Calibration of liquid argon and neon detectors with ^{83}Kr^{m}

We report results from tests of Kr-83(m) as a calibration source in liquid argon and liquid neon. Kr-83(m) atoms are produced in the decay of Rb-83, and a clear Kr-83(m) scintillation peak at 41.5 keV appears in both liquids when filling our detector through zeolite coated with Rb-83. Based on this scintillation peak, we observe 6.0 photoelectrons/keV in liquid argon with a resolution of 8.2% (sigma/E) and 3.0 photoelectrons/keV in liquid neon with a resolution of 19% (sigma/E). The observed peak intensity subsequently decays with the Kr-83(m) half-life after stopping the fill, and we find evidence that the spatial location of Kr-83(m) atoms in the chamber can be resolved. Kr-83(m) will be a useful calibration source for liquid argon, neon dark matter, and solar neutrino detectors.