H− temperature dependences in a Penning surface-plasma source

Abstract

Simple analysis of the nearly Maxwellian angular distributions of the ribbon H− ion beams extracted from a long, narrow slit on the 8X source yields the H− temperature, kTH−. The derived kTH− are 0.1–0.3 eV for a 2-A dc discharge and 0.7–1.3 eV for a 400-A pulsed discharge. Because this diagnostic method relies on simple electronic techniques, it allows rapid study of the dependences of kTH− on the source parameters, such as gas flow and discharge current. These variations of kTH− in the 8X source are qualitatively similar to those observed for the H-atom temperature, kTH0, in the 4X source, another Penning surface-plasma source.

Negative hydrogen ion sources for accelerators

“…The units of are the spatial unit of (usually millimeters or centimeters) and radians. At least two measurement types for have been made on accelerator sources: first, volume production [29]- [31] using a two-laser photodetachment technique; and second, the SPS Penning source [32], [33] equipped with a long emission slit and measurement of the extracted angle distribution in the orthogonal plane with an electric sweep scanner [27]. In the case of the photodetachment technique used in volume production, two distributions corresponding to cold and hot temperatures are found.…”