COOL 2007 - Classification:Stochastic Cooling/

Stochastic Cooling

Paper	Title	Page
MOA1I01	Bunched Beam Stochastic Cooling at RHIC	25
	J. M. Brennan, M. Blaskiewicz BNL, Upton, Long Island, New York
	Stochastic cooling of ions in RHIC has been implemtneted to counteract Intra-Beam Scattering and prevent debunching during stores for luminosity production. The two main challenges in cooling bunched beam at 100 GeV/n are the coherent components in the Schottky spectra and producing the high voltage for the kicker in the 5 - 8 GHz band required for optimal cooling. The technical solutions to these challenges are described. Results of cooling proton beam in a test run and cooling gold ions in the FY07 production run are presented.
	Slides
MOA1C02	Stochastic Cooling for the HESR at FAIR	30
	H. Stockhorst, R. Maier, D. Prasuhn, R. Stassen FZJ, Jülich T. Katayama CNS, Saitama L. Thorndahl CERN, Geneva
	The High-Energy Storage Ring (HESR) of the future International Facility for Antiproton and Ion Research (FAIR) at the GSI in Darmstadt is planned as an anti-proton cooler ring in the momentum range from 1.5 to 15 GeV/c. An important and challenging feature of the new facility is the combination of phase space cooled beams with internal targets. The required beam parameters and intensities are prepared in two operation modes: the high luminosity mode with beam intensities up to 10¹¹ and the high resolution mode with 10¹⁰ anti-protons cooled down to a relative momentum spread of only a few 10^-5. In addition to electron cooling transverse and longitudinal stochastic cooling are envisaged to accomplish these goals. A detailed numerical and analytical approach to the Fokker- Planck equation for momentum cooling including an internal target has been carried out to demonstrate the stochastic cooling capability. Cooling model predictions are compared with the stochastic cooling performance of the operational cooling system in the cooler synchrotron COSY.
	Slides
MOA1C03	Stochastic Cooling for the FAIR Project	35
	F. Nolden, A. Dolinskii, C. Peschke GSI, Darmstadt
	Stochastic cooling is used in the framework of the FAIR project at GSI for the first stage of phase space compression for both rare isotope and antiproton rings. The collector ring CR serves for the precooling of rare isotope and antiproton beams. Stochastic accumulation will be used for the preparation of high intensity beams for experiments in the HESR or for the low-energy FLAIR facility. The technical and beam parameters of these systems are presented. Stochastic cooling in the HESR is treated in a different contribution.
	Slides
TUA2C05	Introduction to the Session on Lattice Optimization for Stochastic Cooling	96
	D. Möhl CERN, Geneva
	Lattices that circumvent the ‘mixing dilemma’ for stochastic cooling have repeatedly been considered but were not adopted in the original design of existing cooling rings. Recently new interest has arisen to modify existing machines and to design future ‘optimum mixing rings’. This talk is meant to summarize the pros and cons with the aim to introduce the discussion.
	Slides
TUA2C09	Lattice Optimization for the Stochastic Cooling in the Accumulator Ring at Fermilab	110
	V. P. Nagaslaev, V. A. Lebedev, S. J. Werkema Fermilab, Batavia, Illinois
	New efforts are under way at Fermilab to increase the rate of the antiproton production. This program includes the machine optics optimization in order to improve mixing and help stochastic cooling. The new lattice has been implemented in May of this year. Results will be discussed, as well as some aspects of model development and lattice measurements.
	Slides
WEM1C02	Optical Stochastic Cooling Experiment at the MIT-Bates South Hall Ring	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)
	Slides
WEM2I05	Bunched Beam Stochastic Cooling Simulations and Comparison with Data	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.
THM2I05	Use of an Electron Beam for Stochastic Cooling*	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**
	Slides
THAP13	Recent Developments for the HESR Stochastic Cooling System	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	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
THAP15	Beam Based Measurements for Stochastic Cooling Systems at Fermilab	198
	V. A. Lebedev, R. J. Pasquinelli, S. J. Werkema Fermilab, Batavia, Illinois
	Maximizing performance of stochastic cooling would not be possible without beam based measurements. In this paper we discuss experience with beam based measurements of Antiproton source stochastic cooling; and how the measurement results are used in building of the cooling system model. Work supported by the Fermi Research Alliance, under contract DE-AC02-76CH03000 with the U. S. Dept. of Energy.
	Poster
THAP16	New Equalizers for Antiproton Stochastic Cooling at Fermilab	202
	V. A. Lebedev, R. J. Pasquinelli, D. Sun Fermilab, Batavia, Illinois
	To maximize performance of Antiproton source stochastic cooling we developed and built equalizers correcting both phase and amplitude of the system gain. Design requirements have been based on the beam measurements of the system gain. Paper presents principles of the design and details of engineering, manufacturing and tuning of the equalizers. Work supported by the Fermi Research Alliance, under contract DE-AC02-76CH03000 with the U. S. Dept. of Energy.
	Poster