Superconducting Detectors for Neutrino Mass Measurement

Assessing the absolute neutrino mass scale is one of the major challenges in particle physics and astrophysics nowadays. A powerful tool to directly estimate the effective electron neutrino mass consists in the calorimetric measurement of the energy released within a nuclear beta decay. The progresses made over the last few decades on low-temperature detector technologies have permitted to design experiments with expected sensitivities on the neutrino mass below 1 eV/c
²
with the calorimetric approach. Despite the remarkable performances in both energy (~ eV at keV) and time resolutions $(\sim\! 1\ \mu\text{s})$ on the single channel, a large number of detectors working in parallel is required to reach a sub-eV sensitivity. Microwave frequency-domain readout provides a powerful technique to read out large arrays of low-temperature detectors, such as transition edge sensors (TESs) or microwave kinetic inductance detectors (MKIDs). In this way, the multiplex factor is only limited by the bandwidth of the available commercial fast digitizers. The microwave multiplexing system will be used to read out the TES array of the HOLMES experiment, which is made of 1000
¹⁶³
Ho-implanted microcalorimeters. HOLMES is a new experiment that aims to measure the electron neutrino mass by means of the electron capture decay of
¹⁶³
Ho with an expected sensitivity of the order of the eV/c
²
.