Investigations of NPL problems were begun at VNIITF in 1979, and in 1981 the first experiments were carried out on pumping a He-Xe mixture with uranium fission fragments [31]. In contrast to the majority of experimental studies, in which the laser cells were placed close to the cores of the pulsed reactors, the VNIITF experiments used the specialized EBR-L setup, which included a fast neutron pulsed reactor and laser cell (see Chap. 2, Sect. 2.5).

The EBR-L setup was used to research IR lasers operating on transitions of the Xe and Ar atoms, the basic results of which are shown in Table 3.4.

The high efficiency of the Xe-laser, confirmation of the results of experiments at VNIIEF, as well as the ni > 1 % obtained for the He-Ar laser (A = 1.79 pm), must be considered among the most important results. One should also note the study [37], in which experiments using the EBR-L and IGRIK pulsed reactors determined the energy characteristics for lasers using the mixtures He-Ar (A = 1.79 pm) and He-Ar — Xe (A = 2.03 pm), at high specific energy depositions of up to 2.5 J/cm3. As a result of the investigations, quite high specific output energies were obtained—7.5 J/l at A = 1.79 pm and 9 J/l at A = 2.03 pm.

Some important experiments were recently carried out at VNIITF using the He — Ar-Xe mixture (A = 2.03 pm). These experiments (discussed in reference [34]) demonstrated the maximal energy parameters for NPLs excited using pulsed reactors. The laser output energy was 520 J (output power of 1.3 MW) with an efficiency ni = 3 %. More detailed information is presented later in Chap. 6, Sect. 6.4.