The Booster to AGS Beam Transfer Fast Kicker Systems

The Brookhaven AGS Booster had a very successful commissioning period in June 1991. The third phase of that commissioning was a beam extraction test. The Booster extraction fast kicker (F3) deflected a 1.2 Gev proton beam from the Booster circulating orbit into the extraction septum aperture, partially down the.extraction line to a temporary beam stop. Now, the Booster is committed to the AGS operations program for both heavy ion and proton beams. Thus, the Booster extraction and the corresponding AGS injection systems must operate routinely up to a pulse repetition frequency of 7.5 Hertz, and up to a beam energy of 1.5 Gev. The injection fast kicker is located in the A5 section of the AGS ring and is used to deflect the proton or heavy ion beam into its final AGS closed orbit. The Booster extraction and the AGS injection fast kickers are both multi-module systems. Also, they both serve the dual-function of deflecting the proton or heavy ion beams, which require a change in pulse rise time, amplitude, flat top duration, and the fall time. For each system, the multiple modules are arranged electrically in parallel. Each module drives one lumped inductance picture frame magnet section, and the magnets are arranged mechanically in series. The pulsed current delivered from the modulator creates a pulsed magnetic field in the magnet aperture which imparts an angular deflection to the passing particle beam from/into the machine orbit. A distinctive feature of the AGS injection fast kicker modulators is the tail-bitting function required for proton beam injection. This enables the system to produce a fast current fall time (<140 ns) to go along with the high current pulse amplitude 1100 Ampere/module) modulator consists of two thyratrons. The main PFN thyratrons switch on the current, and the tail bitting thyratrons are used to force the magnet current to decrease rapidly. Two digital pulse delay generators are used to align the main thyratrons and the tail bitting thyratrons respectively. The system has been tested and installed. The final commissioning of the Booster to AGS beam transfer line and injection is currently being undertaken. In this article, the system design, realization techniques and performance data will be presented.