Ultra-high energy resolution microcalorimeter gamma ray spectrometer for high precision
nuclear fuel cycle research

Year
2023
Author(s)
K.A. Schreiber - Los Alamos National Laboratory
A.L. Wessels - University of Colorado, Boulder, CO, USA
DG McNeel - Los Alamos National Laboratory, Los Alamos, NM, USA
M. Keller - University of Colorado, Boulder, CO, USA
M.P. Croce - Los Alamos National Laboratory, Los Alamos, NM, USA
M.H. Carpenter - Los Alamos National Laboratory, Los Alamos, NM, USA
R.U. Schönemann - Los Alamos National Laboratory, Los Alamos, NM, USA
J.W. Ward - Los Alamos National Laboratory, Los Alamos, NM, USA
E.S. Teti - Los Alamos National Laboratory, Los Alamos, NM, USA
D.T. Becker - University of Colorado, Boulder, CO, USA
D. A. Bennett - National Institute of Standards and Technology, Boulder, CO
J.D. Gard - University of Colorado, Boulder, CO, USA
J. Imrek - National Institute of Standards and Technology, Boulder, CO, USA
J.A.B. Mates - National Institute of Standards and Technology, Boulder, CO, 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
D.S. Swetz - National Institute of Standards and Technology, Boulder, CO, USA
J. N. Ullom - National Institute of Standards and Technology, Boulder, CO
A. Williams - Idaho National Laboratory, Idaho Falls, ID, USA
M. Coleman - Idaho National Laboratory, Idaho Falls, ID, USA
B. Storms - Idaho National Laboratory, Idaho Falls, ID, USA
B. Bucher - Idaho National Laboratory, Idaho Falls, ID, USA
E. Seabury - Idaho National Laboratory, Idaho Falls, ID, USA
File Attachment
finalpaper_304_0511042236.pdf1.19 MB
Abstract
Nuclear energy depends on the development of new reactor technologies which are increasingly safe, secure, and economical. In support of this mission, the Materials and Fuels Complex (MFC) Analytical Laboratory at Idaho National Laboratory provides sophisticated analysis of nuclear materials. An important component is nondestructive assay of fresh and spent fuel, reactor components, radioactive waste, and other materials from the nuclear fuel cycle. This assay includes gamma ray spectroscopy, which measures isotopic composition. For an accurate measurement, a gamma ray spectrum with high resolution and high counting statistics is desirable. However, such spectra can be difficult to obtain from the materials to be studied, which often consist of very dilute samples. Here we present a new gamma ray spectrometer, the High Efficiency and Resolution Microcalorimeter Spectrometer, 400 pixels (HERMES-400), developed at Los Alamos National Laboratory in collaboration with the National Institute of Standards and Technology and University of Colorado, installed in the MFC in 2022. The spectrometer uses a microcalorimeter array, a gamma ray detector with unparalleled energy resolution. Microcalorimeters are sensors which operate below 100 milliKelvin and respond sensitively to the absorption of a photon. This can give them energy resolution on the order of 60-80 eV photopeak FWHM (full width half maximum) in the 50-250 keV range. The detector is mounted within a dilution refrigerator, and can measure continuously, permitting multi-day measurements with thousands of counts per second. This gamma ray spectrometer permits precise, high statistics measurements on small amounts of novel nuclear fuel cycle materials. We will discuss the development of this detector and present spectra demonstrating its capabilities.