Framework automates pit detection in CR-39 detectors for laser-driven ion research

Laser-driven ion acceleration offers compact, ultrashort-duration particle sources for applications ranging from medical therapy to inertial confinement fusion research. Detectors using polymers of allyl diglycol carbonate, called Columbia Resin-39 (CR-39), form microscopic pits that have been etched by laser-driven ion beams. These detectors provide high spatial resolution and absolute particle detection with high sensitivity, but analyzing the pits to characterize the beams has traditionally been a slow and labor-intensive manual process.

Lin et al. have developed an automated framework for pit detection in CR-39 detectors from two-dimensional optical micrographs. Drawing on Monte Carlo simulations of restricted energy loss and integrating detected pit shapes into a pit-formation model, the group’s approach provides a faster, more reliable method to characterize laser-driven proton beams.

“The key innovation is that our method provides a complete and automated analysis pipeline while preserving the angular information contained in the elliptical pit shapes,” said author Chih-Hao Pai. “By providing accurate and automated characterization of laser-driven ion beams, the framework can significantly improve experimental throughput and enable larger datasets to be analyzed consistently.”

While prior automated approaches have focused on counting particles or estimating pit sizes, the group’s framework simultaneously extracts pit geometry with high precision and converts these measurements into both energy and angular information.

They compared its performance to a manual tracing approach, which exhibited higher subjective variability with pit size standard deviations up to 9.4%. The automated algorithm produced consistent results across repeated analyses.

The framework’s computational efficiency and support for GPU acceleration make it scalable for a broad range of ion-beam diagnostics and spectroscopy.

The group plans to apply the framework to laser-driven proton acceleration experiments and laser-assisted proton-boron fusion studies, where rapid and reliable beam characterization is essential.

Source: “Automated CR-39 pit detection for energy and angular characterization of laser-driven ion beams,” by Wei Lin, Tzu-Yao Huang, Shih-Fan Yang, Shih-Wei Wang, Wu-Cheng Chiang, Kuo-Yu Hsiao, Chun-Han Chen, Yan-Syu Liu, Jun-Yi Chen, Ya-Po Yang, Chen-Kang Huang, Hsu-hsin Chu, and Chih-Hao Pai, AIP Advances (2026). The article can be accessed at https://doi.org/10.1063/5.0338529 .