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