COOL2017 - Classification: Stochastic Cooling

Paper

Title

Page

Stochastic Cooling as Wiener Process

37

N. Shurkhno
FZJ, Jülich, Germany

Traditional theoretical description of stochastic cooling process involves either ordinary differential equations for desired rms quantities or corresponding Fokker-Planck equations. Both approaches use different methods of derivation and seem independent, making transition from one to another quite an issue, incidentally entangling somewhat the basic physics underneath. On the other hand, treatment of the stochastic cooling as Wiener pro-cess and starting from the single-particle dynamics written in the form of Langevin equation seems to bring more clarity and integrity. Present work is an attempt to apply Wiener process formalism to the stochastic cooling in order to have a simple and consistent way of deriving its well-known equations.

Poster TUP06 [0.414 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-COOL2017-TUP06

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TUP16

Latest News from Stochastic Cooling Developments for the Collector Ring at FAIR

64

R. Hettrich, A. Bardonner, R.M. Böhm, C. Dimopoulou, C. Peschke, A. Stuhl, S. Wunderlich
GSI, Darmstadt, Germany
F. Caspers
ESI, Archamps, France
F. Caspers
CERN, Geneva, Switzerland

The CR stochastic cooling system aims at fast 3D cooling of antiprotons, rare isotopes and stable ions. Because of the large apertures and the high gain needed to cool the hot secondary beams, damping within the 1-2 GHz band of the unwanted microwave modes propagating through the vacuum chambers is essential. It will be realised with UHV- compatible, resistively coated ceramic tubes and ferrites. The greatest challenge is increasing the signal to noise ratio for antiproton cooling by means of cryogenic movable (plunging) pickup electrodes, which follow the shrinking beam during cooling and then withdraw fast before the new injection. Linear motor drive units plunge synchroneously the pickup electrodes on both sides of the ion beam (horizontal/vertical). Their technical (mechanical, electrical, controls) concept and specification is summarized. Their performance has been demonstrated in successive measurements inside testing chambers at GSI. Recent simulations of the critical antiproton cooling with the designed system are shown. Longitudinal cooling and its simultaneous transverse cooling are studied with the Fokker-Planck code and with an analytical model, respectively.

Poster TUP16 [4.474 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-COOL2017-TUP16

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TUP17

Design of Stochastic Pick-Ups and Kickers for Low Beta Particle Beams

68

B. Breitkreutz, R. Stassen, H. Stockhorst
FZJ, Jülich, Germany

The COSY facility hosts experiments for the JEDI (Jülich Electric Dipole moment Investigations) collabora-tion. Polarized deuteron beams with a momentum of 970 MeV/c are stored in the ring. To achieve polarization times in the order of several minutes, small emittances and momentum spread are crucial. Therefore, the beam is pre-cooled with the 100-kV electron cooler. To further improve the spin coherence time, cooling during the experiments would be desirable. That way, the beam blow-up due to intra beam scattering could be compen-sated. But since the focusing solenoids in the e-cooler may not be perfectly compensated, it cannot be used to cool during the experiments. The existing stochastic cooling (SC) system is not sensitive at low beam veloci-ties. Thus, it is proposed to build a dedicated SC system for low beta beams. This work presents the proposed sys-tem. It emphasizes the design process of pick-up and kicker hardware. Starting from the slot-ring structures that have been developed for HESR, an optimization towards a high sensitivity at a beta of 0.46 is undertaken.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-COOL2017-TUP17

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TUP18

Stochastic Cooling Developments for the Spectrometer Ring (Sring) in the HIAF Project at IMP

G. Zhu, Z. Du, X.J. Hu, L. Jing, W. Wei, J.X. Wu, J.W. Xia, H.M. Xie, Y. Zhang
IMP/CAS, Lanzhou, People's Republic of China

We report on the preliminary design of Slot-ring and Faltin type pickups and kickers for stochastic pre-cooling of rare isotope beams from 625 MeV/u to 840 MeV/u (\beta: 0.80-0.85), or from 400 MeV/u to 625 MeV/u (\beta: 0.71-0.80), using a bandwidth of 1-2 GHz (or 0.6-1.2 GHz) for Spectrometer ring (Sring) in the HIAF project at IMP. The kicker shunt impedance and signal output phase of Slot-ring and Faltin type are calculated by HFSS. From the simulation results, Slot-ring structure is better for higher \beta (0.80-0.85), and Faltin type will be a better choice for \beta from 0.71 to 0.80 when the beam aperture is 200 mm*120 mm.

Poster TUP18 [2.015 MB]

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THA11

The HESR Stochastic Cooling System, Design, Construction and Test Experiments in COSY

89

R. Stassen, B. Breitkreutz, N. Shurkhno, H. Stockhorst
FZJ, Jülich, Germany
L. Thorndahl
CERN, Geneva, Switzerland

The construction phase of the stochastic cooling tanks for the HESR has started. Meanwhile two pickups (PU) and one kicker (KI) are fabricated. One PU and one KI are installed into the COSY ring for testing the new stochastic cooling system with real beam at various momenta. Small test-structures were already successfully operated at the Nuclotron in Dubna for longitudinal filter cooling but not for transverse cooling and as small PU in COSY. During the last COSY beam-time in 2017 additional transverse and ToF cooling were achieved. The first two series high power amplifiers were used for cooling and to test the temperature behavior of the combiner-boards at the KI. The system layout includes all components as planned for the HESR like low noise amplifier, switchable delay-lines and optical notch-filter. The HESR needs fast transmission-lines between PU and KI. Beside air-filled coax-lines, optical hollow fiber-lines are very attractive. First results with such a fiber used for the transverse signal path will be presented.

Slides THA11 [11.863 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-COOL2017-THA11

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THA12

Stochastic Cooling Plan and Experiments for HIAF and CSRe

J.X. Wu
IMP/CAS, Lanzhou, People's Republic of China

In December 2015 stochastic cooling of heavy ions was successfully applied for the first time at the CSRe storage ring of IMP in Lanzhou, China. During four days of commissioning, three-dimensional cooling could be observed. Both the time-of-flight and the notch filter methods were used for longitudinal cooling. The measured cooling rates are presented. In the end of December 2015, the project HIAF'High Intensity heavy ion Accelerator Facility was approved by the Chinese government. The project will be started to construct in 2018. Stochastic cooling will be built at the spectrometer ring (SRing) mainly for experiments with radioactive fragment beams with a large phase space, which is very similar to CSRe. After the stochastic pre-cooling, the subsequent electron cooling will further cool down the emittance and Dp/p to get extremely well-cooled beams. The primary design and the simulation results will be presented at the conference.

Slides THA12 [16.374 MB]

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THA13

Algorithmic Control of Stochastic Cooling Systems

N. Shurkhno, R. Stassen
FZJ, Jülich, Germany

Adjustment of stochastic cooling systems especially from scratch is usually very tedious and time-consuming, but at the same time it is quite straightforward and therefore could be made fully automatic. The basic parameters one should consider to set-up a stochastic cooling system are system delay and gain, and optionally a notch-filter frequency and attenuation. With proper algorithms the adjustment and control of these parameters could be done to the best accuracy and speed. To achieve this a universal software and hardware solutions were developed, allowing for fast automatic adjustment of stochastic cooling systems as well as for maintaining the adjustment during system operation without maintenance stops or beam disturbance. This report presents the developed approach for the automatic control and adjustment of stochastic cooling systems.

Slides THA13 [1.549 MB]

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Paper	Title	Page
TUP06	Stochastic Cooling as Wiener Process	37
	N. Shurkhno FZJ, Jülich, Germany
	Traditional theoretical description of stochastic cooling process involves either ordinary differential equations for desired rms quantities or corresponding Fokker-Planck equations. Both approaches use different methods of derivation and seem independent, making transition from one to another quite an issue, incidentally entangling somewhat the basic physics underneath. On the other hand, treatment of the stochastic cooling as Wiener pro-cess and starting from the single-particle dynamics written in the form of Langevin equation seems to bring more clarity and integrity. Present work is an attempt to apply Wiener process formalism to the stochastic cooling in order to have a simple and consistent way of deriving its well-known equations.
	Poster TUP06 [0.414 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-COOL2017-TUP06
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP16	Latest News from Stochastic Cooling Developments for the Collector Ring at FAIR	64
	R. Hettrich, A. Bardonner, R.M. Böhm, C. Dimopoulou, C. Peschke, A. Stuhl, S. Wunderlich GSI, Darmstadt, Germany F. Caspers ESI, Archamps, France F. Caspers CERN, Geneva, Switzerland
	The CR stochastic cooling system aims at fast 3D cooling of antiprotons, rare isotopes and stable ions. Because of the large apertures and the high gain needed to cool the hot secondary beams, damping within the 1-2 GHz band of the unwanted microwave modes propagating through the vacuum chambers is essential. It will be realised with UHV- compatible, resistively coated ceramic tubes and ferrites. The greatest challenge is increasing the signal to noise ratio for antiproton cooling by means of cryogenic movable (plunging) pickup electrodes, which follow the shrinking beam during cooling and then withdraw fast before the new injection. Linear motor drive units plunge synchroneously the pickup electrodes on both sides of the ion beam (horizontal/vertical). Their technical (mechanical, electrical, controls) concept and specification is summarized. Their performance has been demonstrated in successive measurements inside testing chambers at GSI. Recent simulations of the critical antiproton cooling with the designed system are shown. Longitudinal cooling and its simultaneous transverse cooling are studied with the Fokker-Planck code and with an analytical model, respectively.
	Poster TUP16 [4.474 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-COOL2017-TUP16
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP17	Design of Stochastic Pick-Ups and Kickers for Low Beta Particle Beams	68
	B. Breitkreutz, R. Stassen, H. Stockhorst FZJ, Jülich, Germany
	The COSY facility hosts experiments for the JEDI (Jülich Electric Dipole moment Investigations) collabora-tion. Polarized deuteron beams with a momentum of 970 MeV/c are stored in the ring. To achieve polarization times in the order of several minutes, small emittances and momentum spread are crucial. Therefore, the beam is pre-cooled with the 100-kV electron cooler. To further improve the spin coherence time, cooling during the experiments would be desirable. That way, the beam blow-up due to intra beam scattering could be compen-sated. But since the focusing solenoids in the e-cooler may not be perfectly compensated, it cannot be used to cool during the experiments. The existing stochastic cooling (SC) system is not sensitive at low beam veloci-ties. Thus, it is proposed to build a dedicated SC system for low beta beams. This work presents the proposed sys-tem. It emphasizes the design process of pick-up and kicker hardware. Starting from the slot-ring structures that have been developed for HESR, an optimization towards a high sensitivity at a beta of 0.46 is undertaken.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-COOL2017-TUP17
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP18	Stochastic Cooling Developments for the Spectrometer Ring (Sring) in the HIAF Project at IMP
	G. Zhu, Z. Du, X.J. Hu, L. Jing, W. Wei, J.X. Wu, J.W. Xia, H.M. Xie, Y. Zhang IMP/CAS, Lanzhou, People's Republic of China
	We report on the preliminary design of Slot-ring and Faltin type pickups and kickers for stochastic pre-cooling of rare isotope beams from 625 MeV/u to 840 MeV/u (\beta: 0.80-0.85), or from 400 MeV/u to 625 MeV/u (\beta: 0.71-0.80), using a bandwidth of 1-2 GHz (or 0.6-1.2 GHz) for Spectrometer ring (Sring) in the HIAF project at IMP. The kicker shunt impedance and signal output phase of Slot-ring and Faltin type are calculated by HFSS. From the simulation results, Slot-ring structure is better for higher \beta (0.80-0.85), and Faltin type will be a better choice for \beta from 0.71 to 0.80 when the beam aperture is 200 mm*120 mm.
	Poster TUP18 [2.015 MB]
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THA11	The HESR Stochastic Cooling System, Design, Construction and Test Experiments in COSY	89
	R. Stassen, B. Breitkreutz, N. Shurkhno, H. Stockhorst FZJ, Jülich, Germany L. Thorndahl CERN, Geneva, Switzerland
	The construction phase of the stochastic cooling tanks for the HESR has started. Meanwhile two pickups (PU) and one kicker (KI) are fabricated. One PU and one KI are installed into the COSY ring for testing the new stochastic cooling system with real beam at various momenta. Small test-structures were already successfully operated at the Nuclotron in Dubna for longitudinal filter cooling but not for transverse cooling and as small PU in COSY. During the last COSY beam-time in 2017 additional transverse and ToF cooling were achieved. The first two series high power amplifiers were used for cooling and to test the temperature behavior of the combiner-boards at the KI. The system layout includes all components as planned for the HESR like low noise amplifier, switchable delay-lines and optical notch-filter. The HESR needs fast transmission-lines between PU and KI. Beside air-filled coax-lines, optical hollow fiber-lines are very attractive. First results with such a fiber used for the transverse signal path will be presented.
	Slides THA11 [11.863 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-COOL2017-THA11
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THA12	Stochastic Cooling Plan and Experiments for HIAF and CSRe
	J.X. Wu IMP/CAS, Lanzhou, People's Republic of China
	In December 2015 stochastic cooling of heavy ions was successfully applied for the first time at the CSRe storage ring of IMP in Lanzhou, China. During four days of commissioning, three-dimensional cooling could be observed. Both the time-of-flight and the notch filter methods were used for longitudinal cooling. The measured cooling rates are presented. In the end of December 2015, the project HIAF'High Intensity heavy ion Accelerator Facility was approved by the Chinese government. The project will be started to construct in 2018. Stochastic cooling will be built at the spectrometer ring (SRing) mainly for experiments with radioactive fragment beams with a large phase space, which is very similar to CSRe. After the stochastic pre-cooling, the subsequent electron cooling will further cool down the emittance and Dp/p to get extremely well-cooled beams. The primary design and the simulation results will be presented at the conference.
	Slides THA12 [16.374 MB]
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THA13	Algorithmic Control of Stochastic Cooling Systems
	N. Shurkhno, R. Stassen FZJ, Jülich, Germany
	Adjustment of stochastic cooling systems especially from scratch is usually very tedious and time-consuming, but at the same time it is quite straightforward and therefore could be made fully automatic. The basic parameters one should consider to set-up a stochastic cooling system are system delay and gain, and optionally a notch-filter frequency and attenuation. With proper algorithms the adjustment and control of these parameters could be done to the best accuracy and speed. To achieve this a universal software and hardware solutions were developed, allowing for fast automatic adjustment of stochastic cooling systems as well as for maintaining the adjustment during system operation without maintenance stops or beam disturbance. This report presents the developed approach for the automatic control and adjustment of stochastic cooling systems.
	Slides THA13 [1.549 MB]
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)