BST is an electron synchrotron which accelerates the electrons injected from the injector linac up to 1.3 GeV in maximum. The required energy to accelerate and store the electron beam is supplied by a 500 MHz rf cavity. By inserting a very fine carbon wire to the beam orbit of circulating electrons after the acceleration, high energy gamma rays are generated via bremsstrahlung. Two beam lines are operational to utilize such gamma rays. In a typical operation pattern, beam acceleration is immediately started just after the injection and finished within ~2 sec., and then stored electrons with ring current of 10~30 mA are consumed to generate the gamma rays over a duration of about 10~40 sec. Currently available operation energy is 1.3, 1.0 and 0.8 GeV, and typical ring current is ~10～30 mA.
BST ring. The ring circumference is 50 m, and eight dipole magnets (blue pieces) deflect the electrons so as to guide the electron beam, while the focusing magnets (orange and red magnets) are used to keep the electrons circulating inside the vacuum chamber.
Combined function magnet. It looks like an ordinary quadrupole magnet but has a special pole-face shape to generate the sextupole component, and thus the chromaticity correction can be accomplished with these magnets by introducing the dispersion function to the magnet location.
| Injection Beam Energy | Injection Repetition | Ring Top Energy | Storage Beam Current |
|---|---|---|---|
| 90 MeV | ~0.05 Hz (typ.) | 0.8~1.3 GeV | ~30 mA |
