BIW2012 - List of Authors (Forck, P.)

Paper

Title

Page

Pilot Studies on Optical Transition Radiation Imaging of Non-relativistic Ions at GSI

130

B. Walasek-Höhne, C.A. Andre, F. Becker, P. Forck, A. Reiter, M. Schwickert
GSI, Darmstadt, Germany
A.H. Lumpkin
Fermilab, Batavia, USA

For relativistic particles optical transition radiation (OTR) is a well established method of transverse profile monitoring. Within a pilot experiment the applicability of OTR even for non-relativistic heavy ions was evaluated for the first time using an uranium beam of 11.4 MeV/u (corresponding to β=0.15) of different charge states. This study aimed to find a thermally stable OTR target for highly-ionizing heavy-ions and to detect reliable transverse profiles, taking advantage of high particle charge q. The exact gating feature of an image-intensified CCD camera was used to select the prompt OTR signal versus any background sources with a longer emission time constant like e.g. blackbody radiation. To test the q-dependence of the light yield, a moveable stripping foil upstream of the target was installed to increase the mean charge. During initial tests, a stainless steel target proved superior thermal behaviour and q2 dependence was observed. Profile comparison with SEM-Grid data as well as the analysis of spectroscopic measurements will be presented.

Slides TUCP03 [6.112 MB]

TUPG022

Transverse Beam Profile Monitoring using Scintillation Screens for High Energy Ion Beams

183

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

The systematic studies of transverse profile measurement were carried out with scintillation screens such as single crystals (CsI:Tl, YAG:Ce), powder screens (P43, P46), ceramics (Al2O3, Al2O3:Cr, Y and Mg doped ZrO2), Ce doped (0.3%) and undoped glasses (Herasil). Different ion beams like C, Ne, Ta, and U accelerated to energy of 300 MeV/u were extracted from the heavy ion synchrotron at GSI within 0.3 s for intensities from 10⁴ to 10⁹ particles per pulse. The image of each beam pulse was recorded by a CCD camera and individually evaluated. The recorded image profiles show a reproducible dependence on scintillation screen. A difference in image width up to 50% is noticed between CsI:Tl and Herasil. The detailed investigation shows that the powder screens P43 and P46, ceramics Al2O3 and Al2O3:Cr reproduce the beam width within a difference of ± 4% for all intensities. The light yield from the screens scales linearly over 5 orders of magnitude of particle intensity. The light yield per energy deposition by a single ion was calculated for different ion beams. This normalized light yield is a factor of 2 higher for Carbon ions compared to Uranium.

TUPG042

High Intensity Effects on Betatron Tune at GSI SIS-18

219

R. Singh, O. Chorniy, P. Forck, R. Haseitl, W. Kaufmann, P. Kowina, K. Lang
GSI, Darmstadt, Germany
T. Weiland
TEMF, TU Darmstadt, Darmstadt, Germany

Funding: This work is supported by DITANET (novel DIagnostic Techniques for future particle Accelerators: A Marie Curie Initial Training NETwork),Project Number ITN-2008-215080
The tune measurement system (TOPOS) at GSI SIS-18 consists of, a band limited noise exciter which excites coherent betatron oscillations in the bunched beam; Fast ADCs to digitize the BPM signals at 125 MSa/s and FPGAs to calculate position from the digitized BPM signals. Baseband tune is thus determined by Fourier transformation of the individual bunch position data. Several tune measurement campaigns were performed with U⁷³⁺ and Ar¹⁸⁺ ion beam at highest achievable intensities of 2x10⁹ and 2.5x10¹⁰ respectively using TOPOS. The goal of these measurements was to understand the high current effects on the tune spectra. Substantial modification of the tune spectra were observed and attributed to the bunch head tail oscillations after further investigations. Coherent tune shift in dependence of beam intensity were also measured. This contribution reports on the modified tune spectra, corresponding space charge effects and further experimental details.

Paper	Title	Page
TUCP03	Pilot Studies on Optical Transition Radiation Imaging of Non-relativistic Ions at GSI	130
	B. Walasek-Höhne, C.A. Andre, F. Becker, P. Forck, A. Reiter, M. Schwickert GSI, Darmstadt, Germany A.H. Lumpkin Fermilab, Batavia, USA
	For relativistic particles optical transition radiation (OTR) is a well established method of transverse profile monitoring. Within a pilot experiment the applicability of OTR even for non-relativistic heavy ions was evaluated for the first time using an uranium beam of 11.4 MeV/u (corresponding to β=0.15) of different charge states. This study aimed to find a thermally stable OTR target for highly-ionizing heavy-ions and to detect reliable transverse profiles, taking advantage of high particle charge q. The exact gating feature of an image-intensified CCD camera was used to select the prompt OTR signal versus any background sources with a longer emission time constant like e.g. blackbody radiation. To test the q-dependence of the light yield, a moveable stripping foil upstream of the target was installed to increase the mean charge. During initial tests, a stainless steel target proved superior thermal behaviour and q2 dependence was observed. Profile comparison with SEM-Grid data as well as the analysis of spectroscopic measurements will be presented.
	Slides TUCP03 [6.112 MB]

TUPG022	Transverse Beam Profile Monitoring using Scintillation Screens for High Energy Ion Beams	183
	K. Renuka, W. Ensinger TU Darmstadt, Darmstadt, Germany C.A. Andre, F. Becker, P. Forck, R. Haseitl, A. Reiter, B. Walasek-Höhne GSI, Darmstadt, Germany
	The systematic studies of transverse profile measurement were carried out with scintillation screens such as single crystals (CsI:Tl, YAG:Ce), powder screens (P43, P46), ceramics (Al2O3, Al2O3:Cr, Y and Mg doped ZrO2), Ce doped (0.3%) and undoped glasses (Herasil). Different ion beams like C, Ne, Ta, and U accelerated to energy of 300 MeV/u were extracted from the heavy ion synchrotron at GSI within 0.3 s for intensities from 10⁴ to 10⁹ particles per pulse. The image of each beam pulse was recorded by a CCD camera and individually evaluated. The recorded image profiles show a reproducible dependence on scintillation screen. A difference in image width up to 50% is noticed between CsI:Tl and Herasil. The detailed investigation shows that the powder screens P43 and P46, ceramics Al2O3 and Al2O3:Cr reproduce the beam width within a difference of ± 4% for all intensities. The light yield from the screens scales linearly over 5 orders of magnitude of particle intensity. The light yield per energy deposition by a single ion was calculated for different ion beams. This normalized light yield is a factor of 2 higher for Carbon ions compared to Uranium.

TUPG042	High Intensity Effects on Betatron Tune at GSI SIS-18	219
	R. Singh, O. Chorniy, P. Forck, R. Haseitl, W. Kaufmann, P. Kowina, K. Lang GSI, Darmstadt, Germany T. Weiland TEMF, TU Darmstadt, Darmstadt, Germany
	Funding: This work is supported by DITANET (novel DIagnostic Techniques for future particle Accelerators: A Marie Curie Initial Training NETwork),Project Number ITN-2008-215080 The tune measurement system (TOPOS) at GSI SIS-18 consists of, a band limited noise exciter which excites coherent betatron oscillations in the bunched beam; Fast ADCs to digitize the BPM signals at 125 MSa/s and FPGAs to calculate position from the digitized BPM signals. Baseband tune is thus determined by Fourier transformation of the individual bunch position data. Several tune measurement campaigns were performed with U⁷³⁺ and Ar¹⁸⁺ ion beam at highest achievable intensities of 2x10⁹ and 2.5x10¹⁰ respectively using TOPOS. The goal of these measurements was to understand the high current effects on the tune spectra. Substantial modification of the tune spectra were observed and attributed to the bunch head tail oscillations after further investigations. Coherent tune shift in dependence of beam intensity were also measured. This contribution reports on the modified tune spectra, corresponding space charge effects and further experimental details.