kicker

Paper	Title	Other Keywords	Page
TUIOB02	Simulations of Stochastic Cooling of Antiprotons in the Collector Ring CR	pick-up, antiproton, betatron, emittance	58
	C. Dimopoulou, A. Dolinskii, T. Katayama, F. Nolden, C. Peschke, M. Steck GSI, Darmstadt D. Möhl, L. Thorndahl CERN, Geneva
	The Collector Ring at FAIR will be equipped with pertinent stochastic cooling systems in order to achieve fast cooling of the hot secondary beams, antiprotons and rare isotopes, thus profiting from the repetition rate of the SIS100 synchrotron. Detailed simulations of the system performance are needed for optimization as well as input for the users of the CR pre-coooled beams, e.g. HESR. We presently focus on the antiproton cooling in the band 1-2 GHz. After a short overview, results from Fokker-Planck simulations with the CERN code of the momentum cooling of antiprotons will be presented. The performance of the betatron cooling of antiprotons, which has to proceed simultaneously with the momentum cooling, was calculated separately by means of an analytical model. First results and their implications will be discussed, including an outlook to future simulation work.
	Slides
TUCOB01	Stochastic Cooling Project at the Experimental Storage Ring, CSRe at IMP	pick-up, simulation, vacuum, impedance	64
	J. X. Wu, J. W. Xia, Y. Zhang IMP, Lanzhou F. Caspers CERN, Geneva T. Katayama, F. Nolden GSI, Darmstadt
	Stochastic cooling at the experimental Cooler Storage Ring, CSRe at the Institute of Modern Physics (IMP) in China, will be used mainly for the experiments with radioactive fragment beams. Those RI beams arrive from the fragment separator with the emittance of 20-50 mm. mrad and the momentum spread Dp/p of ± 0.5~1.0 %. The equipped electron cooler is not able to cool down this hot beam within enough short period. Stochastic cooling is effective for these RI beams to reduce the emittance to less than 5 mm.mrad and Dp/p of 5·10-4 within 2-20 sec. After the stochastic pre-cooling, the electron cooling will further cool down the emittance and Dp/p within several seconds. The paper gives the design of the stochastic cooling system and the simulation results. The new developed forward traveling wave structure is presented as well as the measured results of test model.
	Slides
TUPS09	LEPTA Project: Towards Positrons	electron, positron, gun, focusing	111
	A. G. Kobets, E. V. Ahmanova, V. I. Lokhmatov, V. N. Malakhov, V. Pavlov, A. Yu. Rudakov, A. A. Sidorin, S. Yakovenko JINR, Dubna, Moscow Region M. K. Eseev NAFU, Arkhangelsk
	The Low Energy Positron Toroidal Accumulator (LEPTA) at JINR is under commissioning with circulating positron beam. The LEPTA facility is a small positron storage ring equipped with the electron cooling system and positron injector. The maximum positron energy is of 10 keV. The main goal of the project is generation of intensive flux of Positronium (Ps) atoms - the bound state of electron and positron, and setting up experiments on Ps in-flight. The report presents an advance in the project: up-grade of LEPTA ring magnetic system, status of the commissioning of positron transfer channel, the results of the electron cooling system tests, results of low energy positrons storage positron beam formation using Na22 radioactive positron source of radioactivity of 25 mCi.
TUPS15	The Stochastic Cooling System of HESR	pick-up, controls, impedance, accumulation	129
	R. Stassen, H. Stockhorst FZJ, Jülich T. Katayama GSI, Darmstadt L. Thorndahl CERN, Geneva
	The HESR is the high energy storage ring (1.5-15 GeV/c) for antiprotons at the FAIR facility (Facility for Antiprotons and Ion Research) in Darmstadt (GSI). Stochastic cooling in the HESR is necessary not only during the experiments to fulfill the beam requirements, but also during the accumulation due to the postponed RESR. Extensive simulations and prototype measurements have been carried out to optimize the HESR stochastic cooling system with the new slot-ring couplers. The system design is now in the final construction phase for the mechanical tank layout and all active RF-components. First results of the optical notch-filter with automated frequency control and the 4-6 GHz slot-ring couplers will be presented.
TUPS16	An Improved Forward Travelling Wave Structure Design for Stochastic Cooling at Experimental Cooler Storage Ring (CSRe) at the Institute of Modern Physics (IMP) in China	pick-up, impedance, simulation, storage-ring	132
	Y. Zhang, J. X. Wu IMP, Lanzhou F. Caspers, L. Thorndahl CERN, Geneva T. Katayama, F. Nolden GSI, Darmstadt
	An improved forward travelling wave (TW) structure as the pick-up/kicker is designed for the stochastic cooling to match the field wave’s (phase) velocity to that of the beam. The theoretical analysis is performed together with the simulations of the propagation characteristics. Using CST Microwave Studio (CST MWS), the simulated results, including phase velocity, characteristics impedance, and distributions of the longitudinal fields, are implemented and compared with the experimented results. The improved forward TW structure can be satisfied the requirements of stochastic cooling project at CSRe, which the phase velocity is closed to 0.70 (matching the desired beam energy of 400 MeV/u) and the characteristics impedance is 17 ohm.
TUPS19	Simulation Study of Barrier Bucket Accumulation with Stochastic Cooling at the GSI ESR	accumulation, electron, simulation, injection	136
	T. Katayama, F. Nolden, G. Schreiber, M. Steck GSI, Darmstadt T. Kikuchi Nagaoka University of Technology, Nagaoka, Niigata H. Stockhorst FZJ, Jülich
	The beam accumulation experiments with use of barrier bucket cavity and stochastic cooling was successfully performed at the ESR, GSI. The two methods of barrier voltage operation, moving barrier and fixed barrier cases were tried, and for some cases the electron cooling was additionally employed as well as the stochastic cooling. In the present paper, the beam accumulation process are simulated with particle tracking method where the cooling force (stochastic and electron cooling), the diffusion force and the barrier voltage force are included as well as the IBS diffusion effects. The simulation results are well in agreement with the experimental results.
TUPS20	Demonstration of Longitudinal Stacking in the ESR with Barrier Buckets and Stochastic Cooling	injection, antiproton, accumulation, synchrotron	140
	M. Steck, C. Dimopoulou, B. Franzke, O. E. Gorda, T. Katayama, F. Nolden, G. Schreiber GSI, Darmstadt I. N. Meshkov, A. O. Sidorin, G. V. Trubnikov JINR, Dubna, Moscow Region D. Möhl CERN, Geneva R. Stassen, H. Stockhorst FZJ, Jülich
	Fast longitudinal beam accumulation has been demonstrated in the ESR at GSI with an Ar18+ beam coming from the synchrotron SIS18 at 400 MeV/u. Continuous application of stochastic cooling in all three phase space directions, merges the stack with the new injected bunch. Longitudinal beam compression was achieved by using either short barrier bucket rf pulses or by successive injections onto the unstable fixed point of the rf bucket at h=1. This recent experiment in the ESR provides the proof of principle for the planned longitudinal stacking of pre-cooled antiprotons in the HESR, injected from the CR.