Krypton-85

Krypton-85, 85Kr
General
Symbol85Kr
Nameskrypton-85, 85Kr, Kr-85
Protons (Z)36
Neutrons (N)49
Nuclide data
Half-life (t1/2)10.756 years
Isotope mass84.9125273(21) Da
Spin9/2+
Excess energy−81480.267 keV
Binding energy8698.562 keV
Decay products85Rb
Decay modes
Decay modeDecay energy (MeV)
Beta decay0.687
Beta decay0.173
Isotopes of krypton
Complete table of nuclides

Krypton-85 (85Kr) is a radioisotope of krypton.

Krypton-85 has a half-life of 10.756 years and a maximum decay energy of 687 keV.[1] It decays into stable rubidium-85. Its most common decay (99.57%) is by beta particle emission with a maximum energy of 687 keV and an average energy of 251 keV. The second most common decay (0.43%) is by beta particle emission (maximum energy of 173 keV) followed by gamma ray emission (energy of 514 keV).[2] Other decay modes have very small probabilities and emit less energetic gamma rays.[1][3] Krypton-85 is mostly synthetic, though it is produced naturally in trace quantities by cosmic ray spallation.

In terms of radiotoxicity, 440 Bq of 85Kr is equivalent to 1 Bq of radon-222, without considering the rest of the radon decay chain.

  1. ^ a b "WWW Table of Radioactive Isotopes - Kr85". Lawrence Berkeley Laboratories, USA. Archived from the original on 2015-06-11. Retrieved 2015-05-30.
  2. ^ M. Gorden; et al. (15 July 2011). "Pinellas Plant – Occupational Environmental Dose rev1" (PDF). ORAU. Retrieved 2015-05-30.
  3. ^ H. Sievers (1991). "Nuclear data sheets update for A=85". Nuclear Data Sheets. 62: 271–325. Bibcode:1991NDS....62..271S. doi:10.1016/0090-3752(91)80016-Y.