Performance of the LBL AECR source at various frequencies
To study the effects of frequency on an electron cyclotron resonance (ECR) ion source, the LBL Advanced ECR ion source (designed to operate at 14 GHz) has been tested at 6.4, 10, and 14 GHz with one plasma chamber (ID = 6.0 cm), a permanent sextuple magnet (``closed sextuple``) with a field strength of 0.84 Tesla at the chamber wall, and no radial vacuum pumping. Pure oxygen was used as the running gas for a fair comparison. The source was tested as a single stage, as well as with cold electron injection using an electron gun in place of a conventional microwave-driven first stage. Higher frequency, with a higher axial magnetic field to ensure a closed ECR zone for electron heating, does give better performance. As demonstrated before, at each frequency electron injection led to about a factor of two increase in the high charge state oxygen beam intensity. The 14 GHz performance of the AECR source with the closed sextuple magnet was compared to the ``slotted sextuple`` (a plasma chamber with radial pumping slots of 7.0-cm dia and a weaker magnet of 0.64 Tesla at the chamber wall). Results show that a stronger sextuple magnet alone does not automatically improve the source performance.
- Research Organization:
- Lawrence Berkeley Lab., CA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 10183868
- Report Number(s):
- LBL-32680; CONF-920741-5; ON: DE93000634
- Resource Relation:
- Conference: 13 international conference on cyclotrons and their applications,Vancouver (Canada),6-16 Jul 1992; Other Information: PBD: Jul 1992
- Country of Publication:
- United States
- Language:
- English
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