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)

Determination of Cross-Sections of Fast-Muon-Induced Reactions to Cosmogenic Radionuclides

%NA54 %title\\ \\We propose to measure cross-sections for fast muon-induced production of radionuclides. Firstly to study the contribution of fast-muon-induced reactions to the in-situ production of cosmogenic radionuclides in the lithosphere. Concrete is used to simulate the rock and to generate a secondary particle shower. The reaction channels to be measured are: C to $^{10}$Be, O to $^{10}$Be and $^{14}$C, Si to $^{26}$Al, S to $^{26}$Al, Ca to $^{36}$Cl, Fe to $^{53}$Mn and $^{205}$Tl to $^{205}$Pb. The energy dependent cross-section can be described by one single parameter $\sigma_0$ and the energy dependence $\rm\overline{E}^{0.7}$ on the mean energy $\rm\overline{E}$. The irradiations of the targets is done at CERN. The produced radionuclides are measured by accelerator mass spectrometry in Munich and Zurich.\\ \\Secondly, muon induced signals can be a major source of background in experiments with low event rates located deep underground. We intent to study the produced radioactivity by fast-muon-induced reactions in a liquid scintillation detector. Our main interest is the measurement of the cross sections for $^{12}$C to $^{11}$C and $^{7}$Be. In addition we will study the produced radioactivity in targets of Saphire(Al$_2$O$_3$) and Cu for a cryogenic dark matter detector. \\ \

Determination of Minor and Trace Elements in Kidney Stones by X-Ray Fluorescence Analysis

The determination of accurate material composition of a kidney stone is crucial for understanding the formation of the kidney stone as well as for preventive therapeutic strategies. Radiations probing instrumental activation analysis techniques are excellent tools for identification of involved materials present in the kidney stone. In particular, x-ray fluorescence (XRF) can be very useful for the determination of minor and trace materials in the kidney stone. The X-ray fluorescence measurements were performed at the Radiation Measurements and Spectroscopy Laboratory (RMSL) of department of nuclear engineering of Missouri University of Science and Technology and different kidney stones were acquired from the Mayo Clinic, Rochester, Minnesota. Presently, experimental studies in conjunction with analytical techniques were used to determine the exact composition of the kidney stone. A new type of experimental set-up was developed and utilized for XRF analysis of the kidney stone. The correlation of applied radiation source intensity, emission of X-ray spectrum from involving elements and absorption coefficient characteristics were analyzed. To verify the experimental results with analytical calculation, several sets of kidney stones were analyzed using XRF technique. The elements which were identified from this techniques are Silver (Ag), Arsenic (As), Bromine (Br), Chromium (Cr), Copper (Cu), Gallium (Ga), Germanium (Ge), Molybdenum (Mo), Niobium (Nb), Rubidium (Rb), Selenium (Se), Strontium (Sr), Yttrium (Y), Zirconium (Zr). This paper presents a new approach for exact detection of accurate material composition of kidney stone materials using XRF instrumental activation analysis technique