Nuclear Facility Experience with the SOFIA Ultra-High-Resolution Microcalorimeter Gamma Spectrometer

Year
2022
Author(s)
Mark Croce - Los Alamos National Laboratory
D.T. Becker - University of Colorado, Boulder, CO, USA
D.A. Bennett - National Institute of Standards and Technology, Boulder, CO, USA
S.T.P. Boyd - University of New Mexico, Albuquerque, NM, USA
R.H. Cantor - STAR Cryoelectronics, Santa Fe, NM, USA
M.H. Carpenter - Los Alamos National Laboratory, Los Alamos, NM, USA
E.A. Feissle - Los Alamos National Laboratory, Los Alamos, NM, USA
J.D. Gard - University of Colorado, Boulder, CO, USA
J. Imrek - National Institute of Standards and Technology, Boulder, CO, USA
G.B. Kim - Lawrence Livermore National Laboratory, Livermore, CA, USA
K.E. Koehler - Los Alamos National Laboratory, Los Alamos, NM, USA
J.A.B. Mates - National Institute of Standards and Technology, Boulder, CO, USA
DG McNeel - Los Alamos National Laboratory, Los Alamos, NM, USA
D.J. Mercer - Los Alamos National Laboratory, Los Alamos, NM, USA
N.J. Ortiz - University of Colorado, Boulder, CO, USA
D.R. Schmidt - National Institute of Standards and Technology, Boulder, CO, USA
K.A. Schreiber - Los Alamos National Laboratory, Los Alamos, NM, USA
D.S. Swetz - National Institute of Standards and Technology, Boulder, CO, USA
L.R. Vale - National Institute of Standards and Technology, Boulder, CO, USA
A.L. Wessels - University of Colorado, Boulder, CO, USA
S.L. Weidenbenner - Los Alamos National Laboratory, Los Alamos, NM, USA
R. Winkler - Los Alamos National Laboratory, Los Alamos, NM, USA
D. Yan - University of Colorado, Boulder, CO, USA
J.N. Ullom - University of Colorado, Boulder, CO, USA
Abstract

The first ultra-high-resolution microcalorimeter gamma spectrometers are now being deployed thanks to extensive recent developments in superconducting transition-edge sensor arrays, readout electronics, cryogenics, and software for pulse processing and isotopic analysis. SOFIA (Spectrometer Optimized for Facility Integrated Applications) is a compact instrument that provides 5 to 10 times better energy resolution than high-purity germanium detectors. Implemented in nuclear facilities and analytical laboratories, this technology has the potential to improve the economics, efficiency, and effectiveness of safeguards and nuclear material accounting by providing a nondestructive isotopic analysis method with precision and accuracy approaching that of destructive analysis. SOFIA has recently been demonstrated in the Los Alamos National Laboratory Plutonium Facility for a range of reference and process materials, in addition to measurements of safeguards-relevant plutonium and uranium isotopic standards. While improved energy resolution has a direct benefit in uncertainty of determined isotopic ratios, it has also become clear that improved nuclear and atomic reference data is needed to realize the potential of this next-generation nondestructive measurement technology. Our team is using available microcalorimeter data from well-characterized isotopic reference materials and gamma-ray energy standards such as Yb-169 to re-determine important values such as gamma-ray branching ratios and X-ray line widths, and incorporate these values into quantitative analysis software. We will discuss our experience with operating the SOFIA instrument in a nuclear facility environment, present quantitative analysis results, efforts to improve nuclear data, and discuss future applications.