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Radiopharmaceuticals for Diagnostics
Published in Michael Ljungberg, Handbook of Nuclear Medicine and Molecular Imaging for Physicists, 2022
Jim Ballinger, Jacek Koziorowski
Krypton-81m [81mKr] (t½ 13 s, IT 100%, principal γ emission 190 keV (68%)) is a generator-produced radioactive noble gas that is obtained from Rubidium-81 using a [81Rb]/[81mKr] generator. 81Rb is a cyclotron produced radiometal with a half-life of 4.6 h, and which is produced either by the [82Kr](p,2n)[81Rb] reaction using an incident proton energy of 20–30 MeV or the [natKr](p,x)[81Rb] reaction using an incident proton energy of 40–70 MeV [4]. The half-life of 81Rb means that the generator must be produced on a daily basis and is expensive to use. 81mKr is breathed in as a gas. The sole clinical use of 81mKr is for lung ventilation imaging, used in conjunction with lung perfusion imaging for diagnosis of pulmonary embolism (see section 2.3.4.2).
Applied Chemistry and Physics
Published in Robert A. Burke, Applied Chemistry and Physics, 2020
Krypton, Kr, is an elemental, colorless, odorless, inert gas. It is noncombustible, nontoxic and nonreactive; however, it is an asphyxiant gas and displaces oxygen in the air. Krypton 85 is radioactive and has a half-life of 10.3 years. The 4-digit identification number for krypton is 1056 as a compressed gas and 1970 as a cryogenic liquid. These forms of krypton are not radioactive. Radioactive isotopes of krypton are shipped under radioactive labels and placards as required. Its primary uses are in the activation of phosphors for self-luminous markers, detection of leaks and medicine to trace blood flow.
Statistical Mechanics
Published in Marc J. Assael, Geoffrey C. Maitland, Thomas Maskow, Urs von Stockar, William A. Wakeham, Stefan Will, Commonly Asked Questions in Thermodynamics, 2022
Marc J. Assael, Geoffrey C. Maitland, Thomas Maskow, Urs von Stockar, William A. Wakeham, Stefan Will
The power of the two-parameter principle of corresponding states can be demonstrated by estimating the density of argon from the density of krypton at some other temperature and pressure. In this example, the critical temperature and critical pressure are the scaling parameters. The density of krypton at T = 348.15 K and p = 2 MPa is 59.28 kg m−3 (Evers et al. 2002). The critical temperature, Tc, the critical pressure, pc, and the critical mass density, ρc, of krypton are 209.48 K, 5.525 MPa and 909.21 kg m−3, respectively (Lemmon et al. 2018). For Kr, the reduced temperature Tr, pressure pr and mass density ρr are as follows Tr,Kr=TTc,Kr=348.15K209.48K=1.662,pr,Kr=ppc,Kr=2MPa5.525MPa=0.362
High-Energy Tritium Ion and α-Particle Release from the Near-Surface Layer of Lithium During Neutron Irradiation in the Nuclear Reactor Core
Published in Fusion Science and Technology, 2023
Erlan Batyrbekov, Mendykhan Khasenov, Mazhyn Skakov, Yuriy Gordienko, Kuanysh Samarkhanov, Andrey Kotlyar, Alexandr Miller, Vadim Bochkov
For krypton, there are data for only three levels, and the values of the helium quenching rate constants are large: 2p2 = 83 × 10−11 cm3s−1, 2p3 = 110 × 10−11 cm3s−1, and 2p4 = 24 × 10−11 cm3s−1.[38] Thus, krypton is not suitable as a working gas.