Magnet

A special interleaving operation of the Advanced Photon Source’s injector requires three dipole magnets to selectively direct linac beam bunches into the storage ring during “top-up ” operation. A versatile switching mode power supply has been designed and built for the magnets to meet that requirement. This paper presents the main circuit, the circuit analysis, and the test results. 1 REQUIREMENT The APS storage ring requires a beam injection about every two minutes in top-up mode [1]. The so-called interleaving operation allows beam pulses between injections to be used for machine studies. It also allows more sophisticated diagnostic techniques than otherwise would be possible. Three pulsed dipole magnets are required to interleave the storage ring top-up injection and noninjection studies. The beam is delivered for the storage ring injection when these magnets are energized and is available for studies when the magnets are off. One mode of operation is to run the injector at up to 10 Hz, while only injecting into the booster at 2 Hz. In order to do so, the dipole magnet current has to rise or fall within 100 ms and the pulse has to complete within 200 ms. There are also times when the continuous booster injection is required. Then those magnets will be running in DC mode. The switch between modes needs to be smooth and fast. Table 1.1 is a summary of the specifications