DIPAC2011 - List of Authors (Reiter, A.)

Paper

Title

Page

Improved Signal Treatment for Capacitive Linac Pick-Ups

128

A. Reiter, C.M. Kleffner, B. Schlitt
GSI, Darmstadt, Germany

Phase probes are a crucial diagnostic tool for pulsed particle beams of linear accelerators. In this contribution we present a simple, but very effective analysis procedure which has been established in various applications during commissioning campaigns of injector linacs for medical facilities. These injectors consist of a 400 keV/u radio-frequency quadrupole followed by a 7 MeV/u inter-digital drift tube linac, both operating at 216.8 MHz. At GSI, the new analysis was recently applied at the HITRAP decelerator, also with promising results. The data analysis exploits the periodic nature of sampling process and bunch signal improving the detector sensitivity and achieving an effective resolution of < 10 ps. If the macro-pulse is sufficiently long, the quality of the data can be improved further by a statistical average of subsequent data blocks acquired within one single macro-pulse. The latter is important for experiments with low beam intensity and low repetition rate like HITRAP where averaging over many macro-pulses is cumbersome.

MOPD53

Scintillation Screen Investigations for High Energy Heavy Ion Beams at GSI

170

P. Forck, C.A. Andre, F. Becker, R. Haseitl, A. Reiter, B. Walasek-Höhne
GSI, Darmstadt, Germany
W. Ensinger, K. Renuka
TU Darmstadt, Darmstadt, Germany

Funding: Funded by the German Ministry of Science (BMBF) under contract No. 06DA9026
Various scintillation screens were irradiated with high energy ion beams as extracted from the GSI synchrotron SIS18. Their imaging properties were studied with the goal to achieve a precise transverse profile determination. Scintillation images were characterized with respect to the light yield and statistical moments of the light distribution i.e. imaged beam width and shape. To study the scintillation properties over a wide range of intensities a 300 MeV/u Uranium ion beam with 10⁴ to 10⁹ particles per pulse was applied. Sensitive scintillators, namely CsI:Tl, YAG:Ce, P43 and Ce-doped glass were investigated for lower beam currents. Ceramics like Al₂O₃, Al₂O₃:Cr, ZrO₂:Y and ZrO₂:Mg as well as Herasil-glass were studied up to the maximum beam currents. For the various screens remarkable differences have been observed, e.g. the recorded profile width varies by nearly a factor of two. The obtained results serve as a basis for an appropriate choice of scintillator materials, which have to cope with the diversity of ion species and intensities at FAIR.

Poster MOPD53 [1.897 MB]

TUPD05

Diagnostic Scheme for the HITRAP Decelerator

311

G. Vorobjev, C.A. Andre, W.A. Barth, E. Berdermann, M.I. Ciobanu, G. Clemente, L.A. Dahl, P. Forck, P. Gerhard, R. Haseitl, F. Herfurth, M. Kaiser, W. Kaufmann, H.J. Kluge, N. Kotovski, C. Kozhuharov, M.T. Maier, W. Quint, A. Reiter, A. Sokolov, T. Stöhlker
GSI, Darmstadt, Germany
O.K. Kester, J. Pfister, U. Ratzinger, A. Schempp
IAP, Frankfurt am Main, Germany

The HITRAP linear decelerator currently being set up at GSI will provide slow, few keV/u highly charged ions for atomic physics experiments. The expected beam intensity is up to 10⁵ ions per shot. To optimize phase and amplitude of the RF systems intensity, bunch length and kinetic energy of the particles need to be monitored. The bunch length that we need to fit is about 2 ns, which is typically measured by capacitive pickups. However, they do not work for the low beam intensities that we face. We investigated the bunch length with a fast CVD diamond detector working in single particle counting mode. Averaging over 8 shots yields a clear, regular picture of the bunched beam. Energy measurements by capacitive pickups are limited by the presence of intense primary and partially decelerated beam and hence make tuning of the IH-structure impossible. The energy of the decelerated fraction of the beam behind the first deceleration cavity was determined to about 10 % accuracy with a permanent dipole magnet combined with a MCP. Better detector calibration should help reaching the required 1%. Design of the detectors as well as the results of the measurements will be presented.

Paper	Title	Page
MOPD35	Improved Signal Treatment for Capacitive Linac Pick-Ups	128
	A. Reiter, C.M. Kleffner, B. Schlitt GSI, Darmstadt, Germany
	Phase probes are a crucial diagnostic tool for pulsed particle beams of linear accelerators. In this contribution we present a simple, but very effective analysis procedure which has been established in various applications during commissioning campaigns of injector linacs for medical facilities. These injectors consist of a 400 keV/u radio-frequency quadrupole followed by a 7 MeV/u inter-digital drift tube linac, both operating at 216.8 MHz. At GSI, the new analysis was recently applied at the HITRAP decelerator, also with promising results. The data analysis exploits the periodic nature of sampling process and bunch signal improving the detector sensitivity and achieving an effective resolution of < 10 ps. If the macro-pulse is sufficiently long, the quality of the data can be improved further by a statistical average of subsequent data blocks acquired within one single macro-pulse. The latter is important for experiments with low beam intensity and low repetition rate like HITRAP where averaging over many macro-pulses is cumbersome.

MOPD53	Scintillation Screen Investigations for High Energy Heavy Ion Beams at GSI	170
	P. Forck, C.A. Andre, F. Becker, R. Haseitl, A. Reiter, B. Walasek-Höhne GSI, Darmstadt, Germany W. Ensinger, K. Renuka TU Darmstadt, Darmstadt, Germany
	Funding: Funded by the German Ministry of Science (BMBF) under contract No. 06DA9026 Various scintillation screens were irradiated with high energy ion beams as extracted from the GSI synchrotron SIS18. Their imaging properties were studied with the goal to achieve a precise transverse profile determination. Scintillation images were characterized with respect to the light yield and statistical moments of the light distribution i.e. imaged beam width and shape. To study the scintillation properties over a wide range of intensities a 300 MeV/u Uranium ion beam with 10⁴ to 10⁹ particles per pulse was applied. Sensitive scintillators, namely CsI:Tl, YAG:Ce, P43 and Ce-doped glass were investigated for lower beam currents. Ceramics like Al₂O₃, Al₂O₃:Cr, ZrO₂:Y and ZrO₂:Mg as well as Herasil-glass were studied up to the maximum beam currents. For the various screens remarkable differences have been observed, e.g. the recorded profile width varies by nearly a factor of two. The obtained results serve as a basis for an appropriate choice of scintillator materials, which have to cope with the diversity of ion species and intensities at FAIR.
	Poster MOPD53 [1.897 MB]

TUPD05	Diagnostic Scheme for the HITRAP Decelerator	311
	G. Vorobjev, C.A. Andre, W.A. Barth, E. Berdermann, M.I. Ciobanu, G. Clemente, L.A. Dahl, P. Forck, P. Gerhard, R. Haseitl, F. Herfurth, M. Kaiser, W. Kaufmann, H.J. Kluge, N. Kotovski, C. Kozhuharov, M.T. Maier, W. Quint, A. Reiter, A. Sokolov, T. Stöhlker GSI, Darmstadt, Germany O.K. Kester, J. Pfister, U. Ratzinger, A. Schempp IAP, Frankfurt am Main, Germany
	The HITRAP linear decelerator currently being set up at GSI will provide slow, few keV/u highly charged ions for atomic physics experiments. The expected beam intensity is up to 10⁵ ions per shot. To optimize phase and amplitude of the RF systems intensity, bunch length and kinetic energy of the particles need to be monitored. The bunch length that we need to fit is about 2 ns, which is typically measured by capacitive pickups. However, they do not work for the low beam intensities that we face. We investigated the bunch length with a fast CVD diamond detector working in single particle counting mode. Averaging over 8 shots yields a clear, regular picture of the bunched beam. Energy measurements by capacitive pickups are limited by the presence of intense primary and partially decelerated beam and hence make tuning of the IH-structure impossible. The energy of the decelerated fraction of the beam behind the first deceleration cavity was determined to about 10 % accuracy with a permanent dipole magnet combined with a MCP. Better detector calibration should help reaching the required 1%. Design of the detectors as well as the results of the measurements will be presented.