• G.C. Pappas
  LBNL, Berkeley, California

For quadrupole or sextupole magnets, the field at the center is zero and will not disturb the stored beam, while the field away from the center increases in magnitude, giving a larger kick to the particles off axis. By pulsing such multipole magnets it is possible to improve the injection efficiency of the Advanced Light Source (ALS) in top off mode. The requirements for a multipole pole kicker injection scheme for ALS are to kick a 1.9 GeV beam by an angle of 10 mrad with a magnet of 1 meter length. Both quadrupole and sextupole magnets have been studied, as well as a dipole magnet with non-constant field magnitude across the center of the aperture. This paper describes the design and gives a comparison of each type of magnet as well as the modulators needed to drive them.

• D. Robin, G.C. Pappas, C. Sun
  LBNL, Berkeley, California
• Z.K. Fisher
  MIT, Cambridge, Massachusetts

We have developed computer models for a pulsed-multipole magnet injection scheme for the Advanced Light Source (ALS) at Lawrence Berkeley National Lab. The multipole kicker injection scheme is further shown to be com- patible with the ALS in combination with a magnet lattice that has a low beta-function in the injection straight. Since traditional injection schemes are not compatible with such optimized low beta lattices, implementing the new injection scheme opens up several new possibilities. For instance, the adoption of a low beta lattice can greatly increase brightness due to the better matching of photon and electron beam emittances. This document explains the principles of the injection and the simulations we performed to show that the concept is sound.

• G.C. Pappas
  LBNL, Berkeley, California

The Next Generation Light Source (NGLS) at Lawrence Berkeley Laboratory is a 2.4 GeV linear accelerator with up to ten FELs. Each of the FELs require a fast kicker, with the exception of the final one which can use a normal bend magnet. The requirements for the kickers are to deflect the linac beam by an angle of 3 mrad with a magnetic length of 2 m, and an aperture size of 17 by 17 mm. A strip line magnet with an impedance of 50 Ohms being feed from the opposite direction as the beam has been selected for prototyping. The modulator requirements to drive such a magnet are ±15 kV and ±300 A, with rise and fall times of 5 ns and a flat top of 10 ns. The pulse to pulse stability must be better than 0.01% of the peak value. The design of the modulator is an inductive adder with 20 cells, each driven by 12 power MOSFETs. This paper describes details of the design as well as present preliminary test data.