The sensor 3, wherein the detection head further comprises second laser means for heating {TAIL ~ the sample} to volatilize {HEAD ~ the sample} 
The sensor 3 , wherein the detection head further comprises second laser means for heating { TAIL ~ the sample } to volatilize { HEAD ~ the sample }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD