The X rays are emitted in {HEAD ~ response} to {TAIL ~ an impinging beam}, such as an electron beam, directed towards the sample surface where a defect resides 
to
The X rays are emitted in { HEAD ~ response } to { TAIL ~ an impinging beam } , such as an electron beam , directed towards the sample surface where a defect resides
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH