The discrimination of {HEAD ~ an anomaly} of {TAIL ~ gas composition} of the laser gas can be accomplished by simple means 
of
The discrimination of { HEAD ~ an anomaly } of { TAIL ~ gas composition } of the laser gas can be accomplished by simple means
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH