{HEAD ~ The integrity} of {TAIL ~ a beam} of light may be compromised by contamination from other light beams giving rise to “cross talk” 
of
{ HEAD ~ The integrity } of { TAIL ~ a beam } of light may be compromised by contamination from other light beams giving rise to “ cross talk ”
HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH