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