We report on the first results of the MACHe3 (MAtrix of Cells of Helium 3) prototype experiment concerning the measurement of low energy conversion electrons at ultra-low temperature. For the first time, the feasibility of the detection of low energy electrons is demonstrated in superfluid He3-B cooled down to 100 microK. Low energy electrons at 7.3 keV coming from the K shell conversion of the 14.4 keV nuclear transition of a low activity Co57 source are detected, opening the possibility to use a He3-based detector for the detection of Weakly Interacting Massive Particles (WIMPs) which are expected to release an amount of energy higher-bounded by 5.6 keV.
@article{arxiv.astro-ph/0504272,
title = {Low energy conversion electron detection in superfluid He3 at ultra-low temperature},
author = {E. Moulin and C. Winkelmann and J. F. Macias-Perez and Yu. M. Bunkov and H. Godfrin and D. Santos},
journal= {arXiv preprint arXiv:astro-ph/0504272},
year = {2011}
}