• T.G. Beukers, J.W. Krzaszczak, M.H. Larrus, A.C. de Lira
  SLAC, Menlo Park, California

Funding: Work supported by the Department of Energy under contract No. DE-AC02-76SF00515.

The design and installation of the Linac Coherent Light Source* at SLAC National Accelerator Laboratory has included the development of a kicker system for selective beam bunch dumping. The kicker is based on an LC resonant topology formed by the 50 uF energy storage capacitor and the 64 uH air core magnet load and has a sinusoidal pulse period of 400us. The maximum magnet current is 500 A. The circuit is weakly damped, allowing most of the magnet energy to be recovered in the energy storage capacitor. The kicker runs at a repetition rate of 120Hz. A PLC-based control system provides remote control and monitoring of the kicker via EPICS protocol. Fast timing and interlock signals are converted by discrete peak-detect and sample-hold circuits into DC signals that can be processed by the PLC. The design and experimental characterization of the systems is presented.

*http://ssrl.slac.stanford.edu/lcls/

• C. Burkhart, T.G. Beukers, M.A. Kemp, R.S. Larsen, K.J.P. Macken, M.N. Nguyen, J.J. Olsen, T. Tang
  SLAC, Menlo Park, California

Funding: Work supported by the U.S. Department of Energy under contract DE-AC02-76SF00515

A program is underway at SLAC to develop a Marx-topology klystron modulator for the International Linear Collider* project. It is envisioned as a smaller, lower cost, and higher reliability alternative to the bouncer-topology baseline design. The application requires 120 kV (±0.5%), 140 A, 1.6 ms pulses at a rate of 5 Hz. The Marx constructs the high voltage pulse without an output transformer, large at these parameters, by instead combining a number of lower voltage cells in series. The modularity of the Marx topology is further exploited to achieve a redundant, high-availability design. The ILC Marx employs solid state elements; IGBTs and diodes, to control the charge, discharge and isolation of the cells. The SLAC designs are oil-free; air is used for high voltage insulation and cooling. The first generation prototype, P1, is undergoing life testing. Development of a second generation prototype, P2, is underway. Status updates for both prototypes will be presented.

*ILC Reference Design Report, http://www.linearcollider.org/cms/?pid=1000437

• K.J.P. Macken, T.G. Beukers, C. Burkhart, M.A. Kemp, M.N. Nguyen, T. Tang
  SLAC, Menlo Park, California

Funding: Work supported by the U.S. Department of Energy under contract DE-AC02-76SF00515

Introduced by the U.S. Navy more than a decade ago*, the concept of Power Electronic Building Blocks (PEBBs) has been successfully applied in various applications. It is well accepted within the power electronics arena that this concept offers the potential to achieve increased levels of modularity and compactness. This approach is thus ideally suited for applications where easy serviceability and high availability are key, such as the ILC. This paper presents a building block approach for designing Marx modulators. First the concept of "bricks and buses" is briefly discussed. Then a PEBB-oriented design is presented for the basic Marx cell of a 32-cell Marx modulator to power an ILC klystron; 120 kV, 140 A, 1.6 ms pulses at a repetition rate of 5 Hz. Each basic Marx cell is composed of a main cell and a correction cell that compensates the main cell droop. The main cell has a stored energy of 2.1 kJ per Marx cell and the correction cell an additional 0.5 kJ. This design allows over 30% of the total stored energy in the Marx modulator, 84 kJ, to be delivered in the output pulse, 26.9 kJ, while keeping the droop within a ±0.5% range.

*T. Ericsen. 'Power Electronics Building Blocks - A systematic approach to power electronics.' In: Proceedings of Power Engineering Society Summer Meeting, Seattle, WA, 16-20 July 2000.