Aluminum as a source of background in low background experiments

Neutrinoless double beta decay would be a key to understanding the nature of neutrino masses. The next generation of High Purity Germanium experiments will have to be operated with a background rate of better than 10^-5 counts/(kg y keV) in the region of interest around the Q value of the decay. Therefore, so far irrelevant sources of background have to be considered. The metalization of the surface of germanium detectors is in general done with aluminum. The background from the decays of 22Na, 26Al, 226Ra and 228Th introduced by this metalization is discussed. It is shown that only a special selection of aluminum can keep these background contributions acceptable.Comment: 11 pages, 3 Tables, 11 Figures, accepted for publication in NIM

Muon-induced production of radioactive isotopes in scintillation detectors

The production of radioactive isotopes in scintillation detectors by muons and their secondary shower particles has been studied experimentally at the SPS muon beam at CERN. This paper shows the results obtained in cross-section measurements on liquid scintillator targets, especially on 12C which is the most relevant target in these organic materials. Their energy dependence has been deduced from the cross-sections determined at two muon energies 100 and 190 GeV. Based on the measured cross-sections the muon-induced background rates for the forthcoming solar neutrino experiments BOREXINO and KAMLAND have been calculated for different energy regions that are relevant for solar neutrino physics

Muon induced background in solar neutrino experiments

In this article the muon induced spallation background in forthcoming and future solar neutrino experiments like BOREXINO, KAMLAND, LENS and LIQUID XENON is being discussed. The results of cross section measurements at the SPS muon beam at CERN to determine the muon induced insitu production of radioactive isotopes in scintillator based targets are presented as well as the calculated and estimated background rates for the solar neutrino experiments mentioned above. (17 refs)