4  tina83e1-d (2018-12) 
If not indicated otherwise in the legends, the illustrations in this 
document correspond to a MxG50x gauge with FCC receptacle 
and vacuum connection DN 25 ISO-KF. They apply to the other 
products by analogy. 
We reserve the right to make technical changes without prior 
notice. 
 
 
 
  Intended Use 
 
 
Gemini MAG500, MAG504, MAG550, MAG554 
The Cold Cathode Gauges Gemini MAG5xx have been designed 
for vacuum measurement of gases in the pressure range of 
1×10
-9
 … 1×10
-2
 mbar. 
Gauges with gauge identification can be operated in connection 
with an INFICON Vacuum Gauge Controller of the VGC40x / 
VGC50x series. 
 
 
Gemini MPG500, MPG504, MPG550, MPG554 
The Cold Cathode Gauges Gemini MPG5xx have been designed 
for vacuum measurement of gases in the pressure range of 
1×10
-9
 … 1000 mbar. 
They must not be used for measuring flammable or combustible 
gases in mixtures containing oxidants (e.g. atmospheric oxygen) 
within the explosion range. 
Gauges with gauge identification can be operated in connection 
with an INFICON Vacuum Gauge Controller of the VGC40x / 
VGC50x series. 
 
 
 
  Functional Principle 
 
 
Gemini MAG500, MAG504, MAG550, MAG554 
The gauge functions with a cold cathode ionization measure-
ment circuit (according to the inverted magnetron principle).