The alpha-decay of a low energy isomer of 229Th at about 3.5 eV was sought by producing it through the (γ,n) reaction on a 230Th target. Thorium isotopes in the reaction products were isolated and purified by anion exchange chromatography in a concentrated nitric acid medium to remove lanthanides fission products. The thorium fraction was further purified by samarium fluoride coprecipitation and the precipitate was mounted as a source for α-spectroscopy. Decaying α-signals were observed in the energy region that was expected for 229mTh, i.e., between 4.83 and 5.08 MeV. The half-life of the decaying component was determined from repeated experiments to be 13.9±3 hours.
ASJC Scopus subject areas
- Analytical Chemistry
- Nuclear Energy and Engineering
- Radiology Nuclear Medicine and imaging
- Public Health, Environmental and Occupational Health
- Health, Toxicology and Mutagenesis