KIP-Veröffentlichungen

ECHo-1K is an experiment designed to measure the electron neutrino mass from the spectrum of the electron capture on ¹⁶³Ho using an array of 100 magnetic micro calorimeters each loaded with 10 Bq of ¹⁶³Ho. In this article, we present the results of our activities in the investigation of possible backgrounds to the electron capture spectrum using GEANT4 based Monte-Carlo simulations of the sources ^166mHo, ⁴⁰K, ²¹⁰Pb and the ²³⁸U decay chain. For standard contaminations of the used materials, the contribution of the investigated sources is well below the background induced by the pile-up of 163Ho decays. Nonetheless, care has to be taken to avoid accidental contamination during the manufacturing and storage of the detectors, since a few mBq in total on the surface of all 100 detectors of either ⁴⁰K (∼ 12mBq) from residual potassium, or ²¹⁰Pb (∼ 4 mBq) from radon emanation yield a background as large as the expected signal.