Investigation of the threshold of formation of a plasma screening radiation in a spatial filter

An experimental investigation was made of the formation of a plasma in the evacuated interior of a spatial filter containing a metal stop. An estimate was obtained of the plasma formation threshold at which the filtered radiation of a CO₂ electron-beam-controlled laser was screened. This effect appeared already after 5 μsec from the beginning of lasing when the edge of the stop was irradiated with a pulse characterized by an energy density exceeding 500 J/cm².