Physics:Iridium-192
| General | |
|---|---|
| Symbol | 192Ir |
| Names | iridium-192, Ir-192 |
| Protons | 77 |
| Neutrons | 115 |
| Nuclide data | |
| Natural abundance | synthetic |
| Half-life | 73.827 days |
| Parent isotopes | 192mOs (β−) |
| Decay products | 192Pt 192Os |
| Isotope mass | 191.9626050(18) u |
| Spin | 4+ |
| Decay modes | |
| Decay mode | Decay energy (MeV) |
| Isotopes of Chemistry:iridium Complete table of nuclides | |
Iridium-192 (symbol 192Ir) is a radioactive isotope of iridium, with a half-life of 73.827 days.[1] It decays by emitting beta (β) particles and gamma (γ) radiation. About 96% of 192Ir decays occur via emission of β and γ radiation, leading to 192Pt. Some of the β particles are captured by other 192Ir nuclei, which are then converted to 192Os. Electron capture is responsible for the remaining 4% of 192Ir decays.[2] Iridium-192 is normally produced by neutron activation of natural-abundance iridium metal.[3] Iridium-192 is a very strong gamma ray emitter, with a gamma dose-constant of approximately 1.54 μSv·h−1·MBq−1 at 30 cm, and a specific activity of 341 TBq·g−1 (9.22 kCi·g−1).[4][5] There are seven principal energy packets produced during its disintegration process ranging from just over 0.2 to about 0.6 MeV. It is commonly used as a gamma ray source in industrial radiography to locate flaws in metal components.[6] It is also used in radiotherapy as a radiation source, in particular in brachytherapy. Iridium-192 has accounted for the majority of cases tracked by the U.S Nuclear Regulatory Commission in which radioactive materials have gone missing in quantities large enough to make a dirty bomb.[7]
The metastable isomer 192m2Ir is iridium's most stable isomer. It decays by isomeric transition with a half-life of 241 years,[8] which makes it unusual, both for its long half-life for an isomer, and that said half-life greatly exceeds that of the ground state of the same isotope.
See also
References
- ↑ "Radioisotope Brief: Iridium-192 (Ir-192)". http://emergency.cdc.gov/radiation/isotopes/iridium.asp.
- ↑ Braggerly, L. L. (1956). The radioactive decay of Iridium-192 (PDF) (Ph.D. thesis). Pasadena, Calif.: California Institute of Technology. pp. 1, 2, 7. doi:10.7907/26VA-RB25.
- ↑ "Isotope Supplier: Stable Isotopes and Radioisotopes from ISOFLEX - Iridium-192" (in en). https://www.isoflex.com/products/radioisotopes/iridium-isotopes.
- ↑ Delacroix, D; Guerre, J P; Leblanc, P; Hickman, C (2002). "Radionuclide and Radiation Protection Data Handbook". Radiation Protection Dosimetry (Ashford, Kent: Nuclear Technology Publishing) 98 (1): 9–168. doi:10.1093/OXFORDJOURNALS.RPD.A006705. ISBN 1870965876. PMID 11916063. https://pdfs.semanticscholar.org/fbb1/7281dae98db83fe20df96b9d879c0c73b199.pdf.
- ↑ Unger, L M; Trubey, D K (May 1982). Specific Gamma-Ray Dose Constants for Nuclides Important to Dosimetry and Radiological Assessment (Report). Oak Ridge National Laboratory. https://www.orau.org/documents/ivhp/health-physics/ornl-rsic-45.pdf.
- ↑ Charles Hellier (2003). Handbook of Nondestructive Evaluation. McGraw-Hill. p. 6.20. ISBN 978-0-07-028121-9.
- ↑ Steve Coll (March 12, 2007). "The Unthinkable". The New Yorker. http://www.newyorker.com/reporting/2007/03/12/070312fa_fact_coll?printable=true. Retrieved 2007-03-09.
- ↑ Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (2003), "The NUBASE evaluation of nuclear and decay properties", Nuclear Physics A 729: 3–128, doi:10.1016/j.nuclphysa.2003.11.001, Bibcode: 2003NuPhA.729....3A, https://hal.archives-ouvertes.fr/in2p3-00020241/document
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