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Modeling of the positron sources: Experiment-based benchmarking using SuperKEKB

Fahad Alharthi*,†, Iryna Chaikovska, Robert Chehab, and Viktor Mytrochenko

Fusashi Miyahara, Takuya Kamitani, and Yoshinori Enomoto

  • *Contact author: falharthi@kacst.gov.sa
  • †Also at King Abdulaziz City for Science and Technology, KACST, Riyadh, Saudi Arabia.

Phys. Rev. Accel. Beams 28, 111601 – Published 4 November, 2025

DOI: https://doi.org/10.1103/csyg-chyj

Abstract

High-intensity positron sources are critical for next-generation electron-positron colliders, where positron beam quality and characteristics directly impact the luminosity. Accurate modeling and validated simulation tools for positron sources are essential to optimize their performance. However, modeling a positron source tends to be complex, as it involves multiple interdependent stages, from positron production and capture dynamics to beam transport through the injector linac to the collider ring. In this work, we present a start-to-end simulation tool developed for positron sources modeling. The model was benchmarked against existing simulation tools and validated through experimental measurements conducted at the SuperKEKB positron source. Key operational parameters were systematically scanned to evaluate the simulation model performance, including the primary electron impact position on the target, solenoid field strength around the capture linac, and rf phase settings. The primary figure-of-merit for all validation tests was the positron yield at the end of the SuperKEKB positron capture section. Our model reproduces the measured positron yield (0.603±0.003) under nominal operating conditions, with the simulation result of 0.603 lying well within the 0.5% statistical uncertainty. Furthermore, the simulation results demonstrate a very good agreement with experimental data and other simulation tools, confirming the model’s reliability and establishing a framework for future positron source studies.

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