Magnetic Microcalorimeter (MMC) Gamma Detectors with Ultra-High Energy Resolution
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Univ. of New Mexico, Albuquerque, NM (United States)
- Star Cryoelectronics, Santa Fe, NM (United States)
The goal of this LCP is to develop ultra-high resolution gamma-ray detectors based on magnetic microcalorimeters (MMCs) for accurate measurements of nuclear decay data and NDA of nuclear materials. For highest energy resolution, we are introducing erbium-doped silver (Ag:Er) as a novel sensor material and implement several geometry and design changes to improve the signal-to-noise ratio. The detector sensitivity will be increased by developing arrays of 32 Ag:Er pixels read out by 16 SQUID preamplifiers, and by developing a cryogenic Compton veto to reduce the spectral background. For highest energy resolution we will operate the MMC detector arrays in a dilution refrigerator with a base temperature <10 mK. The detector performance and utility will be demonstrated with radioactive sources of interest to the safeguards community. In FY16 and FY17, we had purchased a liquid-cryogen-free dilution refrigerator and installed 16 SQUID preamplifiers and writing for MMC detector operation at ~10 mK. We have also developed the process to fabricate the first Ag:Er-based MMCs, built prototype detector arrays and tested them with different radioactive sources. We have also shown that our MMC detectors can achieve the LCP goal of an energy resolution below 50 eV as needed to resolve most closelyspaced lines of interest for NDA. The goals for FY18 were then 1) to optimize the MMC design based on the measured detector characteristics and to increase the array size to 32-pixels for increased sensitivity, and 2) to demonstrate the utility of MMC gamma-ray detectors in applications relevant in nuclear safeguards.
- Research Organization:
- Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE National Nuclear Security Administration (NNSA)
- DOE Contract Number:
- AC52-07NA27344
- OSTI ID:
- 1491989
- Report Number(s):
- LLNL-TR-765370; 955511
- Country of Publication:
- United States
- Language:
- English
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