IPAC2014 - List of Authors (Bozyk, L.H.J.)

Paper	Title	Page
MOPRI087	Challenges of the Technical Layout of the SIS 100 Extraction System	815
	N. Pyka, L.H.J. Bozyk, U. Kopf, C. Mühle, D. Ondreka, P. Rottländer, P.J. Spiller, St. Wilfert GSI, Darmstadt, Germany A.G. Kalimov St. Petersburg State Polytechnic University, St. Petersburg, Russia
	The FAIR synchrotron SIS100 which is under construction will provide heavy ion and proton beams of high intensity with fast and slow extraction. All extraction devices, including an internal emergency beam dump system, are installed within one straight section. This way, expected systematic beam loss is kept in a relatively small area of the synchrotron. In this area, it is rather challenging to protect components against high radiation fields, to keep XHV conditions, and to allow for maintenance of highly activated components to assure reliable beam operation. In this contribution, the technical measures to fulfill the requirements for the extraction straight section of SIS100 will be presented. These include remote controlled devices to move apart magnet yokes for the purpose of placing beam pipe heater; dedicated star-shaped vacuum chambers with integrated collimators and NEG-panels to reduce pressure bumps due to lost particles behind the electrostatic septa; a high-power multi-stage vertical extraction septum including a variable horizontal deflection.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI087
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MOPRI104	Measurement of Beam Ioniziation Loss in SIS18	864
	L.H.J. Bozyk, P.J. Spiller GSI, Darmstadt, Germany
	In the heavy ion synchrotron SIS18 at GSI an ion catcher system has been installed to provide low desorption surfaces for ionization beam loss to reduce dynamic vacuum effects. Medium charge state heavy ions can change their charge state in collission with residual gas molecules. Those ions are cought by the ion catcher system. The ion catcher blocks are mounted electrically insulated, such that it is possible, to directly measure the electrical current, induced by the incident ions. Changes in vacuum density during the acceleration cycle and also the energy dependent decrease of the cross sections for electron loss and electron capture can be measured by this system. Different ion catcher currents, measured during the operation with U²⁸⁺, and their interpretation are presented. The measurement of ionization beam loss is a valuable tool to benchmark the dynamic vacuum simulations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI104
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MOPRI105	Heavy Ion Induced Desorption Measurements on Cryogenic Targets	867
SUSPSNE045	use link to see paper's listing under its alternate paper code
	Ch. Maurer, D.H.H. Hoffmann TU Darmstadt, Darmstadt, Germany L.H.J. Bozyk, H. Kollmus, Ch. Maurer, P.J. Spiller GSI, Darmstadt, Germany
	Funding: Bundesministerium für Bildung und Forschung FKZ 06DA7031 Heavy-ion impact induced gas desorption is the key process that drives beam intensity limiting dynamic vacuum losses. Minimizing this effect, by providing low desorption yield surfaces, is an important issue for maintaining a stable ultra high vacuum during operation with medium charge state heavy ions. For room temperature targets, investigation shows a scaling of the desorption yield with the beam's near-surface electronic energy loss, i.e. a decrease with increasing energy,. An optimized material for a room temperature ion-catcher has been found. But for the planned superconducting heavy-ion synchrotron SIS100 at the FAIR accelerator complex, the ion catcher system has to work in a cryogenic environment. Desorption measurements with the prototype cryocatcher for SIS100 showed an unexpected energy scaling*, which needs to be explained. Understanding this scaling might lead to a better suited choice of material, resulting in a lower desorption yield. An experimental setup for systematic examination of this scaling is presented. The cryogenic beam-induced desorption yield of several materials at different temperatures is examined. H. Kollmus et al., AIP Conf. Proc. 773, 207 (2005)) E. Mahner et al., Phys. Rev. ST Accel. Beams 14, 050102 (2011) * L.H.J. Bozyk, H. Kollmus, P.J. Spiller, Proc. of IPAC 2012, p. 3239
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI105
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WEOBA01	Status of the FAIR Synchrotron Projects SIS18 Upgrade and SIS100	1857
	P.J. Spiller, R. Balß, A. Bleile, L.H.J. Bozyk, J. Ceballos Velasco, T. Eisel, E.S. Fischer, P. Forck, P. Hülsmann, M. Kauschke, O.K. Kester, H. Klingbeil, H.G. König, H. Kollmus, P. Kowina, A. Krämer, J.P. Meier, A. Mierau, C. Omet, D. Ondreka, N. Pyka, H. Ramakers, P. Schnizer, H. Welker, St. Wilfert GSI, Darmstadt, Germany A. Iluk WRUT, Wrocław, Poland H.G. Khodzhibagiyan JINR, Dubna, Moscow Region, Russia D. Urner FAIR, Darmstadt, Germany
	The upgrade of the existing heavy ion synchrotron SIS18 as booster for the FAIR synchrotron SIS100 has been partly completed. With the achieved technical status, a major increase of the accelerated number of heavy ions could be reached. This progress especially demonstrates the feasibilty of acceleration of medium charge state heavy ions with high intensity and and the succesfull control of dynamic vaccuum effects and correlated charge exchange loss. Two further upgrade measures, the installation of additional MA acceleration cavities and the exchange of the main dipole power converter are in progress. For the FAIR synchrotron SIS100 all major components with long production times have been ordered. With several pre-series components, outstanding technical developments have been completed and the readiness for series production reached. The technical project status will be summarized.
	Slides WEOBA01 [6.107 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEOBA01
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WEPME028	Systematic Measurement of the Pumping Capabilities of Cryogenic Surfaces	2317
SUSPSNE102	use link to see paper's listing under its alternate paper code
	F. Chill, O.K. Kester IAP, Frankfurt am Main, Germany L.H.J. Bozyk, O.K. Kester, P.J. Spiller GSI, Darmstadt, Germany
	The quality of the beam vacuum is crucial for the stable operation of synchrotrons with high intensity heavy ions. Cryogenic surfaces are capable of pumping residual gases by cryocondensation until the saturated vapor pressure (SVP) is reached. Even at LHe temperatures the SVP of hydrogen is too high. If the surface coverage is sufficiently low, residual gas can also be bound by cryosorption, yielding in acceptable low pressures. These pumping capabilities can be described by two parameters, both dependent on surface temperature and coverage: The sticking probability (SP), that is the chance of an impinging gas particle to be bound, and the mean sojourn time (MST) of a particle on the surface. To acquire these parameters, an experimental setup is currently built at GSI. It consists of a cryogenic chamber, cooled by a cold head and a warm part with vacuum diagnostics and gas inlet. It allows monitoring the pumping speed and also the equilibrium pressure of the cryogenic part from which the SP and the MST can be deducted. The results will be used to further improve the accuracy of the dynamic vacuum simulations in cryogenic areas of particle accelerators.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME028
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Challenges of the Technical Layout of the SIS 100 Extraction System

815

N. Pyka, L.H.J. Bozyk, U. Kopf, C. Mühle, D. Ondreka, P. Rottländer, P.J. Spiller, St. Wilfert
GSI, Darmstadt, Germany
A.G. Kalimov
St. Petersburg State Polytechnic University, St. Petersburg, Russia

The FAIR synchrotron SIS100 which is under construction will provide heavy ion and proton beams of high intensity with fast and slow extraction. All extraction devices, including an internal emergency beam dump system, are installed within one straight section. This way, expected systematic beam loss is kept in a relatively small area of the synchrotron. In this area, it is rather challenging to protect components against high radiation fields, to keep XHV conditions, and to allow for maintenance of highly activated components to assure reliable beam operation. In this contribution, the technical measures to fulfill the requirements for the extraction straight section of SIS100 will be presented. These include remote controlled devices to move apart magnet yokes for the purpose of placing beam pipe heater; dedicated star-shaped vacuum chambers with integrated collimators and NEG-panels to reduce pressure bumps due to lost particles behind the electrostatic septa; a high-power multi-stage vertical extraction septum including a variable horizontal deflection.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI087

Export •

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

MOPRI104

Measurement of Beam Ioniziation Loss in SIS18

864

L.H.J. Bozyk, P.J. Spiller
GSI, Darmstadt, Germany

In the heavy ion synchrotron SIS18 at GSI an ion catcher system has been installed to provide low desorption surfaces for ionization beam loss to reduce dynamic vacuum effects. Medium charge state heavy ions can change their charge state in collission with residual gas molecules. Those ions are cought by the ion catcher system. The ion catcher blocks are mounted electrically insulated, such that it is possible, to directly measure the electrical current, induced by the incident ions. Changes in vacuum density during the acceleration cycle and also the energy dependent decrease of the cross sections for electron loss and electron capture can be measured by this system. Different ion catcher currents, measured during the operation with U²⁸⁺, and their interpretation are presented. The measurement of ionization beam loss is a valuable tool to benchmark the dynamic vacuum simulations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI104

Export •

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

MOPRI105

Heavy Ion Induced Desorption Measurements on Cryogenic Targets

867

SUSPSNE045

use link to see paper's listing under its alternate paper code

Ch. Maurer, D.H.H. Hoffmann
TU Darmstadt, Darmstadt, Germany
L.H.J. Bozyk, H. Kollmus, Ch. Maurer, P.J. Spiller
GSI, Darmstadt, Germany

Funding: Bundesministerium für Bildung und Forschung FKZ 06DA7031
Heavy-ion impact induced gas desorption is the key process that drives beam intensity limiting dynamic vacuum losses. Minimizing this effect, by providing low desorption yield surfaces, is an important issue for maintaining a stable ultra high vacuum during operation with medium charge state heavy ions. For room temperature targets, investigation shows a scaling of the desorption yield with the beam's near-surface electronic energy loss, i.e. a decrease with increasing energy*,**. An optimized material for a room temperature ion-catcher has been found. But for the planned superconducting heavy-ion synchrotron SIS100 at the FAIR accelerator complex, the ion catcher system has to work in a cryogenic environment. Desorption measurements with the prototype cryocatcher for SIS100 showed an unexpected energy scaling***, which needs to be explained. Understanding this scaling might lead to a better suited choice of material, resulting in a lower desorption yield. An experimental setup for systematic examination of this scaling is presented. The cryogenic beam-induced desorption yield of several materials at different temperatures is examined.
* H. Kollmus et al., AIP Conf. Proc. 773, 207 (2005))
** E. Mahner et al., Phys. Rev. ST Accel. Beams 14, 050102 (2011)
*** L.H.J. Bozyk, H. Kollmus, P.J. Spiller, Proc. of IPAC 2012, p. 3239

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI105

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WEOBA01

Status of the FAIR Synchrotron Projects SIS18 Upgrade and SIS100

1857

P.J. Spiller, R. Balß, A. Bleile, L.H.J. Bozyk, J. Ceballos Velasco, T. Eisel, E.S. Fischer, P. Forck, P. Hülsmann, M. Kauschke, O.K. Kester, H. Klingbeil, H.G. König, H. Kollmus, P. Kowina, A. Krämer, J.P. Meier, A. Mierau, C. Omet, D. Ondreka, N. Pyka, H. Ramakers, P. Schnizer, H. Welker, St. Wilfert
GSI, Darmstadt, Germany
A. Iluk
WRUT, Wrocław, Poland
H.G. Khodzhibagiyan
JINR, Dubna, Moscow Region, Russia
D. Urner
FAIR, Darmstadt, Germany

The upgrade of the existing heavy ion synchrotron SIS18 as booster for the FAIR synchrotron SIS100 has been partly completed. With the achieved technical status, a major increase of the accelerated number of heavy ions could be reached. This progress especially demonstrates the feasibilty of acceleration of medium charge state heavy ions with high intensity and and the succesfull control of dynamic vaccuum effects and correlated charge exchange loss. Two further upgrade measures, the installation of additional MA acceleration cavities and the exchange of the main dipole power converter are in progress. For the FAIR synchrotron SIS100 all major components with long production times have been ordered. With several pre-series components, outstanding technical developments have been completed and the readiness for series production reached. The technical project status will be summarized.

Slides WEOBA01 [6.107 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEOBA01

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

WEPME028

Systematic Measurement of the Pumping Capabilities of Cryogenic Surfaces

2317

SUSPSNE102

use link to see paper's listing under its alternate paper code

F. Chill, O.K. Kester
IAP, Frankfurt am Main, Germany
L.H.J. Bozyk, O.K. Kester, P.J. Spiller
GSI, Darmstadt, Germany

The quality of the beam vacuum is crucial for the stable operation of synchrotrons with high intensity heavy ions. Cryogenic surfaces are capable of pumping residual gases by cryocondensation until the saturated vapor pressure (SVP) is reached. Even at LHe temperatures the SVP of hydrogen is too high. If the surface coverage is sufficiently low, residual gas can also be bound by cryosorption, yielding in acceptable low pressures. These pumping capabilities can be described by two parameters, both dependent on surface temperature and coverage: The sticking probability (SP), that is the chance of an impinging gas particle to be bound, and the mean sojourn time (MST) of a particle on the surface. To acquire these parameters, an experimental setup is currently built at GSI. It consists of a cryogenic chamber, cooled by a cold head and a warm part with vacuum diagnostics and gas inlet. It allows monitoring the pumping speed and also the equilibrium pressure of the cryogenic part from which the SP and the MST can be deducted. The results will be used to further improve the accuracy of the dynamic vacuum simulations in cryogenic areas of particle accelerators.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME028

Export •

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