Mainz 2017 – scientific programme

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MS: Fachverband Massenspektrometrie

MS 7: Poster

MS 7.10: Poster

Wednesday, March 8, 2017, 17:00–19:00, P OG1

A Bragg curve detector for AMS purposes at Cologne AMS — •Gregor Zitzer, Alfred Dewald, Stefan Heinze, Claus Müller-Gatermann, Alexander Stolz, Gereon Hackenberg, Markus Schiffer, and Richard Altenkirch — Institut für Kernphysik, Universität zu Köln

A Bragg curve ionisation chamber has been designed and built for AMS studies at CologneAMS based on the ideas of the Brazilian Bragg curve detector [1], where a NEC accelerator tube module is used for housing the isobutane detector gas. Various detector gases, pressures and axial electrical fields have been tested with alpha particles emitted from a Pu-239, Am-241 and Cm-244 source. In contrast to the normally used analog electronics, with long and short shaping times, the preamplifier pulses are directly fed into a CAEN DT5724 digitizer which digitally processes and analyses the signals in respect of the two corresponding shaping times.

Also in-beam tests were performed with C-14, Al-26 and F-19 in the energy range of 25 - 45 MeV. For C-14 resolutions of 0.4 % fwhm and 2.5 % fwhm, for the total energy and Bragg peak signal, respectively, were obtained.

Finally we present a direct comparison of a standard multi-anode ionisation chamber with the Bragg detector for Cr-54, Fe-54 and Fe-58, Ni-58 beams, which are of special interest for our upcoming AMS program.

[1] G.M. Santos et al., Nucl. Instr. and Meth. in Phys. Res. B 172 (2000) 310-315