{TAIL ~ Fluorescent emission} generally occurs in a time frame of {HEAD ~ less than 10 nanoseconds} 
{ TAIL ~ Fluorescent emission } generally occurs in a time frame of { HEAD ~ less than 10 nanoseconds }
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD