Deuterium ion extraction and neutron production from a piezoelectric transformer plasma source

A piezoelectric transformer plasma source (PTPS) is being developed as a plasma ion source for D(d, n) ³He neutron production. The PTPS consists of a lithium niobate piezoelectric disc in a differentially pumped chamber with controlled gas flow from an external source. The PTPS was previously characterized using a range of gas flows, extraction voltages, and aperture geometries. This ion source has been used for preliminary neutron production measurements using a target at high voltage. Ion current measurements are presented for deuterium gas at PTPS internal pressures from 0.5 to 4 Torr, extraction voltages up to 1.5 kV, and a range of duty cycles and operating times. Ion current yields on the order of 10 μA are presented. The PTPS was also operated with a high voltage D.C. source coupled with a deuterium impregnated palladium foil. Preliminary neutron yields are presented.