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  • Open Access

Cryogenic buffer gas beam source with in situ ablation target replacement

Zhen Han1,*, Zack Lasner2,3, Collin Diver4, Peiran Hu1, Takahiko Masuda5, Xing Wu6, Ayami Hiramoto2,4,5,3, Maya Watts4, Satoshi Uetake5 et al.

Koji Yoshimura5, Xing Fan4,2,3, Gerald Gabrielse4, John M. Doyle2,3, and David DeMille1

  • *Contact author: zhenhan@uchicago.edu
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APS Open Sci. 1, 000016 – Published 4 May, 2026

DOI: https://doi.org/10.1103/3qhm-yr7d

Abstract

The design and performance of a cryogenic buffer gas beam source with a load-lock system is presented. The third generation of advanced cold molecule electric dipole moment search (ACME III) uses this source to produce a beam of cold, slow thorium monoxide (ThO) molecules. A feature of the apparatus is the capability of replacing the ablation targets without interrupting the vacuum or cryogenic conditions, thus increasing the average signal in the eEDM search. The beam source produces 1.3×1011 ground-state ThO molecules per pulse on average, with rotational temperature of 4.8K, molecular beam solid angle of 0.31sr, and forward velocity of 200ms−1, parameters that are consistent with the performance of a traditional source (without a load lock) requiring time-consuming thermal cycles for target replacement. Long-term yield improvement of ∼40% is achieved when the load-lock system is employed to replace targets every two weeks.

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Outline

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APS Open Sci. 1, 000016– Published 4 May, 2026
Vol. 1
  • Received 25 February 2026
  • Revised 13 April 2026
  • Accepted 15 April 2026
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

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