Speaker
Description
Third-generation electron cyclotron resonance (ECR) ion sources utilize superconducting magnets to achieve the enhanced plasma confinement necessary to produce intense, highly-charged ion beams. However, since plasma density increases proportionally with the square of resonance frequency, the higher radiofrequency (RF) and higher power used to heat the plasma produce a greater number of very energetic electrons, which are the source of the bremsstrahlung emission that poses a significant thermal load to the 4 K liquid helium cryostat. Because traditional plasma diagnostics are destructive, we analyze non-invasive axial bremsstrahlung emission from the hot electrons, ascribing a spectral temperature to the measured spectrum under varying magnet, vacuum pressure, and RF parameters. The work presented here confirms previous measurements and investigates effects on charge state distributions, x-ray emission properties, and cryostat heat load. Extrapolating the electron heating this way will also inform the heat shielding design for the fourth-generation MARS-D ECR ion source.
| Classification | MC3: Fundamental processes and plasma studies |
|---|---|
| I have read and accept the Privacy Policy Statement | Yes |