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XX International Linac Conference

TUB01 (Poster)

Presenter: James Fockler (LBNL)
Status: Incomplete - No full text

A Precise, 3.2 MV 2.0 ms, Marxed PFN for Radiography*

J. Fockler, D. Anderson, C. Eichenberger, P. Corcoran, S. Eylon, H. Lackner, D. Pellinen, R. Wells, S. Yu (LBNL),

This paper describes the design and performance of a Marxed PFN for the 3.2 MV, 2.0 kA electron beam injector of the 2nd axis of the Dual Hydrodynamic Radiography Test, DARHT, facility at LANL. The beam requirement calls for a square voltage waveform of 2ms flat to 0 1 0.5%. The Marx generator consists of 88 stages arranged in a two-column low inductance configuration, which minimizes erection delay. The stages are charged to a nominal 1 41.6 kV (1 50 kV max.). Each half stage consists of an critically damped Gibbs section that pulse charges 1.0 nF of stray capacitance of the Marx, insulator stack and diode, with a 10-90% ristime of 300 ns, and 5 PFN sections that generate the 2.1ms (99-99%) square wave. The erected PFN impedance is 675 ohms and a series resistance of 82 ohms is used to limit capacitor reversal and spark gap charge transfer in shorted load faults. It operates reliably at 5 shots per minute, < 1 prefire in 1000 shots, and erection jitter < 10 ns (1s).
*Work supported by the US Department of Energy under contract DE-AC03-76SF00098

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