COOL2013 - List of Authors (Dimopoulou, C.)

Paper

Title

Page

Progress of the Stochastic Cooling System of the Collector Ring

40

C. Dimopoulou, D. Barker, R.M. Böhm, A. Dolinskyy, B. J. Franzke, R. Hettrich, W. Maier, R. Menges, F. Nolden, C. Peschke, P. Petri, M. Steck
GSI, Darmstadt, Germany
L. Thorndahl
CERN, Geneva, Switzerland

An overview of the recent achievements and ongoing developments for the stochastic cooling system of the Collector Ring is given. In focus are the hardware developments as well as the progress in predicting the system performance. The system operates in the frequency band 1-2 GHz, it has to provide fast 3D cooling of antiproton, rare isotope and stable heavy ion beams. The main challenges are (i) the cooling of antiprotons by means of cryogenic movable pick-up electrodes and (ii) the fast two-stage cooling (pre-cooling by the Palmer method, followed by the notch filter method) of the hot rare isotopes. Recently, a novel code for simulating the cooling process in the time domain has been developed at CERN. First results for the momentum cooling for heavy ions in the CR will be shown in comparison with results obtained in the frequency domain with the Fokker-Planck equation.

Slides TUAM1HA01 [4.320 MB]

TUAM1HA04

Simulation Study of Stochastic Cooling of Heavy Ion Beam at the Collector Ring of FAIR

52

T. Katayama, C. Dimopoulou, A. Dolinskyy, F. Nolden, M. Steck
GSI, Darmstadt, Germany

In the modularized start version of the FAIR project, the New Experimental Storage Ring is not included and therefore the task of the stochastic cooling system at the Collector Ring (CR) has been until now focused on the 3 GeV anti-proton beam. On the other hand, recently the SPARC collaboration has proposed to start the high energy atomic physics experiments in the HESR ring with stable ions, typically a ²³⁸U⁹²⁺ beam, implementing the internal target. Furthermore the future possibility of the nuclear physics experiments with rare isotope beams, typically ¹³²Sn⁵⁰⁺ beam, in the HESR is envisaged. In the present report, the beam dynamics, mainly the longitudinal motion from the front-end (superconducting fragment separator) to the back-end (fast extraction from the CR) are described emphasizing the process of stochastic cooling of the rare isotope beam.

Slides TUAM1HA04 [2.504 MB]

WEPPO19

The Novel Optical Notch Filter for Stochastic Cooling at the ESR

142

W. Maier, C. Dimopoulou, R. Hettrich, F. Nolden, C. Peschke, P. Petri, M. Steck
GSI, Darmstadt, Germany

In the frame of the development for the FAIR facility at GSI, notch filter cooling is essential for the stochastic cooling system of the CR (Collector Ring). A prototype notch filter based on optical components has been developed and built. The focus was to achieve sufficient notch depth and low dispersion of the filter transfer function. The compact optical notch filter was integrated into the ESR stochastic cooling system. Momentum cooling of heavy ion beams was successfully demonstrated. The layout of the notch filter as well as experimental results are presented

WEPPO20

RF-System for Stochastic Cooling in the FAIR Collector Ring

146

C. Peschke, R.M. Böhm, C. Dimopoulou, F. Nolden, P. Petri
GSI, Darmstadt, Germany

The collector ring (CR) of the FAIR project is designed for fast stochastic cooling of rare isotope and antiproton beams injected at different velocities. A flexible rf signal processing scheme for the stochastic cooling system will be presented. It includes cooling with time of flight (TOF), notch filter and Palmer methods. A Palmer pick-up with Faltin electrodes is foreseen for pre-cooling of hot rare isotope beams. For TOF and notch filter methods, a horizontal and a vertical pick-up tank with movable cryogenic slotline electrodes for ions with two different velocities is under development. The layout of this slotline pick-up tank will also be presented.

Poster WEPPO20 [2.410 MB]

WEPPO21

Design of the Palmer Pickup for Stochastic Pre-cooling of Heavy Ions at the CR

149

L. Thorndahl
CERN, Geneva, Switzerland
D. Barker, C. Dimopoulou, C. Peschke
GSI, Darmstadt, Germany

We detail the design and optimisation of modified Faltin type pick-ups for the pre-cooling of heavy ions in the CR ring at GSI. The design challenge includes simultaneous optimisation of large pick-up impedance, 50 Ω characteristic impedance, frequency independence over a large bandwidths and phase velocity matched to particle velocity. Although heavy ions offer large signals due to their charge, their relatively slow velocity is difficult to match in Faltin type pick-ups while maintaining a flat frequency response and a 50 Ω characteristic impedance. We explain the design process, and show how multiple parameters are simultaneously optimised using genetic algorithms, which are suitable for optimization problems with large and complex search spaces.

THAM1HA04

Laser Cooling of Relativistic C³⁺ Ion Beams with a Large Initial Momentum Spread

166

D.F.A. Winters, C.J. Clark, C. Dimopoulou, T. Giacomini, C. Kozhuharov, T. Kühl, Yu.A. Litvinov, M. Lochmann, W. Nörtershäuser, F. Nolden, R.M. Sanchez Alarcon, M.S. Sanjari, M. Steck, T. Stöhlker, J. Ullmann
GSI, Darmstadt, Germany
T. Beck, G. Birkl, B. Rein, S. Tichelmann, T. Walther
TU Darmstadt, Darmstadt, Germany
M.H. Bussmann, U. Schramm, M. Seltmann
Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiation Physics, Dresden, Germany
X. Ma, W.Q. Wen, J. Yang, D. Zhang
IMP, Lanzhou, People's Republic of China
M. Siebold
HZDR, Dresden, Germany

We present new results on broadband laser cooling of stored relativistic C³⁺ ion beams at the ESR in Darmstadt. For the first time we could show laser cooling of bunched relativistic ion beams using a UV-laser which could scan over a very large range and thus cool all the ions in the ‘bucket’. This scheme is much more versatile than a previous scheme, where the bunching frequency was scanned relative to a fixed laser frequency. We have also demonstrated that this cooling scheme works without pre-electron cooling, which is a pre-requisite for its general application to future storage rings and synchrotrons, such as the HESR and the SIS100 at FAIR. We also present results from in vacuo UV-fluorescence detectors, which have proven to be very effective.

Slides THAM1HA04 [4.231 MB]

Paper	Title	Page
TUAM1HA01	Progress of the Stochastic Cooling System of the Collector Ring	40
	C. Dimopoulou, D. Barker, R.M. Böhm, A. Dolinskyy, B. J. Franzke, R. Hettrich, W. Maier, R. Menges, F. Nolden, C. Peschke, P. Petri, M. Steck GSI, Darmstadt, Germany L. Thorndahl CERN, Geneva, Switzerland
	An overview of the recent achievements and ongoing developments for the stochastic cooling system of the Collector Ring is given. In focus are the hardware developments as well as the progress in predicting the system performance. The system operates in the frequency band 1-2 GHz, it has to provide fast 3D cooling of antiproton, rare isotope and stable heavy ion beams. The main challenges are (i) the cooling of antiprotons by means of cryogenic movable pick-up electrodes and (ii) the fast two-stage cooling (pre-cooling by the Palmer method, followed by the notch filter method) of the hot rare isotopes. Recently, a novel code for simulating the cooling process in the time domain has been developed at CERN. First results for the momentum cooling for heavy ions in the CR will be shown in comparison with results obtained in the frequency domain with the Fokker-Planck equation.
	Slides TUAM1HA01 [4.320 MB]

TUAM1HA04	Simulation Study of Stochastic Cooling of Heavy Ion Beam at the Collector Ring of FAIR	52
	T. Katayama, C. Dimopoulou, A. Dolinskyy, F. Nolden, M. Steck GSI, Darmstadt, Germany
	In the modularized start version of the FAIR project, the New Experimental Storage Ring is not included and therefore the task of the stochastic cooling system at the Collector Ring (CR) has been until now focused on the 3 GeV anti-proton beam. On the other hand, recently the SPARC collaboration has proposed to start the high energy atomic physics experiments in the HESR ring with stable ions, typically a ²³⁸U⁹²⁺ beam, implementing the internal target. Furthermore the future possibility of the nuclear physics experiments with rare isotope beams, typically ¹³²Sn⁵⁰⁺ beam, in the HESR is envisaged. In the present report, the beam dynamics, mainly the longitudinal motion from the front-end (superconducting fragment separator) to the back-end (fast extraction from the CR) are described emphasizing the process of stochastic cooling of the rare isotope beam.
	Slides TUAM1HA04 [2.504 MB]

WEPPO19	The Novel Optical Notch Filter for Stochastic Cooling at the ESR	142
	W. Maier, C. Dimopoulou, R. Hettrich, F. Nolden, C. Peschke, P. Petri, M. Steck GSI, Darmstadt, Germany
	In the frame of the development for the FAIR facility at GSI, notch filter cooling is essential for the stochastic cooling system of the CR (Collector Ring). A prototype notch filter based on optical components has been developed and built. The focus was to achieve sufficient notch depth and low dispersion of the filter transfer function. The compact optical notch filter was integrated into the ESR stochastic cooling system. Momentum cooling of heavy ion beams was successfully demonstrated. The layout of the notch filter as well as experimental results are presented

WEPPO20	RF-System for Stochastic Cooling in the FAIR Collector Ring	146
	C. Peschke, R.M. Böhm, C. Dimopoulou, F. Nolden, P. Petri GSI, Darmstadt, Germany
	The collector ring (CR) of the FAIR project is designed for fast stochastic cooling of rare isotope and antiproton beams injected at different velocities. A flexible rf signal processing scheme for the stochastic cooling system will be presented. It includes cooling with time of flight (TOF), notch filter and Palmer methods. A Palmer pick-up with Faltin electrodes is foreseen for pre-cooling of hot rare isotope beams. For TOF and notch filter methods, a horizontal and a vertical pick-up tank with movable cryogenic slotline electrodes for ions with two different velocities is under development. The layout of this slotline pick-up tank will also be presented.
	Poster WEPPO20 [2.410 MB]

WEPPO21	Design of the Palmer Pickup for Stochastic Pre-cooling of Heavy Ions at the CR	149
	L. Thorndahl CERN, Geneva, Switzerland D. Barker, C. Dimopoulou, C. Peschke GSI, Darmstadt, Germany
	We detail the design and optimisation of modified Faltin type pick-ups for the pre-cooling of heavy ions in the CR ring at GSI. The design challenge includes simultaneous optimisation of large pick-up impedance, 50 Ω characteristic impedance, frequency independence over a large bandwidths and phase velocity matched to particle velocity. Although heavy ions offer large signals due to their charge, their relatively slow velocity is difficult to match in Faltin type pick-ups while maintaining a flat frequency response and a 50 Ω characteristic impedance. We explain the design process, and show how multiple parameters are simultaneously optimised using genetic algorithms, which are suitable for optimization problems with large and complex search spaces.

THAM1HA04	Laser Cooling of Relativistic C³⁺ Ion Beams with a Large Initial Momentum Spread	166
	D.F.A. Winters, C.J. Clark, C. Dimopoulou, T. Giacomini, C. Kozhuharov, T. Kühl, Yu.A. Litvinov, M. Lochmann, W. Nörtershäuser, F. Nolden, R.M. Sanchez Alarcon, M.S. Sanjari, M. Steck, T. Stöhlker, J. Ullmann GSI, Darmstadt, Germany T. Beck, G. Birkl, B. Rein, S. Tichelmann, T. Walther TU Darmstadt, Darmstadt, Germany M.H. Bussmann, U. Schramm, M. Seltmann Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiation Physics, Dresden, Germany X. Ma, W.Q. Wen, J. Yang, D. Zhang IMP, Lanzhou, People's Republic of China M. Siebold HZDR, Dresden, Germany
	We present new results on broadband laser cooling of stored relativistic C³⁺ ion beams at the ESR in Darmstadt. For the first time we could show laser cooling of bunched relativistic ion beams using a UV-laser which could scan over a very large range and thus cool all the ions in the ‘bucket’. This scheme is much more versatile than a previous scheme, where the bunching frequency was scanned relative to a fixed laser frequency. We have also demonstrated that this cooling scheme works without pre-electron cooling, which is a pre-requisite for its general application to future storage rings and synchrotrons, such as the HESR and the SIS100 at FAIR. We also present results from in vacuo UV-fluorescence detectors, which have proven to be very effective.
	Slides THAM1HA04 [4.231 MB]