Speaker
Description
The search for neutrinoless double beta decay (0νββ) is fundamental to understand the nature of neutrinos, test lepton number violation, and probe their mass generation mechanism. Since this process is expected to be extremely rare, next-generation experiments require tonne-scale detectors with ultra-low backgrounds.
Low-temperature calorimeters are among the most promising technologies
for 0νββ searches, but scaling them to the tonne scale poses significant challenges since they must operate at ∼10 mK where the thermal budget is extremely limited. This makes impractical—if not impossible—for each detector to have a dedicated readout channel.
Microwave multiplexing (µMUX) offers a promising solution, enabling hundreds of detectors to be read out over a single transmission line while preserving high signal-to-noise ratio and bandwidth. Although µMUX is established for microcalorimeters, its application to macrocalorimeters is in an early stange and still needs to be demonstrated. This effort is especially relevant for the CUPID-1T experiment, which is expected to deploy approximately 1870 kg of detector mass: more than 3000 macrocalorimeters. Therefore, a scalable multiplexed readout is essential for CUPID-1T to achieve the target 0νββ half-life discovery sensitivity of 8 × 10^27 years, corresponding to an effective Majorana mass sensitivity in the range of 4.4-7.3 meV.
This poster presents preliminary results from a µMUX readout applied
to TES sensors coupled to microcalorimeters, focusing on noise performance and initial tests with an Fe-55 source. Strategies to extend this approach to macrocalorimeters are outlined, presenting a design based on an array of 1 cm^3 crystals that is going to be operated in the same cryogenic system. The ultimate goal is to develop and operate a µMUX readout for a tower of macrocalorimeters meeting the requirements of CUPID-1T.