Simulation of surface x-ray emission from the ASTERICS ECR ion source

Area of Science:

• Plasma Physics
• Particle Accelerators
• Radiation Shielding

Background:

• Electron cyclotron resonance ion sources (ECRIS) are crucial for various applications.
• De-confined plasma electrons impacting chamber walls generate bremsstrahlung X-rays.
• Understanding and mitigating this X-ray emission is vital for ECRIS safety and operation.

Purpose of the Study:

• To investigate bremsstrahlung X-ray emission from ECRIS.
• To quantify X-ray dose and its dependence on magnetic field strength (Bmin).
• To design effective shielding solutions for ECRIS.

Main Methods:

• Utilized a suite of two simulation codes for X-ray emission analysis.
• Mapped X-ray dose inside and around the ion source.
• Performed parametric studies using the Fluka simulation code.

Main Results:

• Electron temperature distribution tail at the wall is anisotropic and increases with Bmin.
• Electrons impinge walls with a broad angular distribution (5°-25°).
• X-ray dose without shielding reaches 100 μSv h-1 per kW at 5m; shielding reduces it to <1 μSv h-1 per kW.

Conclusions:

• Anisotropic electron distribution and angular impact influence X-ray emission.
• Effective internal and external shielding designs are presented.
• Simulated heat deposition aligns with experimental findings at specific electron temperatures.