In one form the detected photoluminescence is compared to {HEAD ~ detected scattered excitation light} to determine {TAIL ~ temperature} 
In one form the detected photoluminescence is compared to { HEAD ~ detected scattered excitation light } to determine { TAIL ~ temperature }
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL