A research paper on laser technology for the Fast Abort system, led by Shunya Kitada, who graduated from our laboratory this spring, has been published in the international journal Optics and Lasers in Engineering.

In this study, Shunya Kitada and researchers from KEK and CERN conducted a long-distance laser propagation experiment using the klystron gallery of the KEK Linear Accelerator (Linac), achieving a propagation distance of 420 m. The experiment employed a structured laser beam (SLB) with a Bessel-like profile to investigate how the optical power concentrated in the central region of the beam changes depending on the laser generation parameters and illumination strategy after long-distance propagation. The results demonstrated that controlling the beam energy distribution can enhance the concentration of optical power in the central region by more than a factor of three. This study represents an important step toward the realization of high-precision long-distance laser transmission technologies, including applications in the Fast Abort system for the SuperKEKB accelerator.

Paper information:
Martin, D., et al. "Tailoring the power distribution of long-distance propagating Bessel-like structured laser beams via selective illumination"
[Optics and Lasers in Engineering, Volume 206 (2026), 110025. DOI: https://doi.org/10.1016/j.optlaseng.2026.110025]

Kitada-san is doing laser alignment work in the LINAC gallery,

communicating via PHS while having the alignment fine-tuned at the other end of the laser.