The MARE project for neutrino mass measurements from the β-decay of 187Re: Status and perspectives

• Published in: Journal of physics. Conference series 2008-11, Vol.136 (4), p.042055
• Main Authors: Kraft-Bermuth, Saskia, Collaboration, the MARE
• Format: Article
• Language: English
• Subjects: Absorbers (materials); Beta decay; Calorimeters; Detectors; Experiments; Heat measurement; Inductance; Low temperature; Multilayers; Neutrinos; Physics; Rhenium; Rhenium compounds; Rhenium isotopes; Sensitivity; Sensors; Thermistors
• ISSN: 1742-6596; 1742-6588; 1742-6596
• DOI: 10.1088/1742-6596/136/4/042055

The experiment MARE (Microcalorimeters for A Rhenium Experiment) [1] has been introduced at Neutrino 2006 as an experiment complementary to the experiments of Mainz/Troitsk and KATRIN to determine the neutrino mass from single β-decay. Calorimetric low-temperature detectors measure the temperature rise induced by the energy deposition of the β-electron in an absorber of low heat capacity. MARE takes advantage of the β-decaying nuclide with the lowest endpoint energy known to date: 187Re (E0 2.47 keV). Using the β-active 187Re as absorber material eliminates the systematic effects from electrons having to leave a source before reaching the detector. It has already been demonstrated in the past that observing the β-decay spectrum of 187Re with calorimetric detectors provides a suitable method to determine the mass of the electron anti-neutrino from β-endpoint measurements. In a first step, with the experiments MIBETA [2] and MANU [3] a sensitivity of mv ⪅ 15 eV/c2 was achieved, limited by statistics. To compete with the limit of mV ⪅ 0:2 eV/c2 aimed at with KATRIN, MARE will contain several 10000 detectors operated at temperatures around 100 mK. The experiment is divided into two stages: Currently, the first stage MARE-I with 300 detectors and an expected sensitivity of mv ⪅ 2 eV/c2 is being assembled. Two different thermistor concepts, namely compensated- doped silicon semiconductor thermistors and Ir/Ag multilayer transition edge sensors, will be tested in combination with absorbers of metallic rhenium and the dielectric rhenium compound AgReO4 to investigate the systematic uncertainties peculiar to the calorimetric approach. In the second phase MARE-II, large arrays with as many as 10000 detectors each will be deployed. For this second phase, new detector concepts like magnetic calorimeters or kinetic inductance detectors will be tested in parallel to the setting up of MARE-I.