5 - 1
Transpector XPR 3+ Operating Manual
Chapter 5
Transpector XPR 3+ Operation and Best Known 
Methods
5.1  Introduction
Once the Transpector XPR 3+ Sensor, Electronics Module, Isolation Valve, and 
Pirani Interlock are installed, the isolation valve should be opened to allow 
Transpector XPR 3+ to obtain high vacuum. It is strongly recommended that 
Transpector XPR 3+ be kept under high vacuum conditions for at least eight hours 
before the filament is turned on. It is also recommended that Transpector XPR 3+ 
be baked out with the supplied heating jacket (which operates at 150 °C), for a 
period of at least eight hours. This eight hour minimum bakeout is required to 
reduce residual water vapor levels that may be higher due to local surface 
outgassing effects. These recommendations should be followed whenever 
Transpector XPR 3+ Sensor is exposed to atmosphere for long periods of time and 
will serve to increase sensor life.
Do not turn on electron multiplier high voltage at sensor 
temperatures above 150 °C. Permanent damage to the 
electron multiplier could result.
During or immediately after bakeout, the heating jacket 
and metal surfaces in the vicinity of the heating jacket 
may be hot. These surfaces may exceed 100 °C at the 
maximum ambient operating temperature (i.e., 50 °C), 
which will cause burns if touched directly without using 
the proper personal protection equipment.
Table 5-1  Transpector XPR 3+ Sensor maximum bakeout temperature
Sensor
Maximum
Operating
Temperature
Maximum Bakeout 
Temperature
Electronics Removed
Transpector XPR 3+ 150 °C 200 °C