Measurement of the gamma-ray emission probability of 131mXe

Abstract 131m Xe has been standardized by means of an internal gas proportional counting system, employing a length-compensated method. The activity concentration of 131m Xe was measured with a relative standard uncertainty of 0.6%. The gamma-ray emission probability of 131m Xe was then determined as 0.0196(4) by measuring a standard sample of 131m Xe using a high-purity germanium (HPGe) spectrometer.