  We report the first isotopic composition measurements of trinitite, nuclear
detonation debris from the Trinity test, using the novel forensics technique of
decay energy spectroscopy (DES). DES measures the unique total decay energy (Q
value) of each alpha-decaying isotope in a small radioactive sample embedded in
a microcalorimeter detector. We find that DES can measure the major
alpha-decaying isotopes in small particles of trinitite with no dissolution or
chemical processing. These first measurements demonstrate the potential of DES
to provide a radiometric isotopic characterization method with sensitivity and
precision to complement traditional forensics techniques.
