Radiation Physics and Engineering
A peer-reviewed journal published by K. N. Toosi University of Technology

COMSOL simulation study of electrostatic quadrupole doublet field characteristics in the ES-200 accelerator

Document Type : Research Article

Authors

Mohammad Mahdi Mansouri Hasanabadi 1
Hamidreza Mirzaei 2

1 Radiation Application Department, Shahid Beheshti University, G.C, Iran‎

2 Department of Physics and Accelerators, Nuclear Science and Technology Research Institute (NSTRI), P.O. Box 14395-836, Tehran, Iran

https://doi.org/10.22034/rpe.2026.572709.1336
Abstract
This work presents a systematic optimization of an electrostatic quadrupole (ESQ) doublet designed for the ES200, a 200 keV Cockcroft-Walton ion accelerator through high-fidelity COMSOL Multiphysics simulations. The study aims to enhance beam focusing performance by rigorously analyzing critical field characteristics, including field linearity, electric potential distribution, and fringe field effects. Aperture diameters ranging from 30 mm to 70 mm were evaluated while maintaining a fixed electrode radius of 22 mm, consistent with mechanical and electrical constraints. The optimized configuration, featuring a 50 mm aperture, demonstrated superior field linearity with a minimal relative deviation of 0.8% at a 10 mm radial distance, ensuring uniform focusing forces across the beam profile. Furthermore, the implementation of integrated shielding discs and a structural support frame resulted in a 37.5% reduction in fringe field leakage, thereby improving field confinement and overall beam stability. These findings provide a validated design framework for fabricating a high-performance ESQ doublet, contributing to enhanced beam quality and operational reliability in compact, low-energy ion accelerator systems.

Highlights

  • This study employs COMSOL Multiphysics to systematically optimize an electrostatic quadrupole (ESQ) doublet.
  • An aperture size of 50 mm with 22 mm electrode radius was identified as the optimal configuration.
  • Integration of shielding discs and a structural frame resulted in a 37.5% reduction in fringe field leakage.
  • The study demonstrates a simulation design approach that balances electrical performance with mechanical constraints.
  • The optimized ESQ doublet contributes to improved beam quality and focusing precision.

Keywords

Electrostatic
Quadrupole
ESQ doublet
Ion accelerator
Beam focusing
COMSOL simulation
ES200

Copyright
RPE is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License (CC BY-NC 4.0).

Conflict of Interest
The authors declare no potential conflict of interest regarding the publication of this work‎.

Funding
‎The authors declare that no funds‎, ‎grants‎, ‎or other financial support were received during the preparation of this manuscript‎.

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Radiation Physics and Engineering
Volume 7, Issue 3
Summer 2026
Pages 39-44

  • Receive Date 29 January 2026
  • Revise Date 13 June 2026
  • Accept Date 18 June 2026

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