The apparatus 4, further comprising an ion gauge installed along said processing line between {TAIL ~ said processing chamber} and a point where said bypass line branches from {HEAD ~ said processing line} 
The apparatus 4 , further comprising an ion gauge installed along said processing line between { TAIL ~ said processing chamber } and a point where said bypass line branches from { HEAD ~ said processing line }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD