Magnetic pulsed septa for the synchrotron “Pakhra”

Slow extraction system of the Synchrotron “Pakhra” contains two pulsed septum magnets. They are located inside the synchrotron vacuum chamber. Both the soft and the hard septum magnets have similar mechanical construction. They consist of four magnetic blocks split by three copper brackets. The dimensions of the magnetic gap are 1.2 cm height and 3.6 cm width. The soft septum thickness is 0.1 cm. The septum is cooled indirectly by the copper brackets. The fringing field is less than 2% of the field in the core gap. To generate the maximum field of 0.08 T in an one-turn winding 800 A current is required. The second septum is water cooled and it is 0.5 cm thick. The field strength of this magnet can be raised up to 0.4 T at 4000 A. The septa are fed by current pulsers. The leading edge of the pulses is 1 msec and their flat peaks range from 2 msec to 3 msec. Repetition rate is 50 Hz