Sensors & Feedthroughs

Front Load Dual Sensor


Product configurator

Gemini™ MxG5xx

Sensor version
Ionization chamber
Emmision current
Flange connection to vacuum chamber
Switching function
Electrical connection
Digital interface
Analog output signal
Your configuration
Gemini™ MxG5xx
Switching functions
Electrical Connection
FCC, 8-pin
Digital Interface
Measurement range
1.2 - 8.68 V
Personal information
Gemini™ MxG5xx
Gemini™ MAG500
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INFICON Front Load Dual crystal sensors offer proven reliability and durability and have the best thermal stability of any sensor head on the market. The dual sensor provides a backup crystal and is essential for critical processes where it is desirable to have the second crystal in the vacuum chamber.

The front load design allows for easy insertion of the crystal holder in applications lacking sufficient room for side insertion. Assembled mechanically rather than soldered, parts can be replaced conveniently in the field, if necessary. Sensors can be ordered individually or in a sensor/feedthrough combination that can be either welded or assembled with compression fittings.


  • Dual crystals
  • Crystal shutter
  • Front load crystal holder
  • Easy installation
  • Available with: 2.54 cm (1 inch) bolt feedthrough and CF40 feedthrough
  • Adjustable length if ordered with compression fittings
  • No brazing required if ordered with compression fittings or welded to feedthrough
  • Sensor/feedthrough combinations available welded to customer specified lengths


Maximum operating isothermal environment temperature with minimum water flow400 ° C
Crystal exchangeFront-loading, self-contained package for ease of exchange. Shutter flips up to ease access to the holders.
Water tubesS-304, 0.125 in. (3.175 mm) OD x 0.015 in. (0.381 mm) Wall thickness seamless stainless steel tubing
Feedthrough Specifications 1 in. bolt and Ultra-Torr (compression fitting) terminations:
Materials304 stainless steel, Teflon, ceramic, beryllium nickel, VITON®
TemperatureOperational environment to 300ºC with water cooling or 165° C without
Mounting1.015 in. ±0.010 in. diameter aperture
Download full specifications


QCM Sensor FeedthroughsQCM Sensor Feedthroughs
Quartz Monitor CrystalsQuartz Monitor Crystals

Spare Parts

Part NumberDescription
007-007Retainer spring (for crystal holder)
007-023Ceramic Retainer
080-018Set screw (for female coax)
082-044Teflon screw (for leaf spring)
750-115-P4Coupling (installs onto bellows assembly)
750-169-P2Bellows assembly (coupling not included)
750-171-P1Finger spring contact
750-172-G1Crystal holder (includes retainer spring)
750-174-P2Female coax
750-175-P1Insulator (underneath leaf spring)
750-188-P3Leaf Spring
750-210-G1Shutter module (bellows assembly, shaft assembly, and shutter assembly)
750-215-G1Shaft assembly (part of shutter module)
750-216-G1Shutter assembly (part of shutter module)
In-vacuum cables 
321-039-G12In-vacuum cable, 15.2 cm (6 in.)
007-252In-vacuum cable, 30.5 cm (12 in.)
321-039-G11In-vacuum cable, 61.0 cm (24 in.)
007-044In-vacuum cable, 78.1 cm (30.75 in.)
007-059In-vacuum cable, 91.4 cm (36 in.)
007-061In-vacuum cable, 121.9 cm (48 in.) - Requires ModeLock controller
321-039-G13In-Vacuum Cable, 154.2 cm (60 in.) - Requires ModeLock controller
321-039-G14In-vacuum cable, 182.9 cm (72 in.) - Requires ModeLock controller
321-039-G15In-vacuum cable, 3.5 m (137.8 in.) - Requires ModeLock controller and 4 m XIU
321-039-G16In-vacuum cable, 4 m (157.5 in.) - Requires ModeLock controller and 4 m XIU

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