COOL2017 - Table of Session: TUP (Poster Session)

Paper	Title	Page
TUP01	Beam Tracking Studies of Electron Cooling in ELENA
	J. Resta-López, J.R. Hunt, B. Veglia, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom
	The Extra Low ENergy Antiproton storage ring (ELENA), which is a new small synchrotron currently being commissioned at CERN, will further decelerate antiprotons from the Antiproton Decelerator (AD) from 5.3 MeV to energies as low as 100 keV and provide high quality beams for antimatter experiments. At such unprecedented low energy, it is important to evaluate the long term beam stability. To provide a consistent explanation of the different physical effects acting on the beam, multi-particle and multi-turn tracking simulations have been performed in the ELENA ring, including electron cooling and different scattering effects under realistic assumptions. The effect of several imperfections in the electron cooling process is also analysed. The aim is to make a comparison with measurements, thus obtaining a full characterisation of the beam evolution in ELENA.
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP02	Emittance Measurement of Cooled Beams
	J. Resta-López, J.R. Hunt, B. Veglia, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom
	Precise emittance measurements are essential to guarantee optimum beam control and performance in all kind of accelerator machines. Amongst them, ultra-low energy antiproton and ion facilities, where beam cooling is essential, are not an exception. In these machines, the emittance reconstruction techniques have to face several challenges, e.g. asymmetric beams, long beam profile tails, diffusion and space charge effects. In addition, likely in a strongly cooled beam there will appear a high correlation between momentum offset and transverse emittance. In this contribution, we investigate effective reconstruction algorithms based in scraping techniques in presence of the above effects. Simulation results are presented for the case of the Extra Low ENergy Antiproton storage ring (ELENA), which is currently being commissioned at CERN.
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP04	Muon Intensity Increase by Wedge Absorbers for low-E Muon Experiments	32
	D.V. Neuffer, J. Bradley, D. Stratakis Fermilab, Batavia, Illinois, USA
	Low energy muon experiments such as mu2e and g-2 have a limited energy spread acceptance. Following techniques developed in muon cooling studies and the MICE experiment, the number of muons within the desired energy spread can be increased by the matched use of wedge absorbers. More generally, the phase space of muon beams can be manipulated by absorbers in beam transport lines. Applications with simulation results are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-COOL2017-TUP04
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP05	Towards Laser Cooling of Relativistic ¹⁶O⁵⁺ Ion Beams at the CSRe
	H.B. Wang, B. Hai, Z. Huang, J. Li, X.N. Li, X. Ma, L.J. Mao, R.S. Mao, W.Q. Wen, J.X. Wu, J.C. Yang, Y.J. Yuan, D. Zhang, D. Zhao IMP/CAS, Lanzhou, People's Republic of China M.H. Bussmann HZDR, Dresden, Germany D.F.A. Winters GSI, Darmstadt, Germany
	Laser cooling is one of the most promising techniques to achieve high phase-space densities or even crystalline beams for relativistic heavy ion beams at storage rings []. In addition, precision laser spectroscopy of relevant transitions in highly charged ions can also be performed simultaneously during the laser cooling experiments []. In the storage ring CSRe at IMP, a new laser cooling experiment for Li-like ¹⁶O⁵⁺ ion beams is currently being prepared and will be carried out at the end of the year 2017 under the Laser-cooling Collaboration. During the experiment, a CW laser with a wavelength of 220 nm will be used to cool the ¹⁶O⁵⁺ ion beams with an energy of 280 MeV/u. The ¹⁶O⁵⁺ ion beams will be the highest charge state and highest energy ions ever used for laser cooling at the storage rings. In the experiment, the longitudinally dynamics of ultra-cold ion beams will be investigate systematically towards the transition of the space charge dominated regime. Precision laser spectroscopy of ¹⁶O⁵⁺ ions for measuring the transition energy of 2s1/2'2p1/2 and 2s1/2'2p3/2 is foreseen. [] U. Schramm et al., Progress in Particle and Nuclear Physics, 53 (2004) 583-677. [**] U. Schramm et al., Hyperfine Interactions 162(1) (2005), 181-188
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

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)

TUP07	Secondary Electron and Photon Measurements at the HIM Electron Cooler Test Set-Up
	Th. Beiser IKP, Mainz, Germany K. Aulenbacher, M.W. Bruker, T. Weilbach HIM, Mainz, Germany
	A low-energy test set-up for the measurement and optimisation of secondary electron currents from the collector in electron coolers is presented. A variable-field Wien filter and current-measuring aperture plates grant insight into the trajectory and energy distribution of the secondary particles. Photons emitted by residual gas ions trapped inside the electromagnetic potential of the electron beam can be used to measure the location of the beam. The exact composition of those ions, the optical spectrum of said photons, and the possibility of related beam diagnostics is a subject of ongoing research.
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP08	Preliminary Design of Electron Target for SRing at HIAF	40
	J. Li, Z. Huang, L.J. Mao, M.T. Tang, S. X. Wang, J.C. Yang, X.D. Yang, H. Zhao, L.X. Zhao IMP/CAS, Lanzhou, People's Republic of China
	A 13 Tm multifunction storage ring dedicated to nucleon and atomic experiment research - the SRing (Spectrometry Ring) is a significant part of the new heavy-ion research complex - HIAF (High Intensity heavy ion Accelerator Facility). In additional to an electron cooler and a gas internal target planned at the SRing, a beam of low temperature electron is also required to collide with the storage beam and to cool the decelerated ion beam at low energy. A magnetic adiabatic expansion is proposed to attain a low temperature by applying a 1.2 T longitudinal magnetic field upon the thermionic cathode at the electron gun. In this paper, preliminary design of the electron target is introduced.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-COOL2017-TUP08
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP09	Project of High-Voltage System with Fast Changing Potential for DR Experiment	44
	V.B. Reva, A.P. Denisov, V.V. Parkhomchuk, A.A. Putmakov, D.N. Skorobogatov BINP SB RAS, Novosibirsk, Russia J. Li, X. Ma, L.J. Mao IMP/CAS, Lanzhou, People's Republic of China
	Funding: The reported study was partially funded by RFBR 16-52-53016. A storage ring equipped with an electron cooler is an ideal platform for dielectronic recombination (DR)experiments. In order to fulfill the requirement of DR measurements the system of the precision control of the relative energy between the ion beam and the electron beam should be installed in the electron cooler device. This report describes the project of such system that is designed with section approach like COSY electron cooler. Each section consist of the section of cascade transformer and two power supplies for low and fast detuning of potential of high-voltage terminal. This project can be used in CSRe and future HIAF storage rings.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-COOL2017-TUP09
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP10	Electron Cooling Simulation and Benchmarks
	A. Latina, N. Biancacci CERN, Geneva, Switzerland
	Electron Cooling is a method of damping betratron oscillations of heavy particles, like protons, antiprotons, and ions, through the interaction with cold electrons at small relative velocity. A detailed simulation of the Electron Cooling process has been created using a hybrid kinetic model, where the full 6d phase space of a multi-particle beam is immersed in a fluid plasma of electrons. This simulation has been implemented in the tracking code RF-Track, with the aim of exploring the performance of electron coolers in presence of realistic imperfections. Simulations results, and benchmarks against experimental data measured at CERN at LEIR, are presented and discussed in this poster.
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP11	The Interaction Between Electrons and Ions in Comoving and Static Electron Columns	47
	V.A. Britten, M. Droba, O. Meusel, H. Podlech, A. Schempp, K. Schulte IAP, Frankfurt am Main, Germany
	The interaction between electrons and positive ion beams and its application in accelerator physics are investigated. A space charge lens named Gabor lens was developed which confines electrons in a static column by external fields. The confined electrons are used for focusing and may support space charge compensation. In this structure the relative velocity between the ions and the electrons is maximal and corresponds to the beam velocity. An electron lens as at the Tevatron* is operated with a lower relative velocity in order to compensate the beam, to clean the beam abort gap or to excite the beam for beam dynamics measurements. In comparison electron cooling needs the same velocity of the ion and the electron beam. The following study contains the superposition of electric and magnetic self-fields and their impact on the density distribution of the ion beam and of the electron beam. Recombinations and ionisations are neglected. This is the beginning of an interface between these topics to find differences and similarities of the interaction between ions and electrons with different relative velocities. This may open up opportunities e.g. for the diagnostics of particle beams. * Shiltsev, Vladimir, et al. "Tevatron electron lenses: Design and operation." Physical Review Special Topics-Accelerators and Beams 11.10 (2008): 103501.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-COOL2017-TUP11
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP12	Simulation of Low Enery Ion Beam Cooling With Pulsed Electron Beam on CSRm	50
	H. Zhao, J. Li, L.J. Maopresenter, M.T. Tang, J.C. Yang, X.D. Yang IMP/CAS, Lanzhou, People's Republic of China
	The pulsed electron beam can be applied to high ener-gy beam cooling and the researches of ion-electron inter-action in the future. In this paper, we studied the pulsed e-beam cooling effects on coasting and bunched ion beam by simulation code which is based on the theory of elec-tron cooling, IBS and space charge effect etc. In the simu-lation, a rectangular distribution of electron beam was applied to 7 MeV/u 12C⁶⁺ ion beam on CSRm. It is found that the coasting ion beam was bunched by the pulsed e-beam and the rising and falling region of electron beam current play an important role for the bunching effect, and similar phenomenon was found for the bunched ion beam. In addition, the analyses of these phenomena in simulation were discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-COOL2017-TUP12
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP13	Calculations of the Gun and Collector for Electron Cooling Systems of HIAF	54
	M.T. Tang, J. Li, H.J. Lu, X.M. Ma, L.J. Mao, T.L. Yan, X.D. Yang, H. Zhao, L.X. Zhao IMP/CAS, Lanzhou, People's Republic of China A.V. Ivanov BINP SB RAS, Novosibirsk, Russia
	Two electron coolers are designed for the new project HIAF, one cooler with the highest energy 50keV is for the booster ring (BRing) to decreasing the transverse emittance of injected beams and another one with the highest energy 450keV is for the high precision Spec-trometer Ring (SRing). In this paper the results of the gun and collector simulation for these two electron coolers are presented. After optimization, the gun can produce 2A profile variable electron beam. The one time collecting efficiency is higher than 99.99%. The results of electron motions in toroid calculated by a numerical method are also summarized in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-COOL2017-TUP13
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP14	Investigation on the Suppression of Intrabeam Scattering in the High Intensity Heavy Ion Beam with the help of Longitudinal Multi-bunch Chain of Electron	58
	X.D. Yang, J. Li, X.M. Ma, L.J. Mao, M.T. Tang, T.L. Yan, H. Zhao IMP/CAS, Lanzhou, People's Republic of China
	Intrabeam scattering is the main reason of degradation of the beam brightness and shortening of brightness lifetime in the collider, light source and storage ring. The intrabeam scattering presents dissimilar influence in the different facilities. Electron cooling was chose to suppress the effect of intrabeam scattering, another unexpected effect happened during the cooling. The distribution of ion beam quickly deviates from the initial Gaussian type, form a denser core and long tail. The ions standing in the tail of beam will loss soon due to large amplitude. This solution will focus on the investigation on the suppression of intrabeam scattering in the high intensity heavy ion beam in the storage ring with the help of longitudinally modulated electron beam. The stronger cooling was expected in the tail of ion beam and the weaker cooling was performed in the tail of ion beam. The particle in the outside will experience stronger cooling and will be driven back into the centre of ion beam. The ion loss will be decreased and the lifetime will be increased. The intensity of ion beam in the storage ring will be kept and maintain for long time.
	Poster TUP14 [4.160 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-COOL2017-TUP14
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP15	Experimental Demonstration of Electron Cooling with Bunched Electron Beam	61
	L.J. Mao, J. Li, X.M. Ma, M.T. Tang, J.C. Yang, X.D. Yang, H. Zhao, H.W. Zhao IMP/CAS, Lanzhou, People's Republic of China A. Hutton, K. Jordan, T. Powers, R.A. Rimmer, M. Spata, H. Wang, S. Wang, H. Zhang, Y. Zhang JLab, Newport News, Virginia, USA
	Funding: This work was supported by the Hundred Talents Project of the Chinese Academy of Sciences and National Natural Science Foundation of China (Nos. 11575264, 11475235, 11375245) Electron cooling at high energy is presently considered for several ion colliders, in order to achieve high luminosities by enabling a significant reduction of emittance of hadron beams. Electron beam at cooling channel in a few to tens MeV can be accelerated by a RF/SRF linac, and thus using bunched electrons to cool bunched ions. To study such cooling process, the DC electron gun of EC35 cooler was modified by pulsing the grid voltage, by which a 0.5-3.5 us of electron bunch length with a repetition frequency of less than 250 kHz was obtained. The first experiment demonstrated cooling coasting and bunched ion beam by a bunched electron beam was carried out at the storage ring CSRm at IMP. A preliminary data analysis has indicted the bunch length shrinkage and the momentum spread reduction of bunched 12C+6 ion beam. A longitudinal grouping effect of coasting ion beam by the electron bunch has also observed. In this paper, we will present the experiment result and its preliminary comparison to the simulation modeling.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-COOL2017-TUP15
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]
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP19	Status Report about the HV Power Supply and its Test-bench for the HESR Electron Cooler
	I. Alexander, W. Klag IKP, Mainz, Germany K. Aulenbacher, J. Dietrich HIM, Mainz, Germany M.I. Bryzgunov, V.V. Parkhomchuk, V.B. Reva BINP SB RAS, Novosibirsk, Russia
	For an effective cooling at HESR electron energies between 2 MeV and 8 MeV are needed and continuous magnetic beam guidance from the gun to the collector is indispensable. In order to provide the necessary power for the magnet coils, several gas turbines are placed at different electrical potentials. The turbines can deliver a power of 5 kW and are operated with N2. The HV potentials are created by stacking power supplies (PS) that can produce a voltage of 600 kV. The group around V. V. Parkhomchuk at BINP has developed a prototype of the PS. Tests and improvements are ongoing until end of this year. As soon as the PS arrives at the HIM in Mainz, it will be assembled in a pressure vessel to ensure full operation capability. Various future projects could be realized. First, an electron gun could be attached to the PS to characterize different properties by electron beam. Secondly, an additional PS could be installed to increase the electron energy to 1.2 MeV. Thirdly, a gun and a collector could be attached to the PS and a magnetic structure for the beam recirculation could be mounted to demonstrate the feasibility of an electron cooler with the developed equipment.
	Poster TUP19 [2.078 MB]
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

TUP01

Beam Tracking Studies of Electron Cooling in ELENA

J. Resta-López, J.R. Hunt, B. Veglia, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom

The Extra Low ENergy Antiproton storage ring (ELENA), which is a new small synchrotron currently being commissioned at CERN, will further decelerate antiprotons from the Antiproton Decelerator (AD) from 5.3 MeV to energies as low as 100 keV and provide high quality beams for antimatter experiments. At such unprecedented low energy, it is important to evaluate the long term beam stability. To provide a consistent explanation of the different physical effects acting on the beam, multi-particle and multi-turn tracking simulations have been performed in the ELENA ring, including electron cooling and different scattering effects under realistic assumptions. The effect of several imperfections in the electron cooling process is also analysed. The aim is to make a comparison with measurements, thus obtaining a full characterisation of the beam evolution in ELENA.

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP02

Emittance Measurement of Cooled Beams

J. Resta-López, J.R. Hunt, B. Veglia, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Precise emittance measurements are essential to guarantee optimum beam control and performance in all kind of accelerator machines. Amongst them, ultra-low energy antiproton and ion facilities, where beam cooling is essential, are not an exception. In these machines, the emittance reconstruction techniques have to face several challenges, e.g. asymmetric beams, long beam profile tails, diffusion and space charge effects. In addition, likely in a strongly cooled beam there will appear a high correlation between momentum offset and transverse emittance. In this contribution, we investigate effective reconstruction algorithms based in scraping techniques in presence of the above effects. Simulation results are presented for the case of the Extra Low ENergy Antiproton storage ring (ELENA), which is currently being commissioned at CERN.

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP04

Muon Intensity Increase by Wedge Absorbers for low-E Muon Experiments

32

D.V. Neuffer, J. Bradley, D. Stratakis
Fermilab, Batavia, Illinois, USA

Low energy muon experiments such as mu2e and g-2 have a limited energy spread acceptance. Following techniques developed in muon cooling studies and the MICE experiment, the number of muons within the desired energy spread can be increased by the matched use of wedge absorbers. More generally, the phase space of muon beams can be manipulated by absorbers in beam transport lines. Applications with simulation results are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-COOL2017-TUP04

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP05

Towards Laser Cooling of Relativistic ¹⁶O⁵⁺ Ion Beams at the CSRe

H.B. Wang, B. Hai, Z. Huang, J. Li, X.N. Li, X. Ma, L.J. Mao, R.S. Mao, W.Q. Wen, J.X. Wu, J.C. Yang, Y.J. Yuan, D. Zhang, D. Zhao
IMP/CAS, Lanzhou, People's Republic of China
M.H. Bussmann
HZDR, Dresden, Germany
D.F.A. Winters
GSI, Darmstadt, Germany

Laser cooling is one of the most promising techniques to achieve high phase-space densities or even crystalline beams for relativistic heavy ion beams at storage rings [*]. In addition, precision laser spectroscopy of relevant transitions in highly charged ions can also be performed simultaneously during the laser cooling experiments [**]. In the storage ring CSRe at IMP, a new laser cooling experiment for Li-like ¹⁶O⁵⁺ ion beams is currently being prepared and will be carried out at the end of the year 2017 under the Laser-cooling Collaboration. During the experiment, a CW laser with a wavelength of 220 nm will be used to cool the ¹⁶O⁵⁺ ion beams with an energy of 280 MeV/u. The ¹⁶O⁵⁺ ion beams will be the highest charge state and highest energy ions ever used for laser cooling at the storage rings. In the experiment, the longitudinally dynamics of ultra-cold ion beams will be investigate systematically towards the transition of the space charge dominated regime. Precision laser spectroscopy of ¹⁶O⁵⁺ ions for measuring the transition energy of 2s1/2'2p1/2 and 2s1/2'2p3/2 is foreseen.
[*] U. Schramm et al., Progress in Particle and Nuclear Physics, 53 (2004) 583-677.
[**] U. Schramm et al., Hyperfine Interactions 162(1) (2005), 181-188

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

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)

TUP07

Secondary Electron and Photon Measurements at the HIM Electron Cooler Test Set-Up

Th. Beiser
IKP, Mainz, Germany
K. Aulenbacher, M.W. Bruker, T. Weilbach
HIM, Mainz, Germany

A low-energy test set-up for the measurement and optimisation of secondary electron currents from the collector in electron coolers is presented. A variable-field Wien filter and current-measuring aperture plates grant insight into the trajectory and energy distribution of the secondary particles. Photons emitted by residual gas ions trapped inside the electromagnetic potential of the electron beam can be used to measure the location of the beam. The exact composition of those ions, the optical spectrum of said photons, and the possibility of related beam diagnostics is a subject of ongoing research.

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP08

Preliminary Design of Electron Target for SRing at HIAF

40

J. Li, Z. Huang, L.J. Mao, M.T. Tang, S. X. Wang, J.C. Yang, X.D. Yang, H. Zhao, L.X. Zhao
IMP/CAS, Lanzhou, People's Republic of China

A 13 Tm multifunction storage ring dedicated to nucleon and atomic experiment research - the SRing (Spectrometry Ring) is a significant part of the new heavy-ion research complex - HIAF (High Intensity heavy ion Accelerator Facility). In additional to an electron cooler and a gas internal target planned at the SRing, a beam of low temperature electron is also required to collide with the storage beam and to cool the decelerated ion beam at low energy. A magnetic adiabatic expansion is proposed to attain a low temperature by applying a 1.2 T longitudinal magnetic field upon the thermionic cathode at the electron gun. In this paper, preliminary design of the electron target is introduced.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-COOL2017-TUP08

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP09

Project of High-Voltage System with Fast Changing Potential for DR Experiment

44

V.B. Reva, A.P. Denisov, V.V. Parkhomchuk, A.A. Putmakov, D.N. Skorobogatov
BINP SB RAS, Novosibirsk, Russia
J. Li, X. Ma, L.J. Mao
IMP/CAS, Lanzhou, People's Republic of China

Funding: The reported study was partially funded by RFBR 16-52-53016.
A storage ring equipped with an electron cooler is an ideal platform for dielectronic recombination (DR)experiments. In order to fulfill the requirement of DR measurements the system of the precision control of the relative energy between the ion beam and the electron beam should be installed in the electron cooler device. This report describes the project of such system that is designed with section approach like COSY electron cooler. Each section consist of the section of cascade transformer and two power supplies for low and fast detuning of potential of high-voltage terminal. This project can be used in CSRe and future HIAF storage rings.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-COOL2017-TUP09

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP10

Electron Cooling Simulation and Benchmarks

A. Latina, N. Biancacci
CERN, Geneva, Switzerland

Electron Cooling is a method of damping betratron oscillations of heavy particles, like protons, antiprotons, and ions, through the interaction with cold electrons at small relative velocity. A detailed simulation of the Electron Cooling process has been created using a hybrid kinetic model, where the full 6d phase space of a multi-particle beam is immersed in a fluid plasma of electrons. This simulation has been implemented in the tracking code RF-Track, with the aim of exploring the performance of electron coolers in presence of realistic imperfections. Simulations results, and benchmarks against experimental data measured at CERN at LEIR, are presented and discussed in this poster.

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP11

The Interaction Between Electrons and Ions in Comoving and Static Electron Columns

47

V.A. Britten, M. Droba, O. Meusel, H. Podlech, A. Schempp, K. Schulte
IAP, Frankfurt am Main, Germany

The interaction between electrons and positive ion beams and its application in accelerator physics are investigated. A space charge lens named Gabor lens was developed which confines electrons in a static column by external fields. The confined electrons are used for focusing and may support space charge compensation. In this structure the relative velocity between the ions and the electrons is maximal and corresponds to the beam velocity. An electron lens as at the Tevatron* is operated with a lower relative velocity in order to compensate the beam, to clean the beam abort gap or to excite the beam for beam dynamics measurements. In comparison electron cooling needs the same velocity of the ion and the electron beam. The following study contains the superposition of electric and magnetic self-fields and their impact on the density distribution of the ion beam and of the electron beam. Recombinations and ionisations are neglected. This is the beginning of an interface between these topics to find differences and similarities of the interaction between ions and electrons with different relative velocities. This may open up opportunities e.g. for the diagnostics of particle beams.
* Shiltsev, Vladimir, et al. "Tevatron electron lenses: Design and operation." Physical Review Special Topics-Accelerators and Beams 11.10 (2008): 103501.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-COOL2017-TUP11

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP12

Simulation of Low Enery Ion Beam Cooling With Pulsed Electron Beam on CSRm

50

H. Zhao, J. Li, L.J. Maopresenter, M.T. Tang, J.C. Yang, X.D. Yang
IMP/CAS, Lanzhou, People's Republic of China

The pulsed electron beam can be applied to high ener-gy beam cooling and the researches of ion-electron inter-action in the future. In this paper, we studied the pulsed e-beam cooling effects on coasting and bunched ion beam by simulation code which is based on the theory of elec-tron cooling, IBS and space charge effect etc. In the simu-lation, a rectangular distribution of electron beam was applied to 7 MeV/u 12C⁶⁺ ion beam on CSRm. It is found that the coasting ion beam was bunched by the pulsed e-beam and the rising and falling region of electron beam current play an important role for the bunching effect, and similar phenomenon was found for the bunched ion beam. In addition, the analyses of these phenomena in simulation were discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-COOL2017-TUP12

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP13

Calculations of the Gun and Collector for Electron Cooling Systems of HIAF

54

M.T. Tang, J. Li, H.J. Lu, X.M. Ma, L.J. Mao, T.L. Yan, X.D. Yang, H. Zhao, L.X. Zhao
IMP/CAS, Lanzhou, People's Republic of China
A.V. Ivanov
BINP SB RAS, Novosibirsk, Russia

Two electron coolers are designed for the new project HIAF, one cooler with the highest energy 50keV is for the booster ring (BRing) to decreasing the transverse emittance of injected beams and another one with the highest energy 450keV is for the high precision Spec-trometer Ring (SRing). In this paper the results of the gun and collector simulation for these two electron coolers are presented. After optimization, the gun can produce 2A profile variable electron beam. The one time collecting efficiency is higher than 99.99%. The results of electron motions in toroid calculated by a numerical method are also summarized in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-COOL2017-TUP13

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP14

Investigation on the Suppression of Intrabeam Scattering in the High Intensity Heavy Ion Beam with the help of Longitudinal Multi-bunch Chain of Electron

58

X.D. Yang, J. Li, X.M. Ma, L.J. Mao, M.T. Tang, T.L. Yan, H. Zhao
IMP/CAS, Lanzhou, People's Republic of China

Intrabeam scattering is the main reason of degradation of the beam brightness and shortening of brightness lifetime in the collider, light source and storage ring. The intrabeam scattering presents dissimilar influence in the different facilities. Electron cooling was chose to suppress the effect of intrabeam scattering, another unexpected effect happened during the cooling. The distribution of ion beam quickly deviates from the initial Gaussian type, form a denser core and long tail. The ions standing in the tail of beam will loss soon due to large amplitude. This solution will focus on the investigation on the suppression of intrabeam scattering in the high intensity heavy ion beam in the storage ring with the help of longitudinally modulated electron beam. The stronger cooling was expected in the tail of ion beam and the weaker cooling was performed in the tail of ion beam. The particle in the outside will experience stronger cooling and will be driven back into the centre of ion beam. The ion loss will be decreased and the lifetime will be increased. The intensity of ion beam in the storage ring will be kept and maintain for long time.

Poster TUP14 [4.160 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-COOL2017-TUP14

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP15

Experimental Demonstration of Electron Cooling with Bunched Electron Beam

61

L.J. Mao, J. Li, X.M. Ma, M.T. Tang, J.C. Yang, X.D. Yang, H. Zhao, H.W. Zhao
IMP/CAS, Lanzhou, People's Republic of China
A. Hutton, K. Jordan, T. Powers, R.A. Rimmer, M. Spata, H. Wang, S. Wang, H. Zhang, Y. Zhang
JLab, Newport News, Virginia, USA

Funding: This work was supported by the Hundred Talents Project of the Chinese Academy of Sciences and National Natural Science Foundation of China (Nos. 11575264, 11475235, 11375245)
Electron cooling at high energy is presently considered for several ion colliders, in order to achieve high luminosities by enabling a significant reduction of emittance of hadron beams. Electron beam at cooling channel in a few to tens MeV can be accelerated by a RF/SRF linac, and thus using bunched electrons to cool bunched ions. To study such cooling process, the DC electron gun of EC35 cooler was modified by pulsing the grid voltage, by which a 0.5-3.5 us of electron bunch length with a repetition frequency of less than 250 kHz was obtained. The first experiment demonstrated cooling coasting and bunched ion beam by a bunched electron beam was carried out at the storage ring CSRm at IMP. A preliminary data analysis has indicted the bunch length shrinkage and the momentum spread reduction of bunched 12C+6 ion beam. A longitudinal grouping effect of coasting ion beam by the electron bunch has also observed. In this paper, we will present the experiment result and its preliminary comparison to the simulation modeling.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-COOL2017-TUP15

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]

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP19

Status Report about the HV Power Supply and its Test-bench for the HESR Electron Cooler

I. Alexander, W. Klag
IKP, Mainz, Germany
K. Aulenbacher, J. Dietrich
HIM, Mainz, Germany
M.I. Bryzgunov, V.V. Parkhomchuk, V.B. Reva
BINP SB RAS, Novosibirsk, Russia

For an effective cooling at HESR electron energies between 2 MeV and 8 MeV are needed and continuous magnetic beam guidance from the gun to the collector is indispensable. In order to provide the necessary power for the magnet coils, several gas turbines are placed at different electrical potentials. The turbines can deliver a power of 5 kW and are operated with N2. The HV potentials are created by stacking power supplies (PS) that can produce a voltage of 600 kV. The group around V. V. Parkhomchuk at BINP has developed a prototype of the PS. Tests and improvements are ongoing until end of this year. As soon as the PS arrives at the HIM in Mainz, it will be assembled in a pressure vessel to ensure full operation capability. Various future projects could be realized. First, an electron gun could be attached to the PS to characterize different properties by electron beam. Secondly, an additional PS could be installed to increase the electron energy to 1.2 MeV. Thirdly, a gun and a collector could be attached to the PS and a magnetic structure for the beam recirculation could be mounted to demonstrate the feasibility of an electron cooler with the developed equipment.

Poster TUP19 [2.078 MB]

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)