A novel $^{83\mathrm{m}}$Kr tracer method for characterizing xenon gas   and cryogenic distillation systems
  The radioactive isomer $^{83\mathrm{m}}$Kr has many properties that make it very useful for various applications. Its low energy decay products, like conversion, shake-off and Auger electrons as well as X- and $\gamma$-rays are used for calibration purposes in neutrino mass experiments and direct dark matter detection experiments. Thanks to the short half-life of 1.83 h and the decay to the ground state $^{83}$Kr, one does not risk contamination of any low-background experiment with long- lived radionuclides. In this paper, we present two new applications of $^{83\mathrm{m}}$Kr. It can be used as a radioactive tracer in noble gases to characterize the particle flow inside of gas routing systems. A method of doping $^{83\mathrm{m}}$Kr into xenon gas and its detection, using special custom-made detectors, based on a photomultiplier tube, is described. This technique has been used to determine the circulation speed of gas particles inside of a gas purification system for xenon. Furthermore, 83m Kr can be used to rapidly estimate separation performance of a distillation system. 
S. Rosendahl, K. Bokeloh, E. Brown, I. Cristescu, A. Fieguth, C.   Huhmann, O. Lebeda, C. Levy, M. Murra, S. Schneider, D. V...
astro-ph.IM physics.ins-det