Nuklida · radioaktif
Kripton-85 (⁸⁵Kr)
Kripton-85 (⁸⁵Kr) adalah isotop radioaktif kripton dengan 36 proton dan 49 neutron (nomor massa 85). Waktu paruhnya 10,728 tahun (± 0,007 tahun), meluruh terutama lewat peluruhan beta minus (β⁻).
Data nuklida
- Unsur
- Kripton (Kr, Z = 36)
- Nomor massa (A)
- 85
- Proton (Z)
- 36
- Neutron (N)
- 49
- Massa atom
- 84.912527260 ± 0.000002147 u
- Waktu paruh
- 10,728 tahun (± 0,007 tahun)
- Mode peluruhan
- Peluruhan beta minus (β⁻) ( 100 %)
- Inti anak
- Rubidium-85 (⁸⁵Rb)
- Tahun penemuan
- 1940
- Sumber data
- IAEA Atomic Mass Data Center (NUBASE) and IUPAC CIAAW, via PubChem
Kegunaan isotop kripton
- 85Kr (with a half-life of 10.7 years) has been used in atmospheric monitoring programs to track the effect of atomic facilities on the surrounding environment. 85Kr is co-generated with plutonium in the fuel elements of nuclear fission reactors and can be monitored at short distances (i.e. 1 to 5 km) from an area of clandestine plutonium separation from spent fuel from the nuclear reactor. The differences in 85Kr levels in the atmosphere have been used to estimate the amount of plutonium separated at weekly intervals. The production of plutonium for nuclear weapons and the output from commercial reprocessing plants have released large amounts of 85Kr into the atmosphere.
- 85Kr has minimal natural production in the Earth, but its concentration in the atmosphere has increased steadily because of human activities related to the nuclear industry. 85Kr enters oceans, lakes, and groundwater through equilibration of the water with air. 85Kr is produced terrestrially as a fission product of nuclear reactors and released into the atmosphere with the noble gases. It is also produced in the atmosphere via the cosmic ray neutron-activation reaction, 84Kr (n, γ) 85Kr. Thus, the 85Kr specific activity can be used to determine the time since water was isolated from the atmosphere (Fig. IUPAC.36.1). This approach provides a valuable addition to the use of tritium (3H) as an indicator of ocean circulation and groundwater age on decadal (a period of 10 consecutive years) time scales,. Krypton stable isotopes react in the upper atmosphere by cosmic-ray-induced spallation and neutron activation to produce radioactive 81Kr, with a half-life of approximately 2.1×105 years. In the atmosphere, 81Kr is chemically inert and has a long residence time; because of these characteristics, it is expected that 81Kr has a relatively constant and well-constrained atmospheric source. Natural cosmogenic 81Kr is incorporated from air into infiltrating groundwater and has been used to determine the age of groundwater over time scales ranging to over 106 years,,,.
- 85Kr has been used as the illumination element of indicator lights of appliances and can be combined with phosphors to create materials that glow in the dark. Light is created when radiation from 85Kr strikes the phosphor. 85Kr can be used to detect container leaks by placing the radioactive gas inside a container and measuring (with a radiation detecting device) the amount of radioactive 85Kr that escapes. Because the gas is inert, Kr will not react with anything else in the container.
- A patient can inhale gaseous radioactive 85Kr, which is then absorbed in the bloodstream, enabling the blood flow of the patient to be studied. Movement of the 85Kr can be tracked with a radiation detector to reveal pathways followed by the blood and to quantify blood velocity,,.
Isotop kripton lainnya
⁶⁷Kr, ⁶⁸Kr, ⁶⁹Kr, ⁷⁰Kr, ⁷¹Kr, ⁷²Kr, ⁷³Kr, ⁷⁴Kr, ⁷⁵Kr, ⁷⁶Kr, ⁷⁷Kr, ⁷⁸Kr, ⁷⁹Kr, ⁸⁰Kr, ⁸¹Kr, ⁸²Kr, ⁸³Kr, ⁸⁴Kr, ⁸⁶Kr, ⁸⁷Kr, ⁸⁸Kr, ⁸⁹Kr, ⁹⁰Kr, ⁹¹Kr, ⁹²Kr, ⁹³Kr, ⁹⁴Kr, ⁹⁵Kr, ⁹⁶Kr, ⁹⁷Kr, ⁹⁸Kr, ⁹⁹Kr, ¹⁰⁰Kr, ¹⁰¹Kr