OBSERVATION OF STIMULATED GAMMA-EMISSION IN MGO-TE-123M

The radioactive-decay rate of impurity Te-123m atoms in MgO was observ ed to decrease with the temperature lowered from 295 to 80 K. It is as sumed that this phenomenon is connected with stimulated gamma emission of the long-lived isomer Te-123m, whose probability should increase w ith decreasing temperature due to the increase of the Mossbauer factor for 88-keV gamma photons. A phenomenological description of the effec t of stimulated gamma radiation (SGR) on the radioactive-decay rate is proposed, and a parameter is introduced which characterizes the SGR i ntensity such that, as this parameter approaches one, a single-pass la ser-shot mode should set in. It is shown that in the geometry used thi s critical mode for MgO:Te-123m can be initiated by increasing the spe cific activity by two orders of magnitude. (C) 1998 American Institute of Physics. [S1063-7834(98)01310-0].