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