IPAC2011 - Classification: 04 Hadron Accelerators / A11 Beam Cooling

Paper	Title	Page
THPS001	Experimental Studies of Beam Loss during Low Energy Operation with Electron Cooled Heavy Ions in the ESR	3424
	P.A. Görgen, O. Boine-Frankenheim TEMF, TU Darmstadt, Darmstadt, Germany S. Appel, C. Dimopoulou, S.A. Litvinov, M. Steck GSI, Darmstadt, Germany
	At the ESR at GSI electron cooled heavy ion beams are decelerated to 4 MeV/u and extracted for the HITRAP experiment. We will report about cooling equilibrium measurements at 4 and 30 MeV/u for Ar¹⁸⁺ coasting beams. We compare the equilibrium beam parameters with results from beam dynamics simulations using the BETACOOL code and an analytic model of reduced complexity. The time slot in which HITRAP accepts beam is 2μs long. For optimum efficiency the beam has to be bunched to this length before extraction. The obtained bunch profiles are compared to longitudinal beam dynamics simulations. Our measurements show that at both energies bunching leads to severe beam loss. The estimated transverse space charge tune shifts during the rf bunching indicate that resonance crossing might be responsible for the observed the beam loss. The influence of the tune shift will be further evaluated through resonance measurements.

THPS002	Progress of the 2 MeV Electron Cooler Development for COSY-Jülich/HESR	3427
	J. Dietrich, V. Kamerdzhiev FZJ, Jülich, Germany M.I. Bryzgunov, A.D. Goncharov, V.M. Panasyuk, V.V. Parkhomchuk, V.B. Reva, D.N. Skorobogatov BINP SB RAS, Novosibirsk, Russia
	The 2 MeV electron cooling system for COSY-Jülich was proposed to further boost the luminosity even in presence of strong heating effects of high-density internal targets. The project is funded since mid 2009. The design and construction of the cooler is accomplished in cooperation with the Budker Institute of Nuclear Physics in Novosibirsk, Russia. The 2 MeV cooler is also well suited in the start up phase of the High Energy Storage Ring (HESR) at FAIR in Darmstadt. It can be used for beam cooling at injection energy and is intended to test new features of the high energy electron cooler for HESR. The infrastructure necessary for the operation of the cooler in the COSY ring (radiation shielding, cabling, water cooling etc.) is established. The electron beam commissioning at BINP Novosibirsk is scheduled to start at May of 2011. First results are reported. Final commissioning at COSY-Jülich is planned for the end of 2011.

THPS003	Status of Stochastic Cooling Predictions at the HESR	3430
	H. Stockhorst, R. Maier, D. Prasuhn, R. Stassen FZJ, Jülich, Germany T. Katayama GSI, Darmstadt, Germany
	Detailed theoretical studies of stochastic cooling have been performed in order to fulfil the requirements for internal target experiments at the High-Energy Storage Ring (HESR) of the future Facility for Antiproton and Ion Research (FAIR) at the GSI in Darmstadt. A Fokker-Planck model and a particle tracking code utilizing the Filter and time-of-flight momentum cooling method have been developed for the 2 to 4 GHz cooling system. A barrier bucket cavity is included to compensate the mean energy loss due to the beam-target interaction. The code has been experimentally verified at the cooler synchrotron COSY. Since the RESR accumulator ring is postponed in the modularized start version of FAIR it is proposed to include the anti-proton accumulation function in the HESR downstream of the Collector Ring. Applying the radial stacking scheme well established at CERN and FNAL would result in a completely new and additional cooling system in the HESR. Instead a different way of beam accumulation has been selected that uses the already designed stochastic cooling system and the barrier bucket cavity of the HESR. Simulation results of the anti-proton accumulation in the HESR are presented.

THPS004	Beam Dynamics Simulation on Simultaneous use of Stochastic Cooling and Electron Cooling with Internal Target	3433
	T. Kikuchi, N. Harada, T. Sasaki, H. Tamukai Nagaoka University of Technology, Nagaoka, Niigata, Japan T. Katayama GSI, Darmstadt, Germany
	The small momentum spread of proton beam has to be realized and kept in the storage ring during the experiment with a dense internal target. The stochastic cooling alone does not compensate the momentum spread increases due to the scattering at the internal target. The dense proton beam in the six dimensional phase space includes intra-beam scattering as one of emittance growth mechanisms. The numerical simulation is carried out using Fokker-Planck equation solver, and the results on the simultaneous use of stochastic cooling and electron cooling at COSY are indicated.

THPS006	Present Status of Beam Cooling and Related Research at S-LSR	3436
	A. Noda, M. Nakao, H. Souda, H. Tongu Kyoto ICR, Uji, Kyoto, Japan T. Fujimoto, S.I. Iwata, S. Shibuya AEC, Chiba, Japan M. Grieser MPI-K, Heidelberg, Germany K. Ito, H. Okamoto HU/AdSM, Higashi-Hiroshima, Japan K. Jimbo Kyoto IAE, Kyoto, Japan K. Noda, T. Shirai NIRS, Chiba-shi, Japan
	Funding: Work supported by Advanced Compact Accelerator Development project of MEXT, and Global COE Program, "The Next Generation of Physics, Spun from Universality and Emergence" at Kyoto University. With the use of Ion Storage and Cooler Ring, S-LSR at ICR, Kyoto University, Mg ion beam with 40 keV has been laser cooled not only in the longitudinal direction but also in the horizontal direction by "Synchro-Betatron Coupling". Laser cooling is now tried to be extended to vertical direction with horizontal and vertical coupling with the use of a solenoid magnetic field. At S-LSR, an electron beam cooling is also applied for 7MeV proton beam, resulting an ordered state. Electron beam cooling is also applied for rf captured bunched beam and a short pulse proton beam with the duration of ~3 ns is fast extracted in order to enable beam irradiation. A beam course is now being constructed to irradiate bio-molecular cells vertically from the bottom through a thin film separating the accelerator vacuum from the cultivating liquid containing the cells in the air.

THPS008	Bucked Coils Lattice for the Neutrino Factory	3439
	A. Alekou, J. Pasternak Imperial College of Science and Technology, Department of Physics, London, United Kingdom C.T. Rogers STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
	In the Neutrino Factory muon front end, ionization cooling is used to reduce the very large initial transverse muon beam emittance. The current baseline cooling channel, FSIIA, performs well in simulations with respect to the transmission and cooling. However, recent studies indicate the RF voltage may be limited when external magnetic field is applied and therefore, as the FSIIA lattice has a large magnetic field at the position of the RF cavities, the feasibility of FSIIA may be questioned. Bucked Coils lattice, a new cooling lattice that uses different radius and opposite polarity coils placed at the same position along the beam-axis, aims to achieve low magnetic field at the position of the RF cavities while obtaining comparable transmission to FSIIA. The detailed comparison between FSIIA and different versions of the Bucked Coils configuration with respect to the magnetic field, beam dynamics and transmission are presented in this paper.

THPS009	Coherent Electron Cooling Demonstration Experiment	3442
	V. Litvinenko, S.A. Belomestnykh, I. Ben-Zvi, J. Bengtsson, A.V. Fedotov, Y. Hao, D. Kayran, G.J. Mahler, W. Meng, T. Rao, T. Roser, B. Sheehy, R. Than, J.E. Tuozzolo, G. Wang, V. Yakimenko BNL, Upton, Long Island, New York, USA G.I. Bell, D.L. Bruhwiler, V.H. Ranjbar, B.T. Schwartz Tech-X, Boulder, Colorado, USA A. Hutton, G.A. Krafft, M. Poelker, R.A. Rimmer JLAB, Newport News, Virginia, USA M.A. Kholopov, P. Vobly BINP SB RAS, Novosibirsk, Russia
	Coherent electron cooling (CEC) is considered to be on of potential candidates capable of cooling high-energy, high-intensity hadron beams to very small emittances. It also has a potential to significantly boost luminosity of high-energy hadron-hadron and electron-hadron colliders. In a CEC system, a perturbation of the electron density caused by a hadron is amplified and fed back to the hadrons to reduce the energy spread and the emittance of the beam. Following the funding decision by DoE office of Nuclear Physics, we are designing and building coherent electron cooler for a proof-of-principle experiment at RHIC to cool 40 GeV heavy ion beam. In this paper, we describe the layout of the CeC installed into IP2 interaction region at RHIC. We present the design of the CeC cooler and results of preliminary simulations.

Paper

Title

Page

Experimental Studies of Beam Loss during Low Energy Operation with Electron Cooled Heavy Ions in the ESR

3424

P.A. Görgen, O. Boine-Frankenheim
TEMF, TU Darmstadt, Darmstadt, Germany
S. Appel, C. Dimopoulou, S.A. Litvinov, M. Steck
GSI, Darmstadt, Germany

At the ESR at GSI electron cooled heavy ion beams are decelerated to 4 MeV/u and extracted for the HITRAP experiment. We will report about cooling equilibrium measurements at 4 and 30 MeV/u for Ar¹⁸⁺ coasting beams. We compare the equilibrium beam parameters with results from beam dynamics simulations using the BETACOOL code and an analytic model of reduced complexity. The time slot in which HITRAP accepts beam is 2μs long. For optimum efficiency the beam has to be bunched to this length before extraction. The obtained bunch profiles are compared to longitudinal beam dynamics simulations. Our measurements show that at both energies bunching leads to severe beam loss. The estimated transverse space charge tune shifts during the rf bunching indicate that resonance crossing might be responsible for the observed the beam loss. The influence of the tune shift will be further evaluated through resonance measurements.

THPS002

Progress of the 2 MeV Electron Cooler Development for COSY-Jülich/HESR

3427

J. Dietrich, V. Kamerdzhiev
FZJ, Jülich, Germany
M.I. Bryzgunov, A.D. Goncharov, V.M. Panasyuk, V.V. Parkhomchuk, V.B. Reva, D.N. Skorobogatov
BINP SB RAS, Novosibirsk, Russia

The 2 MeV electron cooling system for COSY-Jülich was proposed to further boost the luminosity even in presence of strong heating effects of high-density internal targets. The project is funded since mid 2009. The design and construction of the cooler is accomplished in cooperation with the Budker Institute of Nuclear Physics in Novosibirsk, Russia. The 2 MeV cooler is also well suited in the start up phase of the High Energy Storage Ring (HESR) at FAIR in Darmstadt. It can be used for beam cooling at injection energy and is intended to test new features of the high energy electron cooler for HESR. The infrastructure necessary for the operation of the cooler in the COSY ring (radiation shielding, cabling, water cooling etc.) is established. The electron beam commissioning at BINP Novosibirsk is scheduled to start at May of 2011. First results are reported. Final commissioning at COSY-Jülich is planned for the end of 2011.

THPS003

Status of Stochastic Cooling Predictions at the HESR

3430

H. Stockhorst, R. Maier, D. Prasuhn, R. Stassen
FZJ, Jülich, Germany
T. Katayama
GSI, Darmstadt, Germany

Detailed theoretical studies of stochastic cooling have been performed in order to fulfil the requirements for internal target experiments at the High-Energy Storage Ring (HESR) of the future Facility for Antiproton and Ion Research (FAIR) at the GSI in Darmstadt. A Fokker-Planck model and a particle tracking code utilizing the Filter and time-of-flight momentum cooling method have been developed for the 2 to 4 GHz cooling system. A barrier bucket cavity is included to compensate the mean energy loss due to the beam-target interaction. The code has been experimentally verified at the cooler synchrotron COSY. Since the RESR accumulator ring is postponed in the modularized start version of FAIR it is proposed to include the anti-proton accumulation function in the HESR downstream of the Collector Ring. Applying the radial stacking scheme well established at CERN and FNAL would result in a completely new and additional cooling system in the HESR. Instead a different way of beam accumulation has been selected that uses the already designed stochastic cooling system and the barrier bucket cavity of the HESR. Simulation results of the anti-proton accumulation in the HESR are presented.

THPS004

Beam Dynamics Simulation on Simultaneous use of Stochastic Cooling and Electron Cooling with Internal Target

3433

T. Kikuchi, N. Harada, T. Sasaki, H. Tamukai
Nagaoka University of Technology, Nagaoka, Niigata, Japan
T. Katayama
GSI, Darmstadt, Germany

The small momentum spread of proton beam has to be realized and kept in the storage ring during the experiment with a dense internal target. The stochastic cooling alone does not compensate the momentum spread increases due to the scattering at the internal target. The dense proton beam in the six dimensional phase space includes intra-beam scattering as one of emittance growth mechanisms. The numerical simulation is carried out using Fokker-Planck equation solver, and the results on the simultaneous use of stochastic cooling and electron cooling at COSY are indicated.

THPS006

Present Status of Beam Cooling and Related Research at S-LSR

3436

A. Noda, M. Nakao, H. Souda, H. Tongu
Kyoto ICR, Uji, Kyoto, Japan
T. Fujimoto, S.I. Iwata, S. Shibuya
AEC, Chiba, Japan
M. Grieser
MPI-K, Heidelberg, Germany
K. Ito, H. Okamoto
HU/AdSM, Higashi-Hiroshima, Japan
K. Jimbo
Kyoto IAE, Kyoto, Japan
K. Noda, T. Shirai
NIRS, Chiba-shi, Japan

Funding: Work supported by Advanced Compact Accelerator Development project of MEXT, and Global COE Program, "The Next Generation of Physics, Spun from Universality and Emergence" at Kyoto University.
With the use of Ion Storage and Cooler Ring, S-LSR at ICR, Kyoto University, Mg ion beam with 40 keV has been laser cooled not only in the longitudinal direction but also in the horizontal direction by "Synchro-Betatron Coupling". Laser cooling is now tried to be extended to vertical direction with horizontal and vertical coupling with the use of a solenoid magnetic field. At S-LSR, an electron beam cooling is also applied for 7MeV proton beam, resulting an ordered state. Electron beam cooling is also applied for rf captured bunched beam and a short pulse proton beam with the duration of ~3 ns is fast extracted in order to enable beam irradiation. A beam course is now being constructed to irradiate bio-molecular cells vertically from the bottom through a thin film separating the accelerator vacuum from the cultivating liquid containing the cells in the air.

THPS008

Bucked Coils Lattice for the Neutrino Factory

3439

A. Alekou, J. Pasternak
Imperial College of Science and Technology, Department of Physics, London, United Kingdom
C.T. Rogers
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom

In the Neutrino Factory muon front end, ionization cooling is used to reduce the very large initial transverse muon beam emittance. The current baseline cooling channel, FSIIA, performs well in simulations with respect to the transmission and cooling. However, recent studies indicate the RF voltage may be limited when external magnetic field is applied and therefore, as the FSIIA lattice has a large magnetic field at the position of the RF cavities, the feasibility of FSIIA may be questioned. Bucked Coils lattice, a new cooling lattice that uses different radius and opposite polarity coils placed at the same position along the beam-axis, aims to achieve low magnetic field at the position of the RF cavities while obtaining comparable transmission to FSIIA. The detailed comparison between FSIIA and different versions of the Bucked Coils configuration with respect to the magnetic field, beam dynamics and transmission are presented in this paper.

THPS009

Coherent Electron Cooling Demonstration Experiment

3442

V. Litvinenko, S.A. Belomestnykh, I. Ben-Zvi, J. Bengtsson, A.V. Fedotov, Y. Hao, D. Kayran, G.J. Mahler, W. Meng, T. Rao, T. Roser, B. Sheehy, R. Than, J.E. Tuozzolo, G. Wang, V. Yakimenko
BNL, Upton, Long Island, New York, USA
G.I. Bell, D.L. Bruhwiler, V.H. Ranjbar, B.T. Schwartz
Tech-X, Boulder, Colorado, USA
A. Hutton, G.A. Krafft, M. Poelker, R.A. Rimmer
JLAB, Newport News, Virginia, USA
M.A. Kholopov, P. Vobly
BINP SB RAS, Novosibirsk, Russia

Coherent electron cooling (CEC) is considered to be on of potential candidates capable of cooling high-energy, high-intensity hadron beams to very small emittances. It also has a potential to significantly boost luminosity of high-energy hadron-hadron and electron-hadron colliders. In a CEC system, a perturbation of the electron density caused by a hadron is amplified and fed back to the hadrons to reduce the energy spread and the emittance of the beam. Following the funding decision by DoE office of Nuclear Physics, we are designing and building coherent electron cooler for a proof-of-principle experiment at RHIC to cool 40 GeV heavy ion beam. In this paper, we describe the layout of the CeC installed into IP2 interaction region at RHIC. We present the design of the CeC cooler and results of preliminary simulations.