a first focusing reflector which directs source provided {HEAD ~ radiation} to {TAIL ~ the sample} in the transmission mode 
to
a first focusing reflector which directs source provided { HEAD ~ radiation } to { TAIL ~ the sample } in the transmission mode
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH