Development of Total Decay Energy Spectrometry of α-Emitting Radionuclides Using Metallic Magnetic Calorimeters

Matias Rodrigues (1) , Marouane Laaraj (1) , Martin Loidl (1) , Xavier-François Navick (2) , Riham Mariam (1)

1 LNHB (CEA, LIST) - Laboratoire National Henri Becquerel (CEA, LIST)
2 IRFU - Institut de Recherches sur les lois Fondamentales de l'Univers

Total decay energy spectrometry with cryogenic detectors is a promising technique for radionuclide analysis of α-emitting nuclides. The radioactive sample is embedded in the detector absorber, and the total decay energy for each disintegration is measured as a temperature elevation. We are developing this technique with metallic magnetic calorimeters (MMCs). The main condition of this technique is a detection efficiency close to unity. However, some α-emitting nuclides emit intense γ-rays that can partially escape from the absorber. So a feasibility study for several nuclides has been carried out based on Monte Carlo simulations of the detection efficiency and numerical calculations of the expected energy resolution to identify the radionuclides that can potentially be measured. Furthermore, an MMC prototype has been built and tested. The total decay energy spectrum of Po-210 was measured, and a FWHM energy resolution of 1.25 keV at 5.4 MeV was obtained and a Gaussian width at half maximum of 0.827 (5) keV. The baseline FWHM energy resolution is 207 eV, consistent with the resolution obtained on low-energy L X-rays in the same spectrum at 14 keV.

Mots clés: instrumentation; nuclear instrumentation; detector; spectrometry; Total decay energy; cryogenic detector; radioactivity; ionizing radiation; alpha-rays; alpha spectrometry; detector absorber; disintegration; temperature elevation; calorimeter; metallic magnetic calorimeter; detection efficiency; gamma-rays; Monte Carlo; simulation; particle transport; energy resolution; radionuclide identification; signal processing; spectrum analysis; 210Po; baseline energy resolution; Q spectrometry

Domaines: Instrumentations et Détecteurs [physics.ins-det]; Physique Nucléaire Expérimentale [nucl-ex]

Matias Rodrigues, Marouane Laaraj, Martin Loidl, Xavier-François Navick, Riham Mariam. Development of Total Decay Energy Spectrometry of α-Emitting Radionuclides Using Metallic Magnetic Calorimeters. Journal of Low Temperature Physics, 2018, 193, pp.1263-1268. ⟨10.1007/s10909-018-2008-y⟩. ⟨hal-04563105⟩