Fast Gas Valves

Alameda Applied Sciences offers a high-speed gas valve that operates on the principle of a conductive flyer plate accelerated by eddy currents induced by an adjacent coil. The low-mass flyer plate and backing spring combination provide a fast opening (<100 μs) and closing (<500 μs) time for the valve. Other commercially available solenoid valves typically open in 1 ms and close in several ms. In one embodiment of the AASC valve, a nozzle structure directs a supersonic flow of gas into a rectangular jet of high-density gas suitable for interaction with a laser beam transverse to the jet, for the production of laser wake-field interaction, leading to very high-energy electrons from the gas jet.

AASC builds valve drivers and custom gas manifolds to support our valves. We have designed a rep rated driver for our single plenum valves that is operational at up to 10 Hz. Our multiple plenum valve drivers operate in single shot mode. Each valve plenum can be fired independently.

Applications

Numerous emerging fields require an electrically controlled gas valve with faster response time.

  • Laser wake-field acceleration (LWFA) provides electron accelerators with unprecedented electric field gradients. Supersonic and highly collimated gas jets, or gas-filled capillary discharge waveguides are two primary targets of choice. Present gas jets have lengths of <4 mm at densities of 1-4x1019 cm-3, sufficient for electron acceleration to energies up to 150 MeV. A well collimated beam that is ≥10 mm in length and with the ability to tailor the gas density profile to optimize the LWFA process would further improve LWFA performance.
  • In flash x-ray machines, a supersonic shell of gas is compressed by high currents and forms a dense, hot plasma pinch that radiates the desired x-rays in a short burst. Photo at left shows one such valve/nozzle delivered by AASC to the DoD and to the French DGA.
  • In other accelerators, it is sometimes desirable to inject a metered pulse of gas into a beam-line or test cell. One difficulty in the prior art is the requirement for precise control of the mass injected so that only the region of interest is filled with gas, while the rest of the accelerator structure can remain at high vacuum. For this application, the gas burst must be fast enough so that a high vacuum event may occur before the injected gas reaches the high vacuum region to perturb it.
  • The AASC fast valve might also be used to inject non- conducting liquids or high-pressure gases for automotive or other applications.

Specifications

AASC’s fast gas valves can be tailored to the customer's desired operating pressure and gas jet density. The rapidly closing valves allow operation at high repetition rates (10-100Hz), even at 1500 psia plenum pressure.

  • A rep rated driver for our single plenum valves is operational at up to 10 Hz.
  • Our multiple plenum valve drivers operate in single shot mode. Each valve plenum can be fired independently.
Features of the manifolds include:
  • Standard 19” rack mount enclosure.
  • Controls accessible from the front panel.
  • Both local and remote control of solenoid valves.
  • Three solenoid valves for each plenum control gas fill, pump out and vent out independently.
  • Local pressure readout for each plenum and a signal output from the pressure transducers.
  • Overpressure protection on each line.