Fast Gas Injection System

Gas Injector
Gas Injector

The General Atomics fast gas injection system is designed for injecting short (millisecond or longer) pulses of nonreactive gases into a vacuum system. The level of flow is measured with a small pressure sensor and the flow is feedback regulated so that the actual flow matches the demand.

Originally developed for fusion research devices, the piezoelectric valves and pressure sensors can be used in large magnetic fields. They are made of completely nonmagnetic materials and have been used in magnetic fields up to 2.4 T.



  • piezoelectric gas injection valve
  • flow rate up to 500 torr-liter/s
  • opening time: 2 ms after application of voltage
  • flow measured by pressure sensor mounted on valve
  • valve and pressure sensor insensitive to DC magnetic fields
  • gas pressure up to 6.5 atm (absolute)
  • gas input: miniconflat flange
  • mounting: 2 3/4 inch conflat flange
  • alternate vacuum flanges available



  • controls up to 4 gas injectors through individual plug-in modules
  • local manual control or external voltage programming for each control module
  • voltage control in range of 0-10 V
  • 0-10 V analog output from pressure (flow) sensor on each valve
  • adjustable voltage waveform to match characteristics of various piezoelectric valves
  • up to 30 meter cable lengths to valves



  • Doublet IIA, Doublet III, DIII-D at GA

  • ISX-A, ISX-B at ORNL 

  • TEXTOR at IPP Jülich 

  • ASDEX-Upgrade , Wendelstein 7AS at MPI Garching, Germany

  • ZT-40 at LANL

  • KSTAR at NFRI, South Korea

  • Wendelstein 7X, MPI, Greifswald, Germany

Prices vary according to system configuration, interface requirements and shipping costs.


Representive prices (March, 2001):

  • One valve controller, one valve control module, and one valve: $48,000.
  • One valve: $11,500. For orders of more than one valve, the price per valve will drop and will depend on the number of valves.
  • Additional valve control modules (the controller has room for 4): $6,500.