Status of R&D efforts toward the ERL-based future light source in Japan

The Energy Recovery Linac (ERL) is a very promising synchrotron light source in future. We are contemplating to realize an ERL-based next-generation light source in Japan, under a collaboration between KEK, JAEA, ISSP, and other SR institutes. To this end, we started R&D efforts on its key technologies, including a low-emittance photocathode gun and superconducting cavities. We also plan to assemble these technologies into a small test ERL, and to demonstrate their operations. We report our R&D status.