means for supporting {HEAD ~ a sample} in {TAIL ~ a position} to be illuminated by the infrared radiation in either the transmission mode or the reflectance mode 
in
means for supporting { HEAD ~ a sample } in { TAIL ~ a position } to be illuminated by the infrared radiation in either the transmission mode or the reflectance mode
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 OTH OTH OTH OTH OTH OTH