Possibility of protecting a mirror of a laseron the 4d — 4p transitions of nickel-like tantalum ionsagainst spontaneous X-rays by means of a filter

The possibility of protecting a mirror of a laser on the 4d — 4p transitions of nickel-like tantalum ions against spontaneous X-rays by means of a carbon or potassium filter is considered. It is shown that such filters can transmit 75% — 80% of laser radiation at 44.83 Å, attenuating at least by half the intensity of radiation incident on the mirror in other spectral regions, which considerably suppresses the double-pass amplification.