Regensburg 2013 – wissenschaftliches Programm
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ST: Fachverband Strahlen- und Medizinphysik
ST 6: Advances in Radiation Therapy I
ST 6.4: Vortrag
Donnerstag, 14. März 2013, 16:00–16:20, H41
New approaches for a time- and position-resolved detector for positron annihilation spectroscopy at PLEPS — •Ulrich Ackermann1, Werner Egger1, Peter Sperr1, Benjamin Löwe1, Luca Ravelli1, Gottfried Kögel1, Günther Dollinger1, and Ottmar Jagutzki2 — 1Universität der Bundeswehr München, LRT2 — 2Universität Frankfurt, RoentDek GmbH
The pulsed low energy positron system PLEPS at NEPOMUC at the FRM II is a tool for depth resolved positron lifetime measurements. Besides positron lifetime measurements 2D-AMOC (two dimensional age momentum correlation) experiments are also possible. 2D-AMOC provides in coincidence the lifetime of the positron and the longitudinal momentum distribution of the annihilating electron.
It would be of great scientific concern to measure simultaneously the entire 3D-momentum distribution of the annihilating electron and the corresponding lifetime of the positron (4D-AMOC).
To perform 4D-AMOC measurements, a time and spatially resolving detector with a time resolution of about 100 ps (FWHM) and a spatial resolution of circa 2 mm over an area of about 12 cm2 is required in coincidence with a pixelated Ge-detector and currently under development at our institute. It is intended to use a MCP-based UV-light detector with two MCP-stages coupled to a BaF2 scintillator. To achieve the spatial resolution the centroid information of the photoelectron-cloud is detected with a position sensitive anode installed outside the housing of the MCP detector. As an alternative to a MCP-based detector, silicon photomultipliers are also envisaged.