[Triumf-seminars] TRIUMF Seminar today at 14:00

Wed, 17 Aug 2005 05:00:00 -0700

---------------------- multipart/mixed attachment
Date/Time: Wed 2005-08-17 at 14:00

Location:  Auditorium          

Speaker:   Yong-Seok Hwang (Dept. of Nuclear Engineering, Seoul National Univ.)

Title:     Characterization of TRIUMF DC H- ion sources for enhanced brightness

Abstract: A robust high-current dc H- ion source has been developed at TRIUMF and is operational in cw mode in several cyclotrons around the world. Optimizing filament configuration, vacuum, cusp confinement, electron filtering and extraction geometry led to strong performances such as high cw beam current, brightness, good power efficiency and low e/H ratio.[1] Extensive further studies have begun to understand the physics of H- ion source as well as to improve the TRIUMF source, especially in terms of brightness. 

In this talk, the H- ion sources existing at TRIUMF are characterized to elucidate how they perform. Measured beam characteristics such as current, emittance and e/H ratio are presented and correlated with various source conditions in function of relevant plasma parameters. Beam characteristics were also simulated with the PBGUNS code and compared with experimental data. Plasma densities, temperatures and plasma potential will be discussed. Performances at different confining magnetic fields, arc powers, and neutral gas pressures are presented. Beam extraction is studied for different filtering fields and extraction systems. Pressure distributions along the beam path from the plasma source chamber to the diagnostic box are changed separately to see effects of beam stripping and charge neutralization independently of operating pressure of the source chamber. Experiments such as collar biasing and noble gas mixture were attempted and will be discussed.

References

[1] T. Kuo et al., 1996, Rev.Sci.Instrum. 67(3), 1314-1316, (March 1996).

Stimulants available 15 minutes before the talk.

______________________________

Subscription information available at http://admin.triumf.ca/netdata/seminars/list

---------------------- multipart/mixed attachment--