SDIO/IST Ultrashort Wavelength Laser: Novel Experimental Schemes for Observing the Mossbauer Effect in Long-Lived Nuclear Levels.

The development of gamma-ray lasers GRASERS will, in all probability, depend on the utilization of recoillessly emitted gamma rays from nuclear transitions, i.e. the Mossbauer effect ME. Past research in Mossbauer spectroscopy which relates to GRASERS is briefly reviewed. The nuclear lifetimes, required from practical considerations, may have to be on the order of seconds, if storage and transfer processes prove infeasible. It is not clear that the ME has been observed in such long-lived states. Even if such long-lived states are not needed directly for GRASERS, successful observation of the ME in such a system will answer important questions of line broadening due to field inhomogeneities in single crystals. We propose some novel experimental schemes to observe the ME in 109 Ag whose relevant lifetime is about 40 seconds. The techniques proposed are coincidence Mossbauer spectroscopy, conversion-electron Mossbauer spectroscopy, gravitational line sweeping, and gamma-ray self absorption. Preliminary results using the last technique are presented. Possible future, relevant ME research is discussed.