Dresden 2013 – scientific programme

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T: Fachverband Teilchenphysik

T 109: Experimentelle Techniken der Astroteilchenphysik 2

T 109.6: Talk

Monday, March 4, 2013, 18:05–18:20, HSZ-101

Bremsstrahlung and fluorescence in PMTs causing fast afterpulses — •Marc Tippmann, Max Knötig, Simon Appel, German Beischler, Jill Kaindl, Timo Lewke, Quirin Meindl, Randolph Möllenberg, Lothar Oberauer, Patrick Pfahler, Ludwig Prade, Tobias Stempfle, Jürgen Winter, and Vincenz Zimmer — for the LAGUNA-LENA working group — Technische Universität München, Physik Department E15, James Franck Straße, 85748 Garching

LENA (Low Energy Neutrino Astronomy) is a next-generation liquid-scintillator neutrino detector with 50kt target mass. The broad spectrum of physics goals ranging from the sub-MeV to the GeV regime sets high demands on the photosensors. Currently, photomultipliers (PMTs) are the sensor of choice. However, besides detecting photons, they also emit light through bremsstrahlung or fluorescence induced by the electron avalanche in the dynode chain, which can produce further pulses in the same PMT or adjacent sensors.

In order to study these effects and their connection to afterpulses occurring in the PMT, measurements of light emission and fast afterpulses have been carried through in collaboration with the CTA project. Both bremsstrahlung and fluorescence have been observed, with the first also being the origin of a type of fast afterpulses.

This work has been supported by the Max-Planck-Gesellschaft, the Maier-Leibnitz-Laboratorium, the TR 27 ’Neutrinos and Beyond’ and the cluster of excellence ’Origin and Structure of the Universe’.