Because the vacuum pump 12 creates {HEAD ~ a vacuum} inside {TAIL ~ the light source chamber} 10, X rays generated and propagating inside the chamber are not attenuated 
inside
Because the vacuum pump 12 creates { HEAD ~ a vacuum } inside { TAIL ~ the light source chamber } 10 , X rays generated and propagating inside the chamber are not attenuated
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH