A measurement of the beta spectrum of 63Ni using a new type of calorimetric cryogenic detector

A beta spectrometer has been developed using a new type of cryogenic particle detector. The detectors consist of series arrays of superconducting tunnel junctions (SASTJs) fabricated on single crystals of InSb operated at 50 mK. Two detectors are used to completely enclose a beta electron source and are able to make fully calorimetric measurements of beta decay, eliminating both back-scattering and final state effects. ort the results from a precision measurement of the beta spectrum of a 63Ni source. In addition, we will detail the stages in the design and operation of this cryogenic detector which were carried out in order to collect a large number of events (∼108) over long periods (∼28 days).