Low background experiments need a suppression of cosmogenically induced events. The Gerda experiment located at Lngs is searching for the \(0\nu \beta \beta \) decay of \(^{76}\)Ge. 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 \(\varepsilon _\mathrm{\upmu d}=(99.935\pm 0.015)\) % 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 \(\varepsilon _{\upmu r}=(99.2_{-0.4}^{+0.3})\) % was found. Without veto condition the muons by themselves would cause a background index of \(\text {BI}_{\mu }=(3.16 \pm 0.85)\times 10^{-3}\) \(\mathrm{cts/(keV}\cdot \mathrm{kg}\cdot \mathrm{year)}\) at \(Q_{\beta \beta }\).

The GERDA experiment at LNGS of INFN is equipped with an active muon veto. The main part of the system is a water Cherenkov veto with 66 PMTs in the water tank surrounding the GERDA cryostat. The muon flux recorded by this veto shows a seasonal modulation. Two causes have been identified: (i) secondary muons from the CNGS neutrino beam (2.2%) and (ii) a temperature modulation of the atmosphere (1.4%). A mean cosmic muon rate of 1(mu)(0) = (3.477 +/- 0.002(stat) +/- 0.067(sys)) x 10(-4)/(s center dot m(2)) was found in good agreement with other experiments at LNGS. Combining the present result with those from previous experiments at LNGS the effective temperature coefficient alpha(T,LNGS) is determined to 0.93 +/- 0.03. A fit of the temperature coefficients measured at various underground sites yields a kaon to pion ratio r(k/Pi)of 0.10 +/- 0.03. (C) 2016 Elsevier B.V. All rights reserved.

The GERDA collaboration is performing a search for neutrinoless double beta decay of ^76Ge with the eponymous detector. The experiment has been installed and commissioned at the Laboratori Nazionali del Gran Sasso and has started operation in November 2011. The design, construction and first operational results are described, along with detailed information from the R D phase.

The Gerda collaboration is performing a search for neutrinoless double beta decay of 76 Ge with the eponymous detector. The experiment has been installed and commissioned at the Laboratori Nazionali del Gran Sasso and has started operation in November 2011. The design, construction and first operational results are described, along with detailed information from the R&D phase.

The GERmanium Detector Array, GERDA, (1] is designed to search for neutrinoless double beta (0 nu beta beta) decay of Ge-76. The importance of such a search is emphasized by the evidence of a non-zero neutrino mass from flavour oscillation experiments and by the recent claim [2] based on data of the Heidelberg-Moscow experiment. GERDA will be installed in the Hall A of the Gran Sasso underground Laboratory (LNGS), Italy. The construction of GERDA will start in 2006.

The GERmanium Detector Array, GERDA, is a new experiment designed to examine the neutrinoless double beta decay 0 nu beta beta of (76)Ge which has a lifetime of at least 10(26) years and a single energy deposition of 2039 keV. To reach the goal of 10(-3) background events/(keV kg y), several background reduction techniques like anti-coincidence and pulse shape analysis will be used. Cosmic muons can produce background in form of particles and radioactivity. To reject them, two independent detector systems will be integrated in GERDA. One of these is a Cherenkov muon veto detector, that uses the water tank around the cryostat in which the crystals will be operated. It is equipped with 66 photomultipliers (PMTs) with 8 in. diameter.The PMT distribution was found via extensive Monte Carlo studies to reach the highest efficiencies for dangerous muons (these are muons that cause an energy deposition of around 2 MeV in the germanium detectors), even though the PMTs cover less than 0.1% of the water tank surface.High efficiencies depend strongly on the amount of detected photons. For this, as many surfaces as possible will be covered with 'VM2000', a highly reflective foil from 3 M. This foil has a high reflectivity in a wide range of wavelength and it also shifts photons from the UV into the optical range. It, more or less, doubles the amount of detectable photons, because the photomultipliers used, have an detection maximum between 370 and 400 nm. Thus, a detection efficiency of 98% should be easily achieved. (C) 2009 Elsevier B.V. All rights reserved.

We report the observation of multi-exponential scintillation light emission from a CaMoO4 crystal with slow and fast components after both α-particles or γ-quanta irradiation. The slow components with decay times of ∼5 and ∼15μs produce the main contribution to the light yield. Whereas the fast components with ∼10–50ns decay times observed for the first time with such a crystal at room temperature contribute <1% to the crystal total light yield.

The new generation of experiments searching for neutrinoless double beta decay is aiming at a background level of 10-3counts/(kgkeVy) or better at the respective Q-values. Cosmic ray muons can be a significant contribution due to a number of physics processes. The GERmanium Detector Array, GERDA, located at the Gran Sasso underground laboratory in Italy, uses germanium enriched in 76Ge as source and detector material. Germanium is submerged into liquid nitrogen or argon that acts as cooling medium and radiation shield simultaneously. A detailed Geant4-based Monte Carlo simulation was performed to calculate the photon and neutron fluxes induced by cosmic ray muons. The prompt background contributions from γ-ray and neutron interactions as well as the delayed contributions due to the production of radioactive isotopes within the setup are given. The background can be reduced to the desired level with the muon veto system incorporated in the GERDA design.

The Gerda [1] and Majorana [2] projects, both searching for the neutrinoless double beta-decay of 76Ge, are developing a joint Monte-Carlo simulation framework called MaGe. Such an approach has many benefits: the workload for the development of general tools is shared between more experts, the code is tested in more detail, and more experimental data is made available for validation.