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Изотопы олова

Олово ( 50 Sn) — элемент с наибольшим количеством стабильных изотопов (десять; три из них потенциально радиоактивны, но распада не наблюдалось). Вероятно, это связано с тем, что 50 — « магическое число » протонов. Кроме того, известны двадцать девять нестабильных изотопов олова, в том числе олово-100 ( 100 Sn) (открыто в 1994 г.) [4] и олово-132 ( 132 Sn), которые оба являются « вдвойне магическими ». Самый долгоживущий радиоизотоп олова — олово-126 ( 126 Sn) с периодом полураспада 230 000 лет. Остальные 28 радиоизотопов имеют период полураспада менее года.

Список изотопов

  1. ^ mSn – Excited nuclear isomer.
  2. ^ ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
  3. ^ # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
  4. ^ a b c # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
  5. ^ Modes of decay:
  6. ^ Bold symbol as daughter – Daughter product is stable.
  7. ^ ( ) spin value – Indicates spin with weak assignment arguments.
  8. ^ Heaviest known nuclide with more protons than neutrons
  9. ^ Believed to decay by β+β+ to 112Cd
  10. ^ a b c d e Fission product
  11. ^ Believed to undergo β−β− decay to 122Te
  12. ^ Believed to undergo β−β− decay to 124Te with a half-life over 1×1017 years
  13. ^ Long-lived fission product

Tin-117m

Tin-117m is a radioisotope of tin. One of its uses is in a particulate suspension to treat canine synovitis (radiosynoviorthesis).[7]

Tin-121m

Tin-121m (121mSn) is a radioisotope and nuclear isomer of tin with a half-life of 43.9 years.

In a normal thermal reactor, it has a very low fission product yield; thus, this isotope is not a significant contributor to nuclear waste. Fast fission or fission of some heavier actinides will produce tin-121 at higher yields. For example, its yield from uranium-235 is 0.0007% per thermal fission and 0.002% per fast fission.[8]

Tin-126

Tin-126 is a radioisotope of tin and one of the only seven long-lived fission products of uranium and plutonium. While tin-126's half-life of 230,000 years translates to a low specific activity of gamma radiation, its short-lived decay products, two isomers of antimony-126, emit 17 and 40 keV gamma radiation and a 3.67 MeV beta particle on their way to stable tellurium-126, making external exposure to tin-126 a potential concern.

Tin-126 is in the middle of the mass range for fission products. Thermal reactors, which make up almost all current nuclear power plants, produce it at a very low yield (0.056% for 235U), since slow neutrons almost always fission 235U or 239Pu into unequal halves. Fast fission in a fast reactor or nuclear weapon, or fission of some heavy minor actinides such as californium, will produce it at higher yields.

References

  1. ^ a b c d e Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.
  2. ^ "Standard Atomic Weights: Tin". CIAAW. 1983.
  3. ^ Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (2022-05-04). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN 1365-3075.
  4. ^ K. Sümmerer; R. Schneider; T Faestermann; J. Friese; H. Geissel; R. Gernhäuser; H. Gilg; F. Heine; J. Homolka; P. Kienle; H. J. Körner; G. Münzenberg; J. Reinhold; K. Zeitelhack (April 1997). "Identification and decay spectroscopy of 100Sn at the GSI projectile fragment separator FRS". Nuclear Physics A. 616 (1–2): 341–345. Bibcode:1997NuPhA.616..341S. doi:10.1016/S0375-9474(97)00106-1.
  5. ^ Wang, Meng; Huang, W.J.; Kondev, F.G.; Audi, G.; Naimi, S. (2021). "The AME 2020 atomic mass evaluation (II). Tables, graphs and references*". Chinese Physics C. 45 (3): 030003. doi:10.1088/1674-1137/abddaf.
  6. ^ Shen, Hongtao; Jiang, Shan; He, Ming; Dong, Kejun; Li, Chaoli; He, Guozhu; Wu, Shaolei; Gong, Jie; Lu, Liyan; Li, Shizhuo; Zhang, Dawei; Shi, Guozhu; Huang, Chuntang; Wu, Shaoyong (February 2011). "Study on measurement of fission product nuclide 126Sn by AMS" (PDF). Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms. 269 (3): 392–395. doi:10.1016/j.nimb.2010.11.059.
  7. ^ "https://www.nrc.gov/site-help/search.html?site=AllSites&searchtext=synovetin" (PDF). {{cite web}}: External link in |title= (help)
  8. ^ a b M. B. Chadwick et al, "Evaluated Nuclear Data File (ENDF) : ENDF/B-VII.1: Nuclear Data for Science and Technology: Cross Sections, Covariances, Fission Product Yields, and Decay Data", Nucl. Data Sheets 112(2011)2887. (accessed at https://www-nds.iaea.org/exfor/endf.htm)