Construction of compact electron storage ring JSR

A compact electron storage ring (JSR) is under construction in order to study accelerator technologies and to be used as the test ring aiming at a highly brilliant synchrotron radiation facility (6--8 GeV). The JSR lattice is a double-focusing achromatic type. The circumference is 20.5 m. However, even in this small ring, one straight section with a length of ∼1.5 m, where the dispersion is free, is provided for the insertion device study. The electron beam is supplied by the linac with an energy of 150 MeV, and the stored energy is slowly increased up to 300 MeV. Power supplies of all magnets and the rf system are controlled by a real-time computer through optical fiber links, and signals of beam monitors are stored in the same computer so that it is easy to test any type of control procedures