered state can be observed if the dependence of momentum spread on the particle number can be approximated as ∆P/P ~ N^k for k < 0.3. In pioneering experiments at NAP-M (INP, Novosibirsk) and, in recent years, at COSY (FZJ, Juelich) the phase transition was not observed and the coefficient was found equal k > 0.5. This report presents the experimental investigations of low intensity proton beams on COSY and S-LSR which have the aim to formulate the necessary conditions for the achievement of the ordered state. The experimental studies on S-LSR and numerical simulations with the BETACOOL code were done for the dependence of the momentum spread and transverse emittances on particle number with different misalignments of the magnetic field at the cooler section. As result of both experimental and numerical studies one can conclude that the necessary condition for the phase transition appearance is k < 0.3.
	Slides

TUA1I04	High-Energy Colliding Crystals – A Theoretical Study	lattice, ion, collider, luminosity	91
	J. Wei BNL, Upton, Long Island, New York H. Okamoto Hiroshima University, Higashi-Hiroshima A. Sessler LBNL, Berkeley, California H. Sugimoto, Y. Yuri HU/AdSM, Higashi-Hiroshima
	*Funding: Work performed under the auspices of the U. S. Department of Energy. Recent theoretical investigations of beam crystallization mainly use computer modeling based on the method of molecular dynamics (MD) and analytical study based on phonon theory [1]. Topics of investigation include crystal stability in various accelerator lattices under different beam conditions, colliding crystalline beams [2], and crystalline beam formation in shear-free ring lattices with both magnets and electrodes [3]. In this paper, we review the above mentioned theoretical studies and, in particular, discuss the development of the phonon theory in a time-dependent Hamiltonian system representing a storage ring of AG focusing. Analytical study of crystalline beam stability in an AG-focusing ring was previously limited to the smooth approximation. In a typical ring, analytical results obtained under such approximation largely agrees with the results obtained with the molecular dynamics (MD) simulation method. However, as we explore ring lattices appropriate for beam crystallization at high energies (Lorentz factor gamma much higher than the betatron tunes) [2,4], this approximation fails. Here, we present a newly developed formalism to exactly predict the stability of a 1-dimensional crystalline beam in an AG focusing ring lattice. [1] X.-P. Li, et al, PR ST-AB, 9, 034201 (2006). [2] J. Wei, A. M. Sessler, EPAC, 862 (1998)[3] M. Ikegami, et al, PR ST-AB 7, 120101 (2004).[4] J. Wei, H. Okamoto, et al, EPAC 2006.**
	Slides

WEM2I05	Bunched Beam Stochastic Cooling Simulations and Comparison with Data	pick-up, emittance, kicker, ion	125
	M. Blaskiewicz, J. M. Brennan BNL, Upton, Long Island, New York
	Funding: Work performed under the auspices of the United States Department of Energy. With the experimental success of longitudinal, bunched beam stochastic cooling in RHIC it is natural to ask whether the system works as well as it might and whether upgrades or new systems are warranted. A computer code, very similar to those used for multi-particle coherent instability simulations, has been written and is being used to address these questions.

WEM2C06	Simulation of Cooling Mechanisms of Highly-charged Ions in the HITRAP Cooler Trap	ion, electron, space-charge, synchrotron	130
	G. Maero, F. Herfurth, O. K. Kester, H. J. Kluge, S. Koszudowski, W. Quint GSI, Darmstadt S. Schwarz NSCL, East Lansing, Michigan
	The use of heavy and highly-charged ions gives access to unprecedented investigations in the field of atomic physics. The HITRAP facility at GSI will be able to slow down and cool ion species up to bare uranium to the temperature of 4 K. The Cooler Trap, a confinement device for large numbers of particles, is designed to store and cool bunches of 10⁵ highly-charged ions. Electron cooling with 10¹⁰ simultaneously trapped electrons and successive resistive cooling lead to extraction in both pulsed and quasi-continuous mode with a duty cycle of 10 s. After an introduction to HITRAP and overview of the setup, the dynamics of the processes investigated via a Particle-In-Cell (PIC) code are shown, with emphasis on the peculiarities of our case, namely the space charge effects and the modelling of the cooling techniques.
	Slides

THM1I02	Electron Cooling Experiments at S-LSR	electron, ion, proton, heavy-ion	139
	T. Shirai, S. Fujimoto, M. Ikegami, A. Noda, H. Souda, M. Tanabe, H. Tongu Kyoto ICR, Uji, Kyoto H. Fadil, M. Grieser MPI-K, Heidelberg T. Fujimoto, S. I. Iwata, S. Shibuya AEC, Chiba I. N. Meshkov, A. V. Smirnov, E. Syresin JINR, Dubna, Moscow Region K. Noda NIRS, Chiba-shi
	Funding: The present work has been supported from Advanced Compact Accelerator Development Project by MEXT of Japan and 21 COE at Kyoto University-Center for Diversity and Universality in Physics. The ion storage ring, S-LSR in Kyoto University has an electron beam cooler and a laser cooling system. The electron cooler for S-LSR was designed to maximize the cooling length in the limited drift space of the ring. The effective cooling length is 0.44 m, while the total length of the cooler is 1.8 m. The commissioning of the electron cooling was started from October 2005. The 7 MeV proton beam from the linac was used and the first cooling was observed on October 31. The momentum spread became 2×10^-4 and the beam diameter was 1.2 mm with the particle number of 2×10⁸ and the electron current of 60 mA. The various experiments have been carried out using the electron cooling at S-LSR. The one-dimensional ordering of protons is one of the important subjects. The momentum spread and the beam size were observed while reducing the particle number. They were measured by the Schottky noise spectrum and the scraper. The particle number was measured by the ionization residual gas monitor. Abrupt jumps in the momentum spread and the Schottky noise power were observed for protons at a particle number of around 2000. The beam temperature was 0.17 meV and 1 meV in the longitudinal and transverse directions at the transition particle number, respectively. The normalized transition temperature of protons is close to those of heavy ions at ESR. The lowest momentum spread below the transition was 1.4×10^-6, which corresponded to the longitudinal beam temperature of 0.026 meV (0.3 K). It is close to the longitudinal electron temperature. The transverse temperature of the proton beam was much below that of electrons (34 meV). It is the effect of the magnetized electron.

THM2I04	Progress with Tevatron Electron Lenses	electron, proton, antiproton, gun	144
	V. Kamerdzhiev, Y. Alexahin, G. F. Kuznetsov, V. D. Shiltsev, X. Zhang Fermilab, Batavia, Illinois
	Funding: Work supported by the U. S. Department of Energy under contract No. DE-AC02-07CH11359 The Tevatron Electron Lenses (TELs) were initially proposed for compensation of long-range and head-on beam-beam effects of the antiproton beam at 980 GeV. Recent advances in antiproton production and electron cooling led to a significant increase of antiproton beam brightness. It is now the proton beam that suffers most from the beam-beam effects. Discussed are the concept of Electron Lenses and commissioning of the second TEL in 2006-2007. The latest experimental results obtained during numerous studies with high energy proton beam are presented.
	Slides

THAP01	Electron Cooling Simulation for Arbitrary Distribution of Electrons	electron, ion, emittance, acceleration	159
	A. O. Sidorin, A. V. Smirnov JINR, Dubna, Moscow Region I. Ben-Zvi, A. V. Fedotov, D. Kayran BNL, Upton, Long Island, New York
	Typically, several approximations are being used in simulation of electron cooling process, for example, density distribution of electrons is calculated using an analytical expression and distribution in the velocity space is assumed to be Maxwellian in all degrees of freedom. However, in many applications, accurate description of the cooling process based on realistic distribution of electrons is very useful. This is especially true for a high-energy electron cooling system which requires bunched electron beam produced by an Energy Recovery Linac (ERL). Such systems are proposed, for instance, for RHIC and electron – ion collider. To address unique features of the RHIC-II cooler, new algorithms were introduced in BETACOOL code which allow us to take into account local properties of electron distribution as well as calculate friction force for an arbitrary velocity distribution. Here, we describe these new numerical models. Results based on these numerical models are compared with typical approximations using electron distribution produced by simulations of electron bunch through ERL of RHIC-II cooler.

THAP02	Implementation of Synchrotron Motion in Barrier Buckets in the BETACOOL Program	ion, synchrotron, electron, target	163
	A. V. Smirnov, A. O. Sidorin, G. V. Trubnikov JINR, Dubna, Moscow Region O. Boine-Frankenheim GSI, Darmstadt
	In the case of the internal pellet target the electron cooling and the stochastic cooling systems cannot compensate the mean energy losses of the ion beam. In bunched ion beams the space charge limit is reduced and the influence of intrabeam scattering is enhanced, which causes a decrease of the luminosity in comparison with a coasting beam. To resolve these problems barrier buckets are proposed for experiments with the pellet target. In the barrier bucket the long ion bunch fills nearly the whole circumference of the storage ring and a rf pulse is applied at the head and at the tail of the bunch. The general goal of the BETACOOL program is to simulate long term processes (in comparison with the ion revolution period) leading to the variation of the ion distribution function in six dimensional phase space. The investigation of the beam dynamics for arbitrary distribution functions is performed using multi particle simulation in the frame of the Model Beam algorithm. In this algorithm the ion beam is represented by an array of macro particles. The heating and cooling processes involved in the simulations lead to a change of the particle momentum components and particle number, which are calculated each time step. The barrier bucket model was developed in the Model Beam algorithm of the BETACOOL program. The trajectory of each model particle is solved analytically for a given barrier bucket voltage amplitude. An invariant of motion is calculated from the current position of the model particle and from the barrier bucket voltage amplitude. Then the phase of the invariant is calculated in accordance with the integration step and the particle gets a new coordinates. The heating and cooling effects are applied in usual procedure of the Model Beam algorithm. First simulation results for the FAIR storage rings are presented.

THAP08	Electron Cooling in the Recycler Cooler	antiproton, electron, emittance, cathode	175
	A. V. Shemyakin, L. R. Prost Fermilab, Batavia, Illinois A. V. Fedotov BNL, Upton, Long Island, New York A. O. Sidorin JINR, Dubna, Moscow Region
	Funding: FNAL is operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy. A 0.1-0.5 A, 4.3 MeV DC electron beam provides cooling of 8 GeV antiprotons in Fermilab's Recycler storage ring. Properties of electron cooling have been characterized in measurements of the drag force, cooling rates, and equilibrium distributions. The paper will report experimental results and compare them with modeling by BETACOOL code.

THAP13	Recent Developments for the HESR Stochastic Cooling System	pick-up, impedance, coupling, kicker	191
	R. Stassen, P. B. Brittner, R. Greven, H. Singer, H. Stockhorst FZJ, Jülich L. Thorndahl CERN, Geneva
	Two cooling systems will be installed in the High-Energy Storage Ring (HESR) of the future international Facility for Antiproton and Ion Research (FAIR) at the GSI in Darmstadt: an electron cooler (1.5-8 GeV/c) and a stochastic cooling system from 3.8 GeV/c up to the highest momentum of the HESR (15 GeV/c). Both cooler are mandatory for the operation of the HESR with the PANDA pellet target. The relative low aperture (89mm) of the HESR suggests fixed structures without a plunging system. An octagonal layout was chosen to increase the sensitivity of the electrodes. Two different types of electrodes were built and tested. We will report on the comparison of printed λ/4 loops and new broadband slot couplers.

THAP14	Pick-Up Electrode System for the CR Stochastic Cooling System	pick-up, impedance, cryogenics, dipole	194
	C. Peschke, F. Nolden GSI, Darmstadt
	The collector ring (CR) of the FAIR project will include a fast stochastic cooling system for exotic nuclei with a β of 0.83 and antiprotons with a β of 0.97. To reach a good signal to noise ratio of the pick-up even with a low number of particles, a cryogenic movable pick-up electrode system based on slotlines is under development. The sensitivity and noise properties of an electrode array has been calculated using field-simulation and equivalent circuits. For three-dimensional field measurements, an E-near-field probe moved by a computer controlled mapper has been used.
	Poster

THAP20	Internal Target Effects in the ESR Storage Ring with Cooling	target, electron, storage-ring, ion	210
	V. Gostishchev, C. Dimopoulou, A. Dolinskii, F. Nolden, M. Steck GSI, Darmstadt
	The accurate description of the internal target effects is important for the prediction of operation conditions which are required for the performance of experiments in the storage rings of the FAIR facility at GSI. A number of codes such as PTARGET, MOCAC, PETAG01 and BETACOOL have been developed to evaluate the beam dynamics in the storage ring, where an internal target in the combination with an electron cooling is applied. The systematic benchmarking experiments were carried out at the ESR storage ring at GSI. The ‘zero’ dispersion mode (dispersion at target position is about 0 m) was applied to evaluate the influence of the dispersion function on the beam parameters when the internal target is ON. The influence of the internal target on the beam parameters is demonstrated. Comparison of the experimental results with the Bethe-Bloch formula describing the energy loss of the beam particles in the target as well as with simulations with the BETACOOL code will be given.

THAP21	Longitudinal Schottky Signals of Cold Systems with Low Number of Particles	ion, storage-ring, pick-up, electron	213
	R. W. Hasse GSI, Darmstadt
	Very cold systems of ions with sufficiently low number of particles arrange in an ordered string-like fashion. The determination of the longitudinal momentum spread and of the transverse temperature then is no longer possible by normal Schottky diagnosis. In this paper we simulate such systems in an infinitely long beam pipe with periodic boundary conditions under the influence of all long-range Coulomb interactions by Ewald summation. Then we derive the behaviour of the longitudinal Schottky signals for cold string-like systems as well as for the transition to warmer systems when the strings break, up to hot gas-like systems. Here effects from the finite number of particles, of higher harmonics and of temperature agree with those derived analytically in the limits of very low and very high temperatures.
	Poster

FRM2C05	Simulation Study of Beam Accumulation with Moving Barrier Buckets and Electron Cooling	electron, injection, ion, emittance	238
	T. Katayama, C. Dimopoulou, B. Franzke, M. Steck GSI, Darmstadt T. Kikuchi Utsunomiya University, Utsunomiya D. Möhl CERN, Geneva
	An effective ion beam accumulation method in NESR at FAIR project, is investigated with numerical way. The princile of accumulation method is as follows: Ion beam bunch from the collector ring or synchrotron is injected in the longitudinal gap space prepared by moving barrier voltage in NESR. Injected beam becomes instantly coasting beam after switching off the barrier voltage and is migrated with the previously stacked beam. After the momentum spread is well cooled by electron cooling, the barrier voltage is switched on and moved to prepare the empty gap space for the next injection. This process is repeated say 20 times to attain the required intensity. We have investigated this stacking process numerically, including the Intra Beam Scattering effect which might limit the stacking current in the ring. Detailed simulated results will be presented for the NESR case as well as the ESR experimental parameters.
	Slides

FRM2C06	Electron Cooling Simulations for Low-energy RHIC Operation	electron, ion, emittance, luminosity	243
	A. V. Fedotov, I. Ben-Zvi, X. Chang, D. Kayran, T. Satogata BNL, Upton, Long Island, New York
	Funding: Work supported by the U. S. Department of Energy Recently, a strong interest emerged in running RHIC at low energies in the range of 2.5-25 GeV/n total energy of a single beam. Providing collisions in this energy range, which in RHIC case is termed “low-energy” operation, will help to answer one of the key questions in the field of QCD about existence and location of critical point on the QCD phase diagram. Applying electron cooling directly at these low energies in RHIC would result in dramatic luminosity increase, small vertex distribution and long stores. On the other hand, even without direct cooling in RHIC at these energies, significant luminosity gain can be achieved by decreasing the longitudinal emittance of the ion beam before its injection into RHIC from the AGS. This will provide good RF capture efficiency in RHIC. Such an improvement in longitudinal emittance of the ion beam can be provided at by a simple electron cooling system at injection energy of AGS. Simulations of electron cooling both for direct cooling at low-energies in RHIC and for pre-cooling in AGS were performed, and are summarized in this report.
	Slides