An IGBT driven slotted beam pipe kicker for SPEAR III injection

Abstract

The SPEAR III injection kicker system is composed of three kicker magnets, K1, K2, and K3. These magnets, along with the power modulators to drive them constitute an injection system which will be used to deflect an incoming electron beam with an energy of 3.3 GeV by an angle of 2.5 mrad for K1 and K3, and 1 mrad for K2. The pulse shape of the magnetic field in the three magnets must be matched in order to preserve a closed orbit. The pulse duration is required to be less than 780 ns, with rise and fall times of less than 375 ns, and a pulse repetition frequency of 10 Hz. The aperture of all three magnets is 60×34 mm in an 8 inch vacuum vessel. The magnetic length is 1.2 m for K1 and K3, and 0.6 m for K2 [1]. The magnet design employs a slotted beam pipe which is shorted at one end. A solid state IGBT based, induction type of modulator drives the magnets. Modulators for K1 and K3 consist of eight 4.5 kV, 600 A IGBTs, and eight Finemet magnet cores with four 22.5 Ohm output cables to drive 2381 A into the magnets. The modulator for K2 uses four IGBTs and cores, and 8 output cables to produce a 2619 A pulse. Cables of length greater than one half the pulse width must be used in order to avoid reflections from the shorted magnet. The design charge voltage for the modulators is 20 kV for K1 and K3. This paper describes the magnet and modulator design, as and presents test data from a prototype system.

IGBT Applications

“…18.19, is the world's longest linear accelerator capable of propelling electrons and positrons to an energy of 50 GeV [22]. The SPEAR III injection kicker system is used to deflect an incoming beam of 3.3 GeV electrons using three kicker magnets K-1, K-2, and K-3 [27]. The deflection angle for the magnets K-1 and K-3 is 2.5 milliradians while that for the K-2 magnet is 1.0 milliradians.…”

Spear 3 Injection Kicker

“…We are considering making the ¿nal strips from stainless steel and copper plating their inside walls. The kicker pulser [3] is a design derived from technology that has been developed by a SLAC/LLNL collaboration for the NLC. The pulser uses individual IGBT assemblies each of which quickly discharges its individual storage capacitor through a transformer into the transmission line load.…”

A slotted beam pipe kicker magnet with solid state drive for SPEAR III

“…It is required that the pulse shape of each kicker he identical in order to have a closed orbit for the injected beam, so the output impedance of K2 must also be half. Therefore, K2 uses a stack of five cores with four cables connected to each of the output terminals.The modulators for KI and K3 are designed to produce bi-polar 20 kV, 3 kA pulses of 1 ps at IO Hz, with rise and fall times of less than 350 11s [2]. Prototypes of both the magnet and the modulator have been built, and components for installation are in fabrication.…”

“…The modulators for KI and K3 are designed to produce bi-polar 20 kV, 3 kA pulses of 1 ps at IO Hz, with rise and fall times of less than 350 11s [2]. Prototypes of both the magnet and the modulator have been built, and components for installation are in fabrication.…”