First measurement of the beta spectrum of 241Pu with a cryogenic detector

Proceedings of the 17th International Conference on Radionuclide Metrology and its Applications (ICRM 2009)7-11 September 2009 • Bratislava, Slovak RepublicInternational audienceThe LNE-LNHB is developing metallic magnetic calorimeters, a specific type of cryogenic detectors, for beta spectrometry. The aim is the determination of the shape factors of beta spectra. Our latest detector has been designed to measure the spectrum of 241Pu, a pure beta emitter with an endpoint energy of 20.8 keV. In this paper, the detection principle of metallic magnetic calorimeters is explained and a detailed description is given of the realization of the detector enclosing a 241Pu source inside the detector absorber. A spectrum resulting from our first measurement is shown and compared with a theoretical spectrum