COOL2013 - List of Authors (Prasuhn, D.)

Paper

Title

Page

Stochastic Cooling of a Polarized Proton Beam at COSY

44

H. Stockhorst, R. Gebel, V. Kamerdzhiev, A. Lehrach, B. Lorentz, R. Maier, D. Prasuhn, R. Stassen
FZJ, Jülich, Germany
T. Katayama
GSI, Darmstadt, Germany

Stochastic cooling can increase the spin coherence time in storage ring experiments dedicated to the search of electric dipole moments of protons or deuterons. Since radial magnetic fields may lead to depolarizing spin resonances a first test with a vertical polarized beam at COSY subject to vertical stochastic cooling has been investigated. The polarization was measured at the beginning and the end of flat top momentum with the result that no polarization loss could be observed within five minutes. The spin motion under the influence of stochastic cooling was also studied with the Thomas-BMT equation including the estimated electromagnetic fields for a quarter wave length kicker structure. It is found that the resonance strength in the cooling bandwidth of 1-2 GHz is much smaller than the typical imperfection or intrinsic resonance strengths. The resonance condition of the spin rotation is not fulfilled as the harmonics of cooling RF kicker fields are not in phase with the spin rotation angle per turn. In conclusion it is expected that stochastic cooling will not lead to depolarization even when stochastic cooling is applied for a longer time as in the present experiment.

Slides TUAM1HA02 [2.324 MB]

THPM2HA02

Overview of the HESR

D. Prasuhn
FZJ, Jülich, Germany

The High Energy Storage Ring (HESR) at the Facility for Antiproton and Ion Research (FAIR) is being designed and will be constructed by a consortium of several institutes from different countries under the leadership of R. Maier (Forschungszentrum Jülich). It was designed for storage and acceleration of anti-protons in the momentum range between 1.5 and 15 GeV/c for the PANDA experiment. As the modularized start version delayed the low energy storage ring for ion research the SPARC collaboration triggered first ideas to accelerate heavy ions in the HESR. Detailed studies about the storage, acceleration and cooling of heavy ions in the HESR in the magnetic rigidity regime of the HESR (5 to 50 Tm) proved the possibility of high quality experiments with heavy ions in the HESR. Results of the beam dynamic simulations for heavy ions as well as studies of the accumulation process of anti-protons in the HESR will be shown.

Slides THPM2HA02 [1.026 MB]

FRAM2HA04

Recollections of Dieter

D. Prasuhn
FZJ, Jülich, Germany

Recollections of Dieter

Slides FRAM2HA04 [1.311 MB]

Paper	Title	Page
TUAM1HA02	Stochastic Cooling of a Polarized Proton Beam at COSY	44
	H. Stockhorst, R. Gebel, V. Kamerdzhiev, A. Lehrach, B. Lorentz, R. Maier, D. Prasuhn, R. Stassen FZJ, Jülich, Germany T. Katayama GSI, Darmstadt, Germany
	Stochastic cooling can increase the spin coherence time in storage ring experiments dedicated to the search of electric dipole moments of protons or deuterons. Since radial magnetic fields may lead to depolarizing spin resonances a first test with a vertical polarized beam at COSY subject to vertical stochastic cooling has been investigated. The polarization was measured at the beginning and the end of flat top momentum with the result that no polarization loss could be observed within five minutes. The spin motion under the influence of stochastic cooling was also studied with the Thomas-BMT equation including the estimated electromagnetic fields for a quarter wave length kicker structure. It is found that the resonance strength in the cooling bandwidth of 1-2 GHz is much smaller than the typical imperfection or intrinsic resonance strengths. The resonance condition of the spin rotation is not fulfilled as the harmonics of cooling RF kicker fields are not in phase with the spin rotation angle per turn. In conclusion it is expected that stochastic cooling will not lead to depolarization even when stochastic cooling is applied for a longer time as in the present experiment.
	Slides TUAM1HA02 [2.324 MB]

THPM2HA02	Overview of the HESR
	D. Prasuhn FZJ, Jülich, Germany
	The High Energy Storage Ring (HESR) at the Facility for Antiproton and Ion Research (FAIR) is being designed and will be constructed by a consortium of several institutes from different countries under the leadership of R. Maier (Forschungszentrum Jülich). It was designed for storage and acceleration of anti-protons in the momentum range between 1.5 and 15 GeV/c for the PANDA experiment. As the modularized start version delayed the low energy storage ring for ion research the SPARC collaboration triggered first ideas to accelerate heavy ions in the HESR. Detailed studies about the storage, acceleration and cooling of heavy ions in the HESR in the magnetic rigidity regime of the HESR (5 to 50 Tm) proved the possibility of high quality experiments with heavy ions in the HESR. Results of the beam dynamic simulations for heavy ions as well as studies of the accumulation process of anti-protons in the HESR will be shown.
	Slides THPM2HA02 [1.026 MB]

FRAM2HA04	Recollections of Dieter
	D. Prasuhn FZJ, Jülich, Germany
	Recollections of Dieter
	Slides FRAM2HA04 [1.311 MB]