Suppression of the internal Conversion Decay of Th-229m (FY19Q1 report)
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
To measure the decay energy of metastable Th-229m, we had proposed to modify an existing experiment by placing a MgF2 crystal between our U-233 source and a high-resolution STJ photon detector. Metastable Th-229m nuclei produced in the decay of U-233 would be absorbed in the MgF2, but since the MgF2 bandgap of ~10eV exceeds the energy of the metastable state, decay by internal conversion is expected to be suppressed. Th-229m can then only decay by gamma emission, and the ~7.8 eV gamma energy can be transmitted through the MgF2 and detected by the STJ detector. The spectra are calibrated with a pulsed 355 nm laser.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE National Nuclear Security Administration (NNSA)
- DOE Contract Number:
- AC52-07NA27344
- OSTI ID:
- 1491980
- Report Number(s):
- LLNL-TR-765340; 955347
- Country of Publication:
- United States
- Language:
- English
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