Thus, at the start of laser oscillator 1, an anomaly of the gas composition can be discriminated at {HEAD ~ a plurality} of {TAIL ~ arbitrary low pressures}, and the reliability of the discrimination method can be thereby improved 
Thus , at the start of laser oscillator 1 , an anomaly of the gas composition can be discriminated at { HEAD ~ a plurality } of { TAIL ~ arbitrary low pressures } , and the reliability of the discrimination method can be thereby improved
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH