Design of the septum magnet for S-LSR

At the end of September 2005, we completed the construction of Small Laser-equipped Storage Ring (S-LSR) in Institute for Chemical Research, Kyoto University, and 1 week later, we succeeded in the beam accumulation of 7-MeV proton. In S-LSR, the injection and extraction system were placed in the same straight section 1.86 m in length, so the compact septum magnets were needed. The pole length of septum magnet was determined 30 cm by space limitation. And the bending angle of 0.7 rad is to be realized with the magnetic field of 0.8 T for 7 MeV proton beam. The gap of pole is 35 mm. The shield was designed to suppress the leakage field less than 2 gauss at the position of the beam orbit in the ring. This paper describes the design of the septum magnet and the results of the magnetic field measurement. (author)