Speaker
Mr
Marc Tippmann
(Technische Universität München)
Description
LENA (Low Energy Neutrino Astronomy) is a next-generation liquid-scintillator neutrino detector with 50kton 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.
Furthermore, a prototype of an Optical Module for the LENA detector has been developed, consisting of pressure-resistant housing containing a PMT, a light concentrator (LC), a mu-metal shielding, a voltage divider and an inactive buffer liquid (LAB) shielding the detector from the PMT's radioactivity. To determine the optimum LC shape Monte Carlo studies using a full optical model of the detector were carried through. The reflectance of potential LC materials was measured and their compatibility with LAB was tested using artificial ageing. Finally, FEM pressure simulations were performed for various designs of the pressure encapsulation to ascertain the compliance with the required maximum pressure of 1.2MPa. The results are presented here for the first time.
- For the LAGUNA-LENA working group -
Primary author
Mr
Marc Tippmann
(Technische Universität München)
Co-authors
Dominikus Hellgartner
(Technische Universität München)
German Beischler
(Technische Universität München)
Jean-Côme Lanfranchi
(Technische Universität München)
Lothar Oberauer
(Technische Universität München)
Max Knötig
(ETH Zürich)
Randolph Möllenberg
(Technische Universität München)
