Laser-induced nuclear orientation studies of 1-μs ^85mRb

We have conducted a series of laser-induced nuclear orientation (LINO) experiments with the 1-μs nuclear isomer of ⁸⁵Rb (^85mRb at 514 keV), and present here, along with the results, a quantitative model of the physical processes occurring in the ^85mRb sample which characterizes the observations exceedingly well. The LINO process uses laser optical pumping to produce nuclear orientation, resulting in spatially anisotropic nuclear decay radiation patterns. The use of a cell configuration in these experiments, entirely off-line, has required the careful selection of a suitable parent-daughter system for isomer production, but in return, it allows careful monitoring and control over the processes affecting nuclear orientation. The model presented here incorporates the production and neutralization of the ^85mRb "isomeric atoms", the nuclear orientation achieved through optical pumping, and the aspects associated with detection of the characteristic anisotropic nuclear decay radiation. Predictions of this model accurately match measured absolute signal sizes over extreme variations in experimental conditions. It is hoped that some of the insights gained here will be of general use in the study of laser interactions with short-lived nuclear systems.