A Low Jitter, Hydrogen Thyratron Pockels Cell Driver
Abstract:
The requirements to be met by Pockels cell drivers for incorporation into the Novette and Nova Laser systems are presented, and critical aspects of the specification examined. A high performance pulse generator has been developed to meet these requirements using new thyratron technology from the English Electric Valve Co. Ltd. Two closely related versions have been built a 10KV output unit with 9 nsec risetime into five parallel 50 ohm loads and a faster 5KV output driver with 3.5 nsec risetime into a single 50 ohm load. The design approach for optimizing performance, using the new tubes in relation to the LLNL specification is described, including the techniques used for control of electromagnetic interference. Only power and a fiber optic trigger are required for operation of the generators. Output pulse width can be changed in a few minutes using interchangeable internal charge line sets. Circuitry is all solid-state except for the output switch, which is expected to have the excellent life and reliability of modern hydrogen filled thyratrons. Jitter of less than 0.2 nsec and continuous operation up to 10 Hz rep rate has been achieved. Performance in the laser systems environment, including noise immunity, has been demonstrated and the Novette and Nova laser systems will ultimately employ several of these units.