Bismuth-207
Although bismuth-209 is now known to be radioactive, it has classically been considered to be a stable isotope because it has a half-life of approximately 2.01×1019 years, which is more than a billion times the age of the universe. Besides 209Bi, the most stable bismuth radioisotopes are 210mBi with a half-life of 3.04 million years, 208Bi with a half-life of 368,000 years and 207Bi, with a half-life of 32.9 years, none of which occurs in nature.
Samples of lichen, moss, soil and air collected since 1961 in Greenland, Svalbard, Iceland, the Faroe Islands, Sweden and Denmark have been remeasured for γ-emitting radionuclides by Ge(Li) spectroscopy. The samples have shown the presence of 207Bi (physical half-life 38 years), a nuclide which has not been reported earlier in world-wide fallout. The concentrations of 207Bi have been compared with those of 60Co, 125Sb, and 137Cs. From this comparison the production of 207Bi is estimated at 1 PBq. It is assumed that the 207Bi is created in thermonuclear tested explosions in general and that in particular the 55Mt detonation of 30 October 1961 at Novaya Zemlya may have produced this activation product.
Spectrum (Fullscreen)
10 minute measurement with a High Purity Germanium (HPGe) radiation detector.
Metadata
| Isotope: | Bismuth |
|---|---|
| Mass number: | 207 |
| Atomic number: | 83 |
| Neutron number: | 124 |
| … | … |
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