rf driven multicusp H− ion source

Abstract

An rf driven multicusp source capable of generating 1-ms H− beam pulses with a repetition rate as high as 150 Hz has been developed. This source can be operated with a filament or other types of starter. There is almost no lifetime limitation and a clean plasma can be maintained for a long period of operation. It is demonstrated that rf power as high as 25 kW could be coupled inductively to the plasma via a glass-coated copper-coil antenna. The extracted H− current density achieved is about 200 mA/cm2.

Negative hydrogen ion production mechanisms

“…From this compact source, an H À current density greater than 250 mA/cm 2 has been extracted. 139 In 1991, Leung et al 140 reported the development of an RF-driven H À ion source at LBNL for use in the superconducting super collider. In a later publication, Leung 141 presented the advantages of the RF-driven source over the dc filament discharge source:…”

High-yield D–T neutron generator

“…In recent years continuously pumped D-D generators, which use radiofrequency (RF) driven ion sources [7] for generating high beam currents and beam-loaded Titargets [6], have been developed at the Lawrence Berkeley National Laboratory (LBNL) [8,9].…”

Record performance of and extraction studies with the Spallation Neutron Source H− injector

“…Employing a magnetic filter to reduce the electron temperature near the outlet made filament driven Tandem sources more competitive in 1982 [12]. Introducing a Cs collar and replacing the filament with an RF driven antenna in 1990 promised to overcome the lifetime limitation of filaments [13]. For significant average plasma powers, the antennas need to be water-cooled and electrically isolated from the conductive plasma.…”

“…For significant average plasma powers, the antennas need to be water-cooled and electrically isolated from the conductive plasma. LBNL developed antennas that featured only a single, thin layer of porcelain [13], which kept failing at high plasma powers [14,15]. Listing six reasons why internal antennas could never work reliably [16], DESY developed an external antenna source that was very successful at low duty cycles, but was never used for production [17].…”