The Round to Flat Beam Transformation (RFBT) is one of the emittance exchange techniques that can improve the Luminosity for the future accelerator project International Linear collider (ILC). RFBT experiment can be conducted in the KEK-STF, and the expected performance is 334 in emittance ratio. In December 2023, we performed a pilot experiment at STF to optimize the injector conditions. To improve the RF Gun of STF, we applied dry ice cleaning to reduce the field emission. The field enhancement factor was improved from 233 to 100.

The Round to Flat Beam Transformation (RFBT) is one of the emittance exchange techniques that can improve the Luminosity for the future accelerator project International Linear collider (ILC). RFBT experiment can be conducted in the KEK-STF, and the expected performance is 334 in emittance ratio. In December 2023, we performed a pilot experiment at STF to optimize the injector conditions. To improve the RF Gun of STF, we applied dry ice cleaning to reduce the field emission. The field enhancement factor was improved from 233 to 100.

Two synchrotron radiation sources, the 2.5 GeV Photon Factory Storage Ring (PF ring) and the 6.5 GeV Photon Factory Advanced Ring (PF-AR), have been in stable operation at the High Energy Accelerator Research Organization (KEK) for over 40 years. This paper first describes the current operational status and recent developments at PF. Next, a new concept of hybrid light source (PF-HLS) combining the advantages of a superconducting linac and a low-emittance storage ring is described. In the preliminary design, the energy range is from 2.5 GeV to 5.0 GeV, and the storage ring will be constructed in a green field with a circumference of 750 m. The design baseline for superconducting linac uses the International Linear Collider (ILC) specifications.

GaAs cathodes are unique devices which generate a spin-polarized electron beam by the photoelectric effect when illuminated with a circularly polarized laser. Thin-film Negative Electron Affinity (NEA) surfaces have an essential role in spin polarized beam production, but they have limited lifetimes. In this study, we activate GaAs as an NEA cathode by evaporating Cs, Cs-O, and Sb metal on its cleaned surface. Here we present the latest experimental results of quantum efficiency measurements taken after evaporative deposition of multi-alkali thin-film surfaces.