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HK: Fachverband Physik der Hadronen und Kerne
HK 37: Instrumentation und Anwendungen I
HK 37.6: Talk
Thursday, March 13, 2008, 18:00–18:15, 2C
Performance study of a time-of-flight detector for Isochronous Mass Spectrometry — •Benjamin Fabian1,2, Fritz Bosch2, Timo Dickel1, Hans Geissel1,2, Christophor Kozhuharov2, Ronja Knoebel2, Natalia Kuzminchuk1,2, Sergey Litvinov2, Yuri Litvinov2, Martin Petrick1, Wolfgang Plass1, Christoph Scheidenberger1,2, Baohua Sun2, Martin Winkler2, and Helmut Weick2 — 1II. Physikalisches Institut, Gie{\ss}en, Germany — 2GSI, Darmstadt, Germany
Isochronous Mass Spectrometry as performed at the FRS-ESR facility at GSI can be used to measure masses of exotic nuclei with lifetimes as short as tens of microseconds. For the measurement of the revolution frequencies for a few ions, a time-of-flight detector is used. Secondary electrons released from a thin CsI coated carbon foil at every passage of the ion through the detector are transported to micro-channel-plates (MCP) by electric and magnetic fields. In order to increase the detection efficiency and the timing characteristics, offline and online experiments have been performed. The experimental results have been compared to simulations. Clear evidence for improved detection efficiency at different magnet field have been found. All stages in the detection process from the creation of secondary electrons, their transport to the MCP to the detection in MCPs have been investigated, The comparison shows that the only weak point of the measurement method is the high count rate required. This knowledge can now be used for the developement of a TOF detector for IMS at the CR at FAIR.