A construction and exploitation of a comparatively large I photodissociation laser system (Perun) is reported. This system was constructed in cooperation between the Institute of Physics of Czechoslovak Academy of Science in Prague and the Lebedev Institute of Physics of Soviet Academy of Science in Moscow. The laser produces subnanosecond pulses of maximum 50 J and 0·5 ns in duration. Although the pumping time by Xe flashlamps is long enough for an acoustic disturbance released in the active medium to introduce an optical inhomogeneity across the whole cross section of the laser tube, the radiation can be focused in a focal spot of a power density exceeding 1014 W/cm2, enough for meaningful laser target experiments both for a laser plasma production or a modification of solid surfaces. The repetition time of the shots is about 10 min.