Search for Superradiant Emission States in Nuclear Isomer Crystals

摘要

This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). Our objective was to verify the stimulated emission of gamma rays from Te, as claimed by Russian scientists. The reported cross section for stimulated emission was sufficiently large to allow gain in a single-pass gamma-ray laser. The stimulated emission of gamma rays from a nuclear isomer is expected to result in collinear photons and, therefore, should be observable as a sum peak in the gamma-ray spectrum. Skorobogatov and Dzevitskii reported an increase of an order of magnitude in the sum peak (218.56 keV) when a sample of beryllium telluride containing Te was cooled from room temperature to near-liquid-helium temperatures. We have repeated their experiment and have observed no increase in the sum peak above accidental summing. The upper limit for the stimulated-emission cross section based on the three-standard-deviation statistical error is 6.8 x 10 < sup>-21. This result is one order of magnitude lower than the cross section reported by Skorobogatov and Dzevitskii. Our cross section would not allow gain in a single-pass gamma-ray laser. Our results support the position of Baldwin and Solem rather than that of Kamenov.