DIPAC2011 - List of Authors (Egberts, J.)

Paper

Title

Page

Detailed Experimental Characterization of an Ionization Profile Monitor

547

J. Egberts, P. Abbon, F. Jeanneau, J.-Ph. Mols, T. Papaevangelou
CEA, Gif-sur-Yvette, France
F. Becker, P. Forck, B. Walasek-Höhne
GSI, Darmstadt, Germany
J. Marroncle
CEA/DSM/IRFU, France

Funding: Marie Curie Fellowship by the EU
In the frame of the International Fusion Material Irradiation Facility (IFMIF), a prototype for a non-interceptive transverse beam profile monitor based on residual gas ionization (IPM) has been built and characterized in detail. We present results of test measurements performed at CEA Saclay with 80 keV protons in a cw beam of up to 10 mA and at GSI Darmstadt with pulsed Ca¹⁰⁺, Xe²¹⁺ and U²⁸⁺ beams of up to 1.6 mA at 5 MeV/u. The effects of N₂, and different rare gases in the pressure range from 4•10^-7 mbar to 5•10^-4 mbar have been investigated. The signal was read by different electronic cards, based on linear and logarithmic amplifiers as well as on charge integration. Furthermore the extraction voltage of the IPM-field-box was varied between 0.5 and 5 kV. Beam profiles were investigated with respect to signal intensity and profile shape and were compared to a SEM-grid and a Beam Induced Fluorescence monitor. Profiles of all monitors match nicely for the residual gases with differences in beam width well below 5%. Additional tests on the characteristics of the IPM have been performed and will be presented as well.

Slides WEOA03 [1.964 MB]

MOPD42

μ-loss Detector for IFMIF-EVEDA

146

J. Marroncle, P. Abbon, J. Egberts
CEA/DSM/IRFU, France
M. Pomorski
CEA/DRT/LIST, Gif-sur-Yvette Cedex, France

For the IFMIF-EVEDA project, a prototype accelerator is being built in Europe and installed at Rokkasho (Japan). It is designed to accelerate 125 mA CW Deuteron to 9 MeV. The very high space charge and high power (1.125 MW) of the beam make this accelerator very challenging. For hands-on maintenance requirements, losses must be well less than 1W/m, i.e. 10^-6 of the beam. That is why, in the 5-9 MeV superconducting Linac, beam dynamics physicists search to tune the beam by minimizing the very external part of the halo. The need is thus to be able to measure very tiny beam losses, called μ-losses, at all the focusing magnets. Only neutrons and γ exit from the beam pipe due to the low deuteron beam energy. Thus such beam loss detectors have to be sensitive to neutrons, but rather insensitive for X-rays and γ to decrease their contributions coming from super-conducting cavity emission. They must be radiation hardness qualified, and capable to work at cryogenic temperature. Single CVD diamonds (4×4×0.5 mm³) are studied for these purposes and first results seem to fulfill the requirements up to now.

Paper	Title	Page
WEOA03	Detailed Experimental Characterization of an Ionization Profile Monitor	547
	J. Egberts, P. Abbon, F. Jeanneau, J.-Ph. Mols, T. Papaevangelou CEA, Gif-sur-Yvette, France F. Becker, P. Forck, B. Walasek-Höhne GSI, Darmstadt, Germany J. Marroncle CEA/DSM/IRFU, France
	Funding: Marie Curie Fellowship by the EU In the frame of the International Fusion Material Irradiation Facility (IFMIF), a prototype for a non-interceptive transverse beam profile monitor based on residual gas ionization (IPM) has been built and characterized in detail. We present results of test measurements performed at CEA Saclay with 80 keV protons in a cw beam of up to 10 mA and at GSI Darmstadt with pulsed Ca¹⁰⁺, Xe²¹⁺ and U²⁸⁺ beams of up to 1.6 mA at 5 MeV/u. The effects of N₂, and different rare gases in the pressure range from 4•10^-7 mbar to 5•10^-4 mbar have been investigated. The signal was read by different electronic cards, based on linear and logarithmic amplifiers as well as on charge integration. Furthermore the extraction voltage of the IPM-field-box was varied between 0.5 and 5 kV. Beam profiles were investigated with respect to signal intensity and profile shape and were compared to a SEM-grid and a Beam Induced Fluorescence monitor. Profiles of all monitors match nicely for the residual gases with differences in beam width well below 5%. Additional tests on the characteristics of the IPM have been performed and will be presented as well.
	Slides WEOA03 [1.964 MB]

MOPD42	μ-loss Detector for IFMIF-EVEDA	146
	J. Marroncle, P. Abbon, J. Egberts CEA/DSM/IRFU, France M. Pomorski CEA/DRT/LIST, Gif-sur-Yvette Cedex, France
	For the IFMIF-EVEDA project, a prototype accelerator is being built in Europe and installed at Rokkasho (Japan). It is designed to accelerate 125 mA CW Deuteron to 9 MeV. The very high space charge and high power (1.125 MW) of the beam make this accelerator very challenging. For hands-on maintenance requirements, losses must be well less than 1W/m, i.e. 10^-6 of the beam. That is why, in the 5-9 MeV superconducting Linac, beam dynamics physicists search to tune the beam by minimizing the very external part of the halo. The need is thus to be able to measure very tiny beam losses, called μ-losses, at all the focusing magnets. Only neutrons and γ exit from the beam pipe due to the low deuteron beam energy. Thus such beam loss detectors have to be sensitive to neutrons, but rather insensitive for X-rays and γ to decrease their contributions coming from super-conducting cavity emission. They must be radiation hardness qualified, and capable to work at cryogenic temperature. Single CVD diamonds (4×4×0.5 mm³) are studied for these purposes and first results seem to fulfill the requirements up to now.