5
Introduction
The GR020 pulse valve is designed to precisely inject gas in a vacuum chamber. Both the timing
and the amount of gas released can be finely tuned.
Applications:
- High Order Harmonic generation
- Attophysics
- Molecular alignment
- Cluster science
- Electron spectrometers
- Gas phase spectroscopy
Principle of operation
The pulse valve is driven by a piezo electric disc (PZD) on which a small poppet is tightened. It
opens and closes a 1 mm diameter hole where thhe gas flows. The moving parts are kept as light
as possible, which makes opening times as short as 30
μ
s feasible.
The PZD and the poppet are
mounted inside the valve body where backing pressures up to 5 bars can be applied. The valve
opens when applying a voltage to the PZD and the backing gas flows in the 1 mm pipe through
the body. The amount of gas is controlled by the voltage applied to the PZD. At the end of this
pipe the target is tightened to the body by two screws. The target is decoupled from the moving
parts; this makes the switch between targets very easy, and allows for custom-made target
designs. The valve can is driven by a voltage gate produced by our piezo valve drive unit,
together with a delay generator, or other pulsed high voltage power supplies. A 120
μ
s electrical
gate corresponds to a mechanical opening time down to 30
μ
s.*
The body of the valve is cooled by a water cooling circuit.
The opening time is estimated from how much the valve-trigger must be temporally detuned
from a laser pulse to completely cancel the high harmonic yield from the laser-gas-interaction.