Half-life estimation of the first excited state of {sup 229}Th by using {alpha}-particle spectrometry

Journal Article · Tue Sep 15 00:00:00 EDT 2009 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PHYSREVC.80.034315· OSTI ID:21293826

Kikunaga, H ^[1]; Kasamatsu, Y ^[2]; Haba, H ^[3]; Mitsugashira, T ^[4]; Hara, M ^[5]; Takamiya, K ^[6]; Ohtsuki, T ^[7]; Yokoyama, A; Nakanishi, T ^[8]; Shinohara, A ^[1]

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1. Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043 (Japan)
2. Advanced Science Research Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan)
3. Nishina Center for Accelerator-Base Science, RIKEN, Wako, Saitama 351-0198 (Japan)
4. Institute for Material Research, Tohoku University, Sendai, Miyagi 980-8577 (Japan)
5. International Research Center for Nuclear Materials Science, Tohoku University, Oarai-machi, Ibaraki 311-1313 (Japan)
6. Research Reactor Institute, Kyoto University, Kumatori, Osaka 590-0494 (Japan)
7. Laboratory of Nuclear Science, Tohoku University, Sendai, Miyagi 982-0826 (Japan)
8. Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa, Ishikawa 920-1192 (Japan)

To search for a direct-decay signal from the isomer {sup 229}Th{sup m}, {alpha}-particle spectra of {sup 229}Th{sup m,g} produced from 93 mg of {sup 233}U have been measured by using a rapid and high-resolution {alpha}-particle spectrometry, which can distinguish {alpha} lines of {sup 229}Th{sup m} from those of its ground state. Although {alpha} events were not obtained in the expected energy region for {sup 229}Th{sup m} with the exception of those derived from {sup 229}Th{sup g}, we can estimate that the half-life of {sup 229}Th{sup m} is shorter than 2 h at 3{sigma} confidence level under the chemical condition of chloride or hydroxide.

• OSTI ID: 21293826
• Journal Information: Physical Review. C, Nuclear Physics, Vol. 80, Issue 3; Other Information: DOI: 10.1103/PhysRevC.80.034315; (c) 2009 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2813
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ALPHA PARTICLES
ALPHA SPECTROSCOPY
CHLORIDES
EXCEPTIONS
EXCITED STATES
GROUND STATES
HALF-LIFE
ISOMERS
RESOLUTION
SPECTRA
SPECTROSCOPY
THORIUM 229
URANIUM 233