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AbstractAbstract
[en] Within the framework of the FAIR-project (Facility for Antiproton and Ion Research) at GSI (Helmholtz Center for Heavy Ion Research), high intensity beams from protons to uranium ions with kinetic energies up to 30 AGeV are foreseen. Present GSI-accelerators like the UNILAC and the Heavy Ion Synchrotron (SIS-18) with a magnetic rigidity of 18 Tm will be used as injectors for the future synchrotron (SIS-100). Their beam current will be increased by up to two orders of magnitude. An accurate beam position and beam profile measurement is mandatory for a safe operation of transport sections, in particular in front of production targets (Fragment Separator (FRS)-target, anti p-production-target and Warm Dense Matter (WDM)-targets). Conventional intercepting profile monitors will not withstand the thermal stress of intensive ion beams, particularly for low energy applications or focused beams. For transverse profile determination a non-intercepting Beam Induced Fluorescence (BIF)-monitor was developed, working with residual gas. The BIF-monitor exploits fluorescence light emitted by residual gas molecules after atomic collisions with beam ions. Fluorescence-images were recorded with an image-intensified camera system, and beam profiles were obtained by projecting these images. Within the scope of this dissertation the following topics have been investigated: The photon yield, profile shape and background contribution were determined for different ion species (H"+, S"6"+, Ar"1"8"+, K"+, Ni"9"+, Xe"4"8"+, Ta"2"4"+, Au"6"5"+, U"7"3"+), beam energies (7.7 AkeV-750 AMeV), gas pressures (10"-"6-3 mbar) and gas species (N_2, He, Ne, Ar, Kr, Xe). Applying an imaging spectrograph and narrowband 10 nm interference filters, the spectral response was mapped and associated with the corresponding gas transitions. Spectrally resolved beam profiles were also obtained form the spectrographic images. Major results are the light yield showing a linear dependence on the gas-pressure for constant profile width and as well as the light yield being proportional to the differential energy loss. For nitrogen, spectral investigation shows a four times higher light yield compared to rare gas species, normalized with respect to the differential energy loss. Helium is the only rare gas that shows broadened beam profiles. All other rare gases and nitrogen show reasonable beam profiles that correspond well with each other. Furthermore the dose-distribution in a cave for beam energies ≥ 100 AMeV was measured and simulated in order to develop a shielding concept that protects the camera system against radiation damage. According to simulations the neutron dose decreases by 94 % in the center of a 1 m"3 concrete cube. Possible profile distortions due to effects like momentum transfer, gas dynamics and the electrical field of the ion beam are discussed. Technical improvements are presented.
Original Title
Zerstoerungsfreie Profilmessung intensiver Schwerionenstrahlen
Primary Subject
Source
8 Feb 2010; 149 p; Available from: http://tuprints.ulb.tu-darmstadt.de/2332/5/Dissertation_FB_print.pdf; Diss. (Dr.rer.nat.)
Record Type
Miscellaneous
Literature Type
Thesis/Dissertation
Country of publication
BEAM MONITORING, BEAM MONITORS, BEAM PROFILES, FLUORESCENCE, GEV RANGE, ION BEAMS, ION-ATOM COLLISIONS, ION-MOLECULE COLLISIONS, KEV RANGE, MEV RANGE 01-10, MEV RANGE 100-1000, MEV RANGE 10-100, MULTICHARGED IONS, NITROGEN, PRESSURE RANGE MICRO PA, PRESSURE RANGE MILLI PA, PRESSURE RANGE NANO PA, PRESSURE RANGE PA, RARE GASES
Reference NumberReference Number
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