Temperature sensors, such as pyrometers, that do not contact the wafers being preheated, measure {HEAD ~ temperature} for {TAIL ~ control} of the heating of the lamps 
Temperature sensors , such as pyrometers , that do not contact the wafers being preheated , measure { HEAD ~ temperature } for { TAIL ~ control } of the heating of the lamps
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH