Cesiation in highly efficient surface plasma sources

Abstract

Novel modifications of H À =D À source designs have been proposed. New sources under development include advanced versions of a compact surface plasma source which will efficiently generate brighter beam in noiseless discharge, deliver significantly increased (up to 20 mA) average current with better electrode cooling using new materials, and have significantly extended lifetime, fast beam chopping capability, and reduced cesium loss. Related ion sources that use cesium are described and an improved cesiation procedure for reproducible production of high efficiency H À ion generation is considered.

Pulsed DC bias for the study of negative-ion production on surfaces of insulating materials in low pressure hydrogen plasmas

“…When alkali metal surfaces such as cesium (Cs) are in contact with plasma, a huge surface production of NI by conversion of positive ions or atoms is observed 3 . This effect is the basis of the most intense H − /D − negative ion sources developed for fusion or particle accelerator applications 4,5,6,7 . However, the presence of cesium inside negativeion sources complicates their operation and alternative solutions to produce high rate of negative ions on surfaces in contact with hydrogen plasma would be valuable.…”

Perspective for development of a universal source of highly polarized ions

“…The probability of negative ion emission from a cesiated surface bombarded by plasma ions and atoms strongly depends on the surface work function (φ) as shown in Fig. 7 [16]. It is very important to keep the surface WF as low as possible.…”

Forty-five years with cesiated surface plasma sources

“…One practical result of the development of high brightness surface plasma negative ion sources with cesiation (SPS) [1,2,3,4,5,6,7] is the wide use of charge-exchange injection in circular accelerators for routine operation [8,9,10]. Now, SPS's are "working horses" for large accelerator complexes at ORNL (SNS Spallation Neutron Source, Oak Ridge National Laboratory), FNAL (Fermi National Accelerator Laboratory), LANSCE (Los Alamos Neutron Science Centre), BNL (Brookhaven National Laboratory), RAL (ISIS proton synchrotron at the Rutherford Appleton Laboratory), DESY (Deutsches Elektronen-Synchrotron), KEK/J-PARC (Japan Proton Accelerator Research Complex).…”