Design and test results of kicker units for the positron accumulator ring at the APS
Three fast kicker units have been designed, tested, and installed in the positron accumulator ring (PAR) at the Advanced Photon Source (APS) for beam injection and extraction. The performance of these kicker units has been satisfactory. This paper presents the design and test results.
Kicker Systems
Each stage of an accelerator system has a limited dynamic range and therefore a chain of stages is required to reach high energy. A combination of septa and kicker magnets is frequently used to inject and extract beams from each stage. The kicker magnets typically produce rectangular field pulses with fast rise and/or fall times; however, the field strength is relatively low. To compensate for their relatively low field strength, the kicker magnets are generally combined with electromagnetic septa. The septa provide relatively strong field strength but are either DC or slow pulsed. This paper discusses injection and extraction systems with particular emphasis on the hardware required for the kicker system. Design options and computer aided design tools are also discussed. In addition, the interaction of the beam with the kicker system, primarily the kicker magnet, is considered.
Life extension of thyratrons in short pulse circuits with the use of saturable magnetic sharpeners
Recent developments in dispenser cathode thyratrons have shifted the dominant life-limiting factor to the anode in high di/dt short-pulse circuits. Calculations and measurements indicate that the addition of a magnetic switch should reduce the anode temperature and the erosion rate. The addition of a saturating magnetic switch has several advantages. First, by reducing the amount of anode dissipation during the commutation phase of the thyratron, it reduces cooling requirements. Second, it reduces the switching time in a thyratron limited circuit; and third, it can decrease the amount of anode damage due to high-energy electrons associated with the commutation phase or anode fall. The saturating magnetic switch allows the anode voltage to collapse while delaying the forward current, thus reducing the electron energy to a level below that which results in erosion.<<ETX>>