PRACTICAL, VISIBLE WAVELENGTH NUCLEAR-PUMPED LASER

A practical, visible nuclear-pumped laser (NPL) has been sought at the University of Illinois and other laboratories for a number of years. Yet, the results from successful visible NPLs to date have not been fu lly satisfactory, e.g., the threshold pumping power is too high for co nventional applications. Progress in recent studies of He-3-Ne-H-2 as a candidate NPL operating in the visible region at 585.3 nm on the P-2 (1)-S-1(2) Ne transition is described. We obtained lasing on the above transition for He-3-Ne-H-2 concentrations of 1,140, 588, and 412 torr , respectively, with the laser cavity placed in the beamport of the Un iversity of Illinois TRIGA reactor. The threshold thermal neutron flux is 10(14) n/cm2-s, corresponding to a threshold pumping power of 5 W/ cm3.