{TAIL ~ Use} of a transparent lens would unavoidably create rear surface reflection of the incoming radiation, which would mix with the sample reflected radiation traveling toward {HEAD ~ the detector} 
{ TAIL ~ Use } of a transparent lens would unavoidably create rear surface reflection of the incoming radiation , which would mix with the sample reflected radiation traveling toward { HEAD ~ the detector }
TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH 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