COOL2013 - List of Authors (Stassen, R.)

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]

TUPM1HA01

Study for Stochastic Cooling at Nuclotron, JINR

73

N. Shurkhno, A.O. Sidorin, G.V. Trubnikov
JINR, Dubna, Moscow Region, Russia
T. Katayama
GSI, Darmstadt, Germany
R. Stassen
FZJ, Jülich, Germany

The experiment on stochastic cooling at Nuclotron, initiated two years ago as a test bench for NICA collider, is progressing well. New scheme of cooling system, which includes ring-slot couplers as pick-up and kicker (designed at FZJ), optical notch-filter and full remote-controlled automation of measurements and adjustments, was set in operation in autumn 2012. This report presents results of beam cooling modeling, experimental measurements of the optical notch-filter and channel elements performed in 2011-2012, and also first results of the beam cooling achieved at Nuclotron in March 2013.

Slides TUPM1HA01 [1.817 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]

TUPM1HA01	Study for Stochastic Cooling at Nuclotron, JINR	73
	N. Shurkhno, A.O. Sidorin, G.V. Trubnikov JINR, Dubna, Moscow Region, Russia T. Katayama GSI, Darmstadt, Germany R. Stassen FZJ, Jülich, Germany
	The experiment on stochastic cooling at Nuclotron, initiated two years ago as a test bench for NICA collider, is progressing well. New scheme of cooling system, which includes ring-slot couplers as pick-up and kicker (designed at FZJ), optical notch-filter and full remote-controlled automation of measurements and adjustments, was set in operation in autumn 2012. This report presents results of beam cooling modeling, experimental measurements of the optical notch-filter and channel elements performed in 2011-2012, and also first results of the beam cooling achieved at Nuclotron in March 2013.
	Slides TUPM1HA01 [1.817 MB]