{HEAD ~ vacuum} means enclosing at least the chip and said {TAIL ~ luminescent target} means  
enclosing
{ HEAD ~ vacuum } means enclosing at least the chip and said { TAIL ~ luminescent target } means
HEAD HEAD HEAD HEAD HEAD OTH REL OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH