COOL 2007 - List of Keywords (electron)

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

electron

Paper	Title	Other Keywords	Page
MOM1I01	Status of the Recycler Ring	antiproton, emittance, collider, luminosity	1
	P. Derwent Fermilab, Batavia, Illinois
	Funding: US Department of Energy I will present the current operational status of the Fermilab Recycler Ring. Using a mix of stochastic and electron cooling, we prepare antiproton beams for the Fermilab Tevatron Collider program.
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MOM1I02	Status of the Antiproton Decelerator and of the ELENA Project at CERN	antiproton, emittance, optics, extraction	6
	P. Belochitskii CERN, Geneva
	The Antiproton Decelerator (AD) at CERN operates for physics since 2000. It delivers low energy antiprotons for production and study of antihydrogen, for atomic physics and for medical research. Two beam cooling systems, stochastic and electron, play key role in AD operation. They make transverse and longitudinal emittances small, which is obligatory condition for beam deceleration without losses, as well for physics. The machine performance is reviewed, along with plans for the future. Significant improvement of intensity and emittances of the beam delivered to the experiments could be achieved with the addition of a small ring suitable for further deceleration and cooling. The details of this new extra low energy antiproton ring (ELENA) and its status are presented.
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MOM2I03	Progress of High-energy Electron Cooling for RHIC	ion, luminosity, emittance, simulation	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.
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MOM2I04	Cooling Simulations with the BETACOOL Code	simulation, ion, 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.
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MOM2C05	Longitudinal Accumulation of Ion Beams in the ESR Supported by Electron Cooling	injection, pick-up, ion, accumulation	21
	C. Dimopoulou, B. Franzke, T. Katayama, G. Schreiber, M. Steck GSI, Darmstadt D. Möhl CERN, Geneva
	Recently,two longitudinal beam compression schemes have been successfully tested in the Experimental Storage Ring (ESR) at GSI with a beam of bare Ar ions at 65 MeV/u injected from the synchrotron SIS18. The first employs Barrier Bucket pulses, the second makes use of multiple injections around the unstable fixed point of a sinusoidal RF bucket at h=1. In both cases continuous application of electron cooling maintains the stack and merges it with the freshly injected beam. These experiments provide the proof of principle for the planned fast stacking of Rare Isotope Beams in the New Experimental Storage Ring (NESR) of the FAIR project.
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MOA2C05	Calculations on High-energy Electron Cooling in the HESR	target, antiproton, emittance, luminosity	44
	D. Reistad, B. Gålnander, K. Rathsman TSL, Uppsala A. O. Sidorin JINR, Dubna, Moscow Region
	Funding: This work is supported by Uppsala University through The Svedberg Laboratory and by the European Community under Contract Number 515873, DIRACsecondary-Beams The HESR will work in a high-resolution mode with 1·10¹⁰ stored antiprotons and a high-luminosity mode with 1·10¹¹ stored antiprotons. It will be equipped with both stochastic cooling and electron cooling systems. The main purpose of the electron-cooling system is to provide relative momentum spread in the antiproton beam of a few 1·10^-5 (90 %) during experiments with an internal hydrogen pellet target and with luminosity 2·10³¹ – 2·10³² cm^-2s^-1. The hydrogen pellet target is expected to produce a stream of frozen hydrogen pellets with diameter 30 μm, which move with 60 m/s and at a rate of 20,000 s^-1. The pellet stream is expected to have a diameter of 2–3 mm. Therefore, in order to avoid excessive fluctuations in the count rate, the antiproton beam size at the target must not be too small. This is solved by slightly tilting the electron beam with respect to the antiproton beam, thus making use of a so-called Hopf bifurcation. In order to get a high duty factor on another time scale, while not sacrificing momentum acceptance, a barrier-bucket rf. system will be employed. The electron-cooling system will initially be built for an antiproton energy range from 800 MeV to 9 GeV, but will be built so that its energy can be extended to the full energy of the HESR (14 GeV) at a later stage. The paper discusses the choice of parameters for the electron cooling system and presents simulations.
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MOA2I06	Electron Cooling Status and Characterization at Fermilab’s Recycler	antiproton, emittance, extraction, injection	49
	L. R. Prost, A. V. Burov, K. Carlson, A. V. Shemyakin, M. Sutherland, A. Warner Fermilab, Batavia, Illinois
	Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy FNAL’s electron cooler (4.3 MV, 0.1 A DC) has been integrated to the collider operation for almost two years, improving the storage and cooling capability of the Recycler ring (8 GeV antiprotons). In parallel, efforts are carried out to characterize the cooler and its cooling performance. This paper discusses various aspects of the cooler performance and operational functionality: high voltage stability of the accelerator (Pelletron), quality of the electron beam generated, operational procedures (off-axis cooling, electron beam energy measurements and calibration) and cooling properties (in the longitudinal and transverse directions). In particular, we show measurements of the friction force and cooling rates, which we compare to a non-magnetized model and conclude that the effective electron beam radius is smaller than expected.
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TUM1I01	Cooling Results from LEIR	ion, injection, gun, controls	55
	G. Tranquille CERN, Geneva
	The LEIR electron cooler has been successfully commissioned for the cooling and stacking of Pb⁵⁴⁺ ions in LEIR during 2006. The emphasis of the three short commissioning runs was to produce the so-called “early” beam needed for the first LHC ion run. In addition some time was spent investigating the difficulties that one might encounter in producing the nominal LHC ion beam. Cooling studies were also made whenever the machine operational mode made it possible, and we report on the preliminary results of the different measurements (cooling-down time, lifetime etc.) performed on the LEIR cooler. Our investigations also included a study of the influence of variable electron density distributions on the cooling performance.
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TUM1I02	Commissioning of Electron Cooling in CSRm	ion, accumulation, injection, acceleration	59
	X. D. Yang, D. Q. Gao, Y. He, G. H. Li, J. Li, Y. Liu, L. J. Mao, R. S. Mao, M. T. Song, J. W. Xia, G. Q. Xiao, J. C. Yang, X. T. Yang, Y. J. Yuan, W.-L. Zhan, W. Zhang, H. W. Zhao, T. C. Zhao, J. H. Zheng, Z. Z. Zhou IMP, Lanzhou V. V. Parkhomchuk BINP SB RAS, Novosibirsk
	A new generation cooler was commissioned in CSRm, ¹²C⁶⁺ beam with energy 7MeV/u was delivered by a small cyclotron SFC, then injected into CSRm by stripping mode, the average pulse particle number is about 6.8×10⁸ in one injection, with the help of electron cooling of partial hollow electron beam, 3×10⁹ particle were accumulated in the ring after 10 times injection in 10 seconds, and 2×10⁹ particle were accelerated to final energy 1GeV/u, the momentum spread and the lifetime of ion beam were measured roughly. The work point of ring was monitored during the process of acceleration. The close-orbit correction was done initially. The momentum cooling time was about 0.3sec. About 1.6×10¹⁰ particle was stored in the ring after longer time accumulation.
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TUM1I03	Comparison of Hollow Electron Devices and Electron Heating	ion, accumulation, emittance, antiproton	64
	V. V. Parkhomchuk BINP SB RAS, Novosibirsk
	The first results of the electron cooling with hollow electron beam are present. The electron coolers with varable electron beam profiles was commissioned at CERN and IMP (China). Accumulation of the ion beam was demonstrated.
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TUM2I05	MICE: The International Muon Ionization Cooling Experiment	target, coupling, emittance, factory	73
	A. P. Blondel, J. S. Graulich DPNC, Genève
	An international experiment to demonstrate muon ionization cooling is scheduled for beam at Rutherford Appleton Laboratory (RAL) in 2008. The experiment comprises one cell of the neutrino factory cooling channel, along with upstream and downstream detectors to identify individual muons and measure their initial and final 6D emittance to a precision of 0.1%. Magnetic design of the beam line and cooling channel are complete and portions are under construction. The experiment will be described, including cooling channel hardware designs, fabrication status, and running plans. Phase 1 of the experiment will prepare the beam line and provide detector systems, including time-of-flight, Cherenkov, scintillating-fiber trackers and their spectrometer solenoids, and an electromagnetic calorimeter. The Phase 2 system will add the cooling channel components, including liquid-hydrogen absorbers embedded in superconducting Focus Coil solenoids, 201-MHz normalconducting RF cavities, and their surrounding Coupling Coil solenoids. The MICE Collaboration goal is to complete the experiment by 2010.
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TUA1I02	Theoretical Study of Emittance Transfer	emittance, coupling, resonance, simulation	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.
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TUA1C03	Necessary Condition for Beam Ordering	proton, ion, scattering, simulation	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.
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WEM1C01	Status of the LEPTA Project	positron, septum, focusing, vacuum	113
	A. G. Kobets, E. V. Ahmanova, V. Bykovsky, I. I. Korotaev, V. I. Lokhmatov, V. N. Malakhov, I. N. Meshkov, V. Pavlov, R. Pivin, A. Yu. Rudakov, A. O. Sidorin, A. V. Smirnov, G. V. Trubnikov, S. Yakovenko JINR, Dubna, Moscow Region
	The Low Energy Positron Toroidal Accumulator (LEPTA) is under commissioning at JINR. The LEPTA facility is a small positron storage ring equipped with the electron cooling system. The project positron energy is of 4-10 keV. The main goal of the facility is to generate an intense flow of positronium atoms–the bound state of electron and positron. The focusing system of the LEPTA ring after solenoidal magnetic field remeasurement and correction has been tested with pulsed electron beam by elements. Some resonant effects of beam focusing have been observed. The experiments aiming to increase the life time of the circulating electron beam and test the electron cooling elector beam are in progress. Construction of the pulsed injector of the low energy positrons is close to the completion (CPS). The injector is based on ²²Na radioactive isotope and consists of the cryogenic positron source, the positron trap and the acceleration section. In the CPS positrons from the ²²Na tablet are moderated in the solid neon and transported into the trap, where they are accumulated during about 80 seconds. Then accumulated positrons are extracted by the pulsed electric field and accelerated in electrostatic field up to required energy (the injector as a whole is suspended at a positive potential that corresponds to required positron energy in the range of 4-10 keV). In injection pulse duration is about 300 nsec. The CPS has been tested at the low activity of isotope ²²Na tablet (100 MBq). The continuous positron beam with average energy of 1.2 eV and spectrum width of 1 eV has been obtained. The achieved moderation efficiency is about 1 %, that exceeds the level known from literature. The accumulation process in the positron trap was studied with electron flux. The life time of the electrons in the trap is 80 s and capture efficiency is about 0.4. The maximum number of the accumulated particles is 2·10⁺⁸ at the initial flux of 5·10⁺⁶ electrons per second.
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WEM1C02	Optical Stochastic Cooling Experiment at the MIT-Bates South Hall Ring	undulator, radiation, damping, lattice	117
	W. A. Franklin, K. A. Dow, J. P. Hays-Wehle, F. X. Kaertner, R. Milner, R. P. Redwine, A. M. Siddiqui, C. Tschalaer, E. Tsentalovich, D. Wang, F. Wang, J. van der Laan MIT, Middleton, Massachusetts M. Bai, M. Blaskiewicz, W. Fischer, B. Podobedov, V. Yakimenko BNL, Upton, Long Island, New York W. A. Barletta, A. Zholents, M. S. Zolotorev LBNL, Berkeley, California S.-Y. Lee IUCF, Bloomington, Indiana
	An experiment to demonstrate for the first time the principle of optical stochastic cooling* has been proposed using electrons at 300 MeV in the MIT-Bates South Hall Ring. The experiment will operate the Ring in a dedicated mode using a lattice tailored for transverse and longitudinal cooling. The experimental apparatus, including a magnetic chicane, undulator system, and ultrafast optical amplifier, has been designed to be compatible with existing technology. The experiment will study OSC physics to evaluate its prospects for future application at the high energy high brightness frontier and to develop deterministic diagnostics needed to achieve it. Details of the experiment design will be presented along with results from an initial beam feasibility study. *M. Zolotorev and A. Zholents, Phys. Rev. E 50, 3087 (1994)
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WEM1C03	Analysis of Resonances Induced by the SIS-18 Electron Cooler	resonance, space-charge, emittance, lattice	121
	S. Sorge, O. Boine-Frankenheim, G. Franchetti GSI, Darmstadt
	Due to the requirements concerning the quality of the particle beams in the FAIR project, i.e. a small momentum uncertainty together with high currents and, in the case of the storage rings, particle target interaction, there will be a strong need of electron cooling. On the other hand, an electron cooler acts as a non-linear optical element besides electron cooling. This may lead to the excitation of resonances possibly resulting in an increase of the emittance. The aim of this work is the calculation of resonances driven by the electron cooler in the Schwerionensynchrotron (SIS) 18 being a present device at GSI Darmstadt having an electron cooler. So, we get the opportunity to prove our results experimentally. For our calculations, we used a model system consisting of a rotation matrix representing the lattice and giving the according phase advance, and a non-linear transverse momentum kick representing the electron cooler in thin lens approximation. Proceeding in this way, we got only the resonances driven by the cooler. Furthermore, we used the MAD-X code to perform our calculations.
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WEM2C06	Simulation of Cooling Mechanisms of Highly-charged Ions in the HITRAP Cooler Trap	ion, simulation, 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.
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THM1I02	Electron Cooling Experiments at S-LSR	ion, proton, heavy-ion, simulation	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	proton, antiproton, gun, simulation	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.
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THM2I05	Use of an Electron Beam for Stochastic Cooling*	ion, plasma, hadron, collider	149
	Y. S. Derbenev Jefferson Lab, Newport News, Virginia
	*Funding: Authored by Jefferson Science Associate under U. S. DoE Contract No. DE-AC05-06OR23177 Microwave instability of an electron beam can be used for a multiple increase in the collective response for the perturbation caused by a particle of a co-moving ion beam, i.e. for enhancement of friction force in electron cooling method. The low scale (hundreds GHz and larger frequency range) space charge or FEL type instabilities can be produced (depending on conditions) by introducing an alternating magnetic fields along the electron beam path. Beams’ optics and noise conditioning for obtaining a maximal cooling effect and related limitations will be discussed. The method promises to increase by a few orders of magnitude the cooling rate for heavy particle beams with a large emittance for a wide energy range with respect to either electron and conventional stochastic cooling [1,2]. [1] Ya. S.Derbenev, Coherent Electron Cooling, UM HE 91-28, August 7, 1991[2] Ya. S.Derbenev, AIP Conf. Proc., No 253, p. 103. AIP 1992**
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THM2I06	Electron Beams as Stochastic 3D Kickers	kicker, ion, space-charge, gun	154
	V. B. Reva, A. V. Ivanov, V. V. Parkhomchuk BINP SB RAS, Novosibirsk
	This article describes an idea combining electron and stochastic cooling in one device. The amplified signal about displacements of the ion from pick-up electrode applied to the control electrode of an electron gun. Thus, a wave of the space charge in the electron beam is induced. This wave propagates with the electron beam to the cooling section. The space charge of the electron beam acts on the ion beam producing a kick. The effectiveness of the amplification can be improved with using a structure similar to a traveling-wave tube.

THAP01	Electron Cooling Simulation for Arbitrary Distribution of Electrons	ion, simulation, 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, simulation, 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.

THAP04	Optimization of the Magnet System for Low Energy Coolers	ion, dipole, gun, alignment	167
	A. V. Bubley, V. M. Panasyuk, V. V. Parkhomchuk, V. B. Reva BINP SB RAS, Novosibirsk
	Aspects of magnet design and field measurements are discussed in the view of low energy coolers construction. The paper describes some engineering solutions for the magnetic field improvement which provides appropriate conditions for the cooling process as well as electron and ion beams motion.

THAP06	Cooling in a Compound Bucket	antiproton, emittance, injection, diagnostics	171
	A. V. Shemyakin, C. M. Bhat, D. R. Broemmelsiek, A. V. Burov, M. Hu Fermilab, Batavia, Illinois
	Funding: FNAL is operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy. Presently antiprotons in Fermilab’s Recycler ring are stored between rectangular RF barriers and are cooled both by a stochastic cooling system in full duty-cycle mode and by a DC electron beam. Electron cooling creates correlation between longitudinal and transverse tails of the antiproton distribution because particles with large transverse actions are cooled much more slowly than the core ones. Introducing additional RF barriers of lower amplitude allows separating spatially (along the bunch) the core and the tail. In this scenario, stochastic cooling can be “gated” to the tail, i.e. applied with a high gain to the low-density region and turned off for the core portion of the beam. This significantly increases the cooling rate of the tail particles, while the temperature of the core is preserved by electron cooling. In this paper, we will describe the procedure and first experimental results in detail.

THAP08	Electron Cooling in the Recycler Cooler	antiproton, simulation, 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.

THAP09	Beam-based Field Alignment of the Cooling Solenoids for Fermilab’s Electron Cooler	dipole, antiproton, emittance, ground-motion	179
	L. R. Prost, A. V. Shemyakin Fermilab, Batavia, Illinois
	Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy The cooling section of FNAL’s electron cooler is composed of ten (10) 2 m-long, 105 G solenoids. When FNAL’s electron cooler (4.3 MeV, 0.1 A DC) was first install at the Recycler ring, the magnetic field of the cooling solenoid was carefully measured and compensated to attain the field quality necessary for effective cooling [V. Tupikov et al. COOL’05]. However, the tunnel ground motion deteriorates the field quality perceived by the beam over time. We have developed a technique which uses the cooling strength as an indication of the relative field quality and allowing us to re-align the longitudinal magnetic field in the successive solenoids of the cooling section assuming that the transverse component of the field in each solenoid has not varied.

THAP10	Status of Design Work Towards an Electron Cooler for HESR	antiproton, gun, diagnostics, vacuum	182
	B. Gålnander, T. Bergmark, O. Byström, S. Johnson, T. Johnson, T. Lofnes, G. Norman, T. Peterson, K. Rathsman, D. Reistad TSL, Uppsala H. Danared MSL, Stockholm
	Funding: Work supported by Uppsala University and by the European Union under FP6, Contract number 515873 - DIRAC Secondary Beams. The HESR-ring of the future FAIR-facility at GSI will include both electron cooling and stochastic cooling in order to achieve the demanding beam parameters required by the PANDA experiment. The high-energy electron cooler will cool antiprotons in the energy range 0.8 GeV to 8 GeV. The design is based on an electrostatic accelerator and shall not exclude a further upgrade to the full energy of HESR, 14.1 GeV. The beam is transported in a longitudinal magnetic field of 0.2 T and the requirement on the straightness of the magnetic field is as demanding as 10^-5 radians rms at the interaction section. Furthermore, care must be taken in order to achieve an electron beam with sufficiently small coherent cyclotron motion and envelope scalloping. This puts demanding requirements on the electron beam diagnostics as well as the magnetic field measuring equipment. Prototype tests of certain components for these tasks are being performed. The paper will discuss these tests and recent development in the design including the high-voltage tank, electron gun and collector, magnet system, electron beam diagnostics and the magnetic field measuring system.
	Poster

THAP12	Electron Cooling Design for ELIC - a High Luminosity Electron-Ion Collider *	ion, emittance, collider, kicker	187
	Y. S. Derbenev Jefferson Lab, Newport News, Virginia
	*Funding: Authored by Jefferson Science Associate under U. S. DoE Contract No. DE-AC05-06OR23177** An electron-ion collider (EIC) of center mass energy 90 GeV (9 GeV of electron beam x 225 GeV of proton beam) at luminosity level up to 10³⁵/cm²s is envisioned by high energy Nuclear Physics community as a facility adequate for studying of the fundamental properties of quark-gluon structure of nucleons and strong interactions. In response to this quest, a high luminosity ring-ring EIC design (ELIC) is developed at Jefferson Laboratory utilizing 12 GeV upgrade CEBAF accelerator as a full energy injector for electron storage ring . An inevitable component of EIC is high energy electron cooling (EC) for ion beam. The EC facility concept for ELIC is based on use of 30 mA, 125 MeV energy recovery linac (ERL) and 3A circulator-cooler ring (CCR) operated at 15 and 1500 MHz bunch repetition rate, respectively. To switch electron bunches between ERL and CCR, fast kickers of a frequency bandwidth above 2 GHz are designed. The design parameters of EC facility and preliminary results of study of electron beam transports, stability and emittance maintenance in ERL and CCR, together with scenario of forming and cooling of ion beam will be presented.

THAP19	Influences of Space Charge Effect during Ion Accumulation Using Moving Barrier Bucket Cooperated with Beam Cooling	ion, space-charge, injection, accumulation	206
	T. Kikuchi, S. Kawata Utsunomiya University, Utsunomiya T. Katayama GSI, Darmstadt
	Space charge effect is important role for stacking of antiprotons and ions in an accumulation ring. The Coulomb force displaces the beam orbits from the designed correct motion. The beam particles kicked out from the ring acceptance by the space charge force are lost. The space charge effect interfere the beam stacking, and the number of the accumulated beam decreases and the emittance is increased. The longitudinal ion storage method by using a moving barrier bucket system with a beam cooling can accumulate the large number of secondary generated beams. After the multicycle injections of the beam bunch, the stored particles are kicked by the space charge effect of the accumulated beam. Using numerical simulations, we employ the longitudinal particle tracking, which takes into account the barrier bucket voltage, the beam cooling and the space charge effect, for the study of the beam dynamics during the accumulation operations. T. Katayama, P. Beller, B. Franzke, I. Nesmiyan, F. Nolden, M. Steck, D. Mohl and T. Kikuchi, AIP Conference Proc. 821 (2005) 196.

THAP20	Internal Target Effects in the ESR Storage Ring with Cooling	target, simulation, 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, simulation	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

THAP22	Limitations of the Observation of Beam Ordering	ion, scattering, proton, emittance	217
	M. Steck, K. Beckert, P. Beller, C. Dimopoulou, F. Nolden GSI, Darmstadt
	One dimensional beam ordering of electron cooled low intensity heavy ion beams has been evidenced at the ESR storage ring as a discontinuous reduction of the momentum spread. Depending on the beam parameters, technical imperfections or any sources of heating can hamper or even prevent the observation of the momentum spread reduction. Limitations for the detection of the ordered beam will be described and illustrated by experimental results.

FRM1C02	Schottky Noise Signal and Momentum Spread for Laser-Cooled Beams at Relativistic Energies	laser, ion, bunching, storage-ring	226
	M. H. Bussmann, D. Habs LMU, München K. Beckert, P. Beller, B. Franzke, C. Kozhuharov, T. Kuehl, W. Noertershaeuser, F. Nolden, M. Steck GSI, Darmstadt Ch. Geppert, S. Karpuk Johannes Gutenberg University Mainz, Mainz C. Novotny Johannes Gutenberg University Mainz, Institut für Physik, Mainz S. Reinhardt MPI-K, Heidelberg G. Saathoff MPQ, Garching, Munich U. Schramm FZD, Dresden
	We report on the first laser cooling of a bunched beam of C³⁺ ions at the ESR (GSI) at a beam energy of E = 1.47 GeV. Combining laser cooling of the 2S1/2-2P3/2 transition with moderate bunching of the beam lead to a reduction of the longitudinal momentum spread by one order of magnitude if compared to pure electron cooling. If additional electron cooling was applied, thus increasing the coupling between the longitudinal and transverse degree of freedom, three-dimensional cold beams with a plasma parameter of unity could be attained. In a second measurement campaign, a combination of a sweeping-frequency and a fixed-frequency laser beam was succesfully implemented to increase the momentum acceptance of the narrow band laser force. This cooling scheme improved the match of acceptance of the laser force to the momentum spread of the beam and reduced heating due to intra beam scattering. In addition to the interesting beam dynamics observed at low momentum spreads of ∆p / p < 10^-6 precision spectroscopy of 2S1/2-2P1/2 and 2S1/2-2P3/2 transition was performed, both absolute and relative, at a precision challenging the best theoretical models available. The laser cooling schemes used at the ESR can be directly extended to the regime of ultra-relativistic ion energies at the new FAIR facility. There, it becomes possible to cool a large number of ion species using a single laser beam source, exploiting the relativistic Doppler shift of the laser frequency. Finally, the fluorescence photons emitted by these ultra-relativistic laser cooled ion beams can be directly used for precision X-ray spectroscopy of the cooling transitions. The resolution of such measurements would essentially be only limited by the resolution of the X-ray spectrometers available.
	Slides

FRM1C03	Electron Cooling with Photocathode Electron Beams Applied to Slow Ions at TSR and CSR	ion, target, cryogenics, cathode	230
	D. Orlov, H. Fadil, M. Grieser, J. Hoffmann, C. Krantz, O. Novotny, S. Novotny, A. Wolf MPI-K, Heidelberg
	We report electron cooling experiments using a cold electron beam of 55 eV produced by a cryogenic GaAs photocathode. With this device the beam of singly charged ions with a mass of 31 amu, specifically the CF⁺ ion, was cooled at an energy of 3 MeV (about 90 keV/u). Transverse cooling within 2-3 seconds to a very small equilibrium beam size was observed with an electron current of 0.3 mA (electron density of 3×10⁶ cm^-3, magnetic guiding field of 0.04 T). A beam size of about 0.1 mm was deduced from imaging of recombination products. The short cooling times are mostly due to the low electron temperatures of 1 meV in transverse and 0.03 meV in longitudinal direction. An electrostatic Cryogenic Storage Ring (CSR) for slow ion beams, including protons, highly charged ions, and polyatomic molecules is under construction at the MPI-K. It will apply electron cooling at electron beam energies from 165 eV for 300 keV protons down to a few eV for polyatomic singly charged ions. Photoelectrons from the GaAs photocathode with laboratory energy spreads of about 10 meV [1] will be applied for generating such electron beams. In a storage ring of this type, even low electron-ion merging magnetic fields of toroids cause a strong coupling between the horizontal and vertical motions of the stored ions, reducing the ring acceptance to an intolerably low level. We present a new merging scheme of eV-electrons with stored ions, based on the idea of bringing electrons to the ion axis in a uniform dipole magnetic field superimposed to a straight solenoid field. The new magnetic field arrangement strongly improves the ring acceptance and allows to use guiding magnetic fields as high as required to provide high-quality electron beams of eV-energies for the cooling of ions and for merged beam studies in storage rings. [1] D. A. Orlov et al., Appl. Phys. Letters 78, 2721 (2001)
	Slides

FRM2C04	Studies of Cooling and Deceleration at CRYRING for FLAIR	ion, antiproton, proton, space-charge	234
	H. Danared, A. Källberg, A. Simonsson MSL, Stockholm
	It is planned that the CRYRING synchrotron and storage ring will be moved to the future FAIR facility at GSI. There it will be used as the Low-energy Storage Ring LSR at FLAIR (Facility for Low-energy Antiproton and Ion Research). LSR will mainly be used for deceleration of antiprotons from 30 MeV down to minimum 300 keV and for deceleration of highly charged ions in the same range of magnetic rigidities. As a preparation for the transfer of CRYRING to FAIR, studies have been made in order to evaluate the performance of CRYRING for deceleration of particles relevant to FLAIR and to set specifications for beams in and out of LSR. Deceleration of protons have been studied by first accelerating the particles to 30 MeV, then decelerating back to 300 keV again. Up to 3·10⁸ protons have been decelerated in 1.8 s without intermediate cooling, and requirements on longitudinal and transverse emittances at 30 MeV for successful deceleration have been estimated. Other studies have included investigations of the space-charge limit for protons at 300 keV and measurements of transverse cooling times for H^- ions, simulating antiprotons. Also an attempt to compare longitudinal cooling forces between protons and H^- ions has been made.
	Slides

FRM2C05	Simulation Study of Beam Accumulation with Moving Barrier Buckets and Electron Cooling	injection, ion, emittance, simulation	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	ion, simulation, 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