A SIMPLE FAST PULSE GAS VALVE USING A DYNAMIC PRESSURE DIFFERENTIAL AS THE PRIMARY CLOSING MECHANISM

In this article we describe a simple fast pulse gas valve developed for use in a plasma discharge experiment. The valve delivers 10(17)-10(19) Molecules per pulse varied by changing the voltage on the electromagnetic driver power supply. Valve pulse widths are observed to be less than 300 ps full width at half maximum with a rise time of less than 100 mus resulting in a maximum gas flow rate of approximately 10(22) Molecules per second. An optical transmission technique was used to determine the mechanical opening and closing characteristics of the valve piston. A fast ionization gauge (FIG) was used for diagnosis of the temporal character of the gas pulse while the total gas throughput was determined by measuring the change in pressure per pulse in a small test chamber with a convectron tube gauge. Calibration of the FIG was accomplished by comparing the net change in pressure in a large chamber as measured by the FIG to the net change in pressure in a small test chamber as measured by the convectron tube gauge.