Magnetostatic Modelling and Measurement for Particle Dynamics of a Magnetic Energy Filter

This thesis discusses the modelling and measurement of electromagnetic fields in a filter designed to selectively filter low-energy electrons from beams produced by electron sources. Two electron source configurations—based on a direct current (DC) 0.5 MeV electron gun and a 3.5 MeV radio frequency (RF) electron gun available at the Canadian Light Source (CLS) test laboratory—were examined. Magnetostatic simulations were conducted using two-dimensional modelling software, and the results were validated against experimental measurements using a magnetic energy filter system at CLS. This process enabled the calibration of magnetic field settings for optimized performance in the test laboratory. The primary settings of interest were calculated, which are the operating currents needed for each of the magnets within. Particle tracking software was subsequently employed to simulate a beam of electrons traversing the energy filter, allowing for the generation of trajectory plots and evaluation of the momentum spread before and after filtration. The calculated operating parameters for the magnetic filter were as follows: for the DC electron gun, the dipole magnets required a current of 0.697 A, while the entrance and exit focusing quadrupoles operated at 0.195 A, the center focusing quadrupole at 0.229 A, and the defocusing quadrupoles at −0.256 A. For the RF electron gun, the dipole current was found to be 4.88 A, with the corresponding quadrupole currents at 1.37 A, 1.61 A, and 1.80 A. Both configurations successfully achieved a reduction in the momentum spread by eliminating low-energy electrons; however, the RF setup allowed substantially higher beam current densities, up to 9.14 A/mm2. Overall, the findings demonstrated that the modelled filter effectively refined the electron beam qualities for both electron guns. The methodology was shown to be adaptable to other sources with beam energies below 11.9 MeV, within the linear operating range of the model.

Name thesis:degree_name

Master of Science (M.Sc.)

Level thesis:degree_level

Masters

Discipline thesis:degree_discipline

Physics

Grantor

University of Saskatchewan

Year dc:date.issued

2025

Author dc:creator

• Shomachuk, Terryl

Advisor dc:contributor.advisor

• Boland, Mark

Committee members dc:contributor.committeemember

• Xiao, Chijin
• Xiaodong, Liang
• Toohey, Mathew

• Accelerator
• Electron
• Synchrotron
• Beam Dynamics
• Simulation
• Momentum Filtering

Language dc:language.iso

en

Handle dc:identifier.uri

https://hdl.handle.net/10388/17262

OAI identifier oai:identifier

oai:harvest.usask.ca:10388/17262