Development of Solid-State Drivers for the NIF Plasma Electrode Pockels Cell

Abstract

Large aperture Plasma Electrode Pockels Cells (PEPC) are an enabling technology in the National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory. The Pockels cell allows the NIF laser to take advantage of multipass amplifier architecture, thus reducing costs and physical size of the facility. Each Pockels cell comprises four 40-cm x 40-cm apertures arranged in a 4x1 array. The combination of the Pockels cell and a thin-film polarizer, configured in a 4x1 array, form an optical switch that is key to achieving multi-pass operation. Solid-state Plasma Pulse Generators (PPGs) and high current high voltage solid-state Switch Pulse Generators (SPGs) have been developed for use in the PEPC. The solid-state plasma pulse generators initiate and maintain plasma within the cells; each pulser is capable of delivering 60J of energy to each plasma channel. Deployment of the solid-state PPGs has been completed in NIF. The MOSFET-switched SPG is capable of delivering a requisite fast rise time, 17kV flattop pulse to the cells' nonlinear crystals.A complete software and hardware control system has been developed and is currently being tested for use on the solidstate SPGs. Also a transmission line modeling, development, and testing effort is in process, in support of NIFs' Advanced Radiographic Capabilities (ARC). Work is scheduled for completion by the end of the calendar year.

Pjezoelektrinių virpesių slopinimo pokelso narveliuose tyrimas

“…Various topologies of high voltage pulse generators (Pockels cell drivers) have been used for the control of the Pockels cells: high frequency triodes (Bado et al 1998), krytrons (Hyer et al 2008;Hyde et al 1977), thyratrons (Barbosa et al 2007;Barbosa et al 2008), discharge (Essmann et al 2018;Kimura 2017) and drift-step-recovery diodes (Kesar et al 2016). Each of the topologies has its advantages and disadvantages (Jiang et al 2004), but the most common are two: MOSFET and avalanche bipolar transistors.…”

Prototype Inductive Adders With Extremely Flat-Top Output Pulses for the Compact Linear Collider at CERN

“…Livermore National Laboratory in [6], with examples of using modulation techniques for adjusting output waveforms. More recent research on inductive adders, also called inductive voltage adders or linear transformer drivers in the literature, have been carried out for Pockels cells divers for the National Ignition Facility [7], fast kicker systems at the Lawrence Berkeley National Laboratory [7], and industrial applications of pulsed power [9]. With a careful design of the inductive adder, it may be possible to directly meet the ripple and droop requirements of the PDR kicker and analog modulation may provide a means to meet the demanding specifications for the DR extraction kicker [10], [11].…”