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