Published online by Cambridge University Press: 09 March 2009
The control of the extracted beam quality of a nuclear-pumped laser is a major issue. One possible control method involves changing the spatial power deposition profile, which is a function of the gas pressure and the pumping mechanism. Thus, we proposed a combined He-3 and wall coating (e.g., B-10 or U-235) technique. Then, the pump power deposition profile can be adjusted by varying the He-3 partial pressure. To examine this technique, measurements are being performed with an in-core cell by imaging the radiation-induced fluorescence onto a linear diode array located some distance from the cell. Results from these measurements are presented and other related issues such as gas dynamics, index of refraction effects, and efficient beam extraction from a large-volume cavity are discussed.