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Cryogenic micro-calorimeters for low energy beta spectroscopy

Conference · · Journal of Low Temperature Physics; (United States)
OSTI ID:5487173
; ;  [1]
  1. Princeton Univ., NJ (United States)

The authors are using calorimeters with completely encapsulated sources to study low energy beta spectra. Their devices work as true calorimeters in the sense that they totally absorb and sum all the various quanta released in a decay into a single temperature pulse with amplitude proportional to the total energy deposited. They use a neutron transmutation doped (NTD) germanium thermistor as the temperature sensor and superconducting NbTi leads, which form a weak thermal link to the cold stage ([approx]80 mK). They have been using superconducting tin as their absorber material, and discuss various techniques for source and absorber preparation. Annealing the absorber leads to shorter pulses with larger amplitude, and significantly improves detector performance. The production of a device to study the beta decay of [sup 107]Pd presented special difficulties due to the low specific activity of this isotope (halflife 6.5 x 10[sup 6] y), and the low enrichment (15%) that was available. This meant it was necessary to incorporate a large amount of palladium into the tin absorber. They avoided a corresponding increase in heat capacity by forming a superconducting PdSn alloy.

OSTI ID:
5487173
Report Number(s):
CONF-930751--
Journal Information:
Journal of Low Temperature Physics; (United States), Journal Name: Journal of Low Temperature Physics; (United States) Vol. 93:3-4; ISSN 0022-2291; ISSN JLTPAC
Country of Publication:
United States
Language:
English