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