https://doi.org/10.1140/epjc/s10052-016-4140-7
Regular Article - Experimental Physics
The performance of the Muon Veto of the Gerda experiment
1
Physikalisches Institut, Eberhard Karls Universität Tübingen, Tübingen, Germany
2
Institute for Nuclear Research of the Russian Academy of Sciences, Moscow, Russia
3
Joint Institute for Nuclear Research, Dubna, Russia
4
maxment GmbH, Heidelberg, Germany
5
Areva, Rome, France
6
Bosch GmbH, Stuttgart, Germany
* e-mail: grabmayr@uni-tuebingen.de
Received:
25
January
2016
Accepted:
12
May
2016
Published online:
25
May
2016
Low background experiments need a suppression of cosmogenically induced events. The Gerda experiment located at Lngs is searching for the 0νββ decay of 76Ge. It is equipped with an active muon veto the main part of which is a water Cherenkov veto with 66 PMTs in the water tank surrounding the Gerda cryostat. With this system 806 live days have been recorded, 491 days were combined muon–germanium data. A muon detection efficiency of εμd = (99.935 ± 0.015)% was found in a Monte Carlo simulation for the muons depositing energy in the germanium detectors. By examining coincident muon–germanium events a rejection efficiency of εμr = (99.2+0.3-0.4) % was found. Without veto condition the muons by themselves would cause a background index of BIµ = (3.16 ± 0.85) × 10-3 cts/(keV·kg·year) at Qββ.
© The Author(s), 2016
