Speaker
Description
Negative helium ion sources are typically required for tandem accelerators where they are mostly used for materials analysis in the form of Rutherford backscattering spectrometry (RBS). As alkaline metal vapor is required for charge conversion of the positive ion beam to negative – with conversion rates < 2%, these type of He- ion sources tend to have limited beam intensity and maintenance lifetimes.
The work done in the Accelerator Laboratory of the University of Jyväskylä targets to develop a commercially available negative helium ion source where long life-time maintenance interval and up to 20 uA He- beam should be reached. This setup is based on the permanent magnet plasma chamber driven with the 2.45 GHz microwave RF-source from the ground potential. These design choices require only a small power consumption at the high voltage potential, enabling also a small footprint.
The extraction energy was originally targeted for the 5-7 keV, being optimal for the Rubidium based charge exchange, but it now seems obvious that to reach > 1mA positive beam, 10 or up to 15 keV extraction energies will be needed.
This presentation will go through the background, design and current status of the work as well as the existing problems of the permanent magnet design which causes issues in the extraction region.
| Email address | mikko.i.laitinen@jyu.fi |
|---|---|
| Visitor's Visa | no |
| Classification | Other negative ion sources for fusion, accelerators, and other applications |