Design and Construction of a Multiplate Chamber

Abstract

Multiplate chambers can be used as a source for high current, high voltage ion beams via pseudo-spark discharge. A five gap, untriggered multiplate chamber has been constructed at Houghton College, which operates at voltages up to -25 kV and pressures between 25 and 80 mtorr. The discharge occurs when the voltage across a 2.7 pf capacitor, which is charged through a 400 M? current limiting resistor, reaches the breakdown voltage of the air in the device. The discharge voltage at several operating pressures has been measured by monitoring the current flowing into the capacitor, and the beam current as a function of time has been measured with an oscilloscope across a 10 ? resistor to ground. The shape of the beam spot has been observed using a phosphor screen.