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