Integration of Radioactive Material with Microcalorimeter Detectors

• Published in: Journal of low temperature physics Vol. 176; no. 5-6; pp. 1009 - 1014
• Main Authors: Croce, M. P., Bond, E. M., Hoover, A. S., Kunde, G. J., Moody, W. A., Rabin, M. W., Bennett, D. A., Hayes-Wehle, J., Kotsubo, V., Schmidt, D. R., Ullom, J. N.
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01-09-2014
• Subjects: Beta decay; Characterization and Evaluation of Materials; Condensed Matter Physics; Deposition; Detectors; Encapsulation; Magnetic Materials; Magnetism; Microcalorimeters; Physics; Physics and Astronomy; Q values; Radioactive materials; Spectroscopy; Transition-edge sensor microcalorimeter; Nuclear forensics; Neutrino mass
• ISSN: 0022-2291; 1573-7357
• DOI: 10.1007/s10909-013-1045-9

Microcalorimeter detectors with embedded radioactive material offer many possibilities for new types of measurements and applications. We will discuss the designs and methods that we are developing for precise deposition of radioactive material and its encapsulation in the absorber of transition-edge sensor (TES) microcalorimeter detectors for two specific applications. The first application is total nuclear reaction energy (Q) spectroscopy for nuclear forensics measurements of trace actinide samples, where the goal is determination of ratios of isotopes with Q values in the range of 5–7 MeV. Simplified, rapid sample preparation and detector assembly is necessary for practical measurements, while maintaining good energy resolution. The second application is electron capture spectroscopy of isotopes with low Q values, such as
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Ho, for measurement of neutrino mass. Detectors for electron capture spectroscopy are designed for measuring energies up to approximately 6 keV. Their smaller heat capacity and physical size present unique challenges. Both applications require precise deposition of radioactive material and encapsulation in an absorber with optimized thermal properties and coupling to the TES. We have made detectors for both applications with a variety of designs and assembly methods, and will present their development.