Year
2018
Abstract
Low-temperature microcalorimeters are creating transformative new capabilities in nuclear material analysis. With at least an order of magnitude better energy resolution than semiconductor detectors, the development of microcalorimeters is intended to close the performance gap between non-destructive and destructive analysis methods. Microcalorimeter technology has advanced rapidly in the past decade, moving from a single pixel proof-of-concept experiment, to an array of hundreds of pixels collecting spectra with tens of millions of counts per hour. Within the next year, we anticipate operating microcalorimeter gamma spectrometers with efficiency and count rate capability comparable to planar high-purity germanium detectors, but ten times better energy resolution. Comprehensive measurements of plutonium-containing materials have proven that this improved energy resolution leads to reduced uncertainty and bias in quantitative analysis of plutonium isotopic ratios. Implemented at a reprocessing facility, rapid, nondestructive microcalorimeter gamma spectroscopy measurements could reduce reliance on sampling, mass spectrometry, and destructive chemical analysis. Decay energy spectroscopy, where trace samples are embedded inside a microcalorimeter detector, can determine actinide isotope ratios even in small particles with no consumption of the sample and minimal preparation. Chemical speciation can be determined nondestructively with microcalorimeter x-ray spectroscopy, which yields information about chemical bonding or oxidation state similar to x-ray absorption fine structure (XAFS) methods that are currently only available at large synchrotron facilities. We will present recent developments in microcalorimeter technology, and discuss applications.