Connected to {HEAD ~ the light source chamber} 10 is {TAIL ~ a vacuum pump} 12; hence, the light source chamber 10 is a vacuum chamber 
Connected to { HEAD ~ the light source chamber } 10 is { TAIL ~ a vacuum pump } 12 ; hence , the light source chamber 10 is a vacuum chamber
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH