R. E. Beverly III and Associates - Custom Trigger Generators

Custom Trigger Generators

Introduction

While our standard trigger generator performs well with our smaller trigatron switches, a custom trigger generator is necessary with

Larger field-distortion switches,

Multiple switches operating in parallel, and

Any electrically triggered switch requiring extremely fast, low-jitter operation.

Our standard trigger systems such as the PG-103D generator and OEM trigger modules rely upon a pulse transformer to produce output voltages typically in the 25-40 kV range with rise times measured in the hundreds on nanoseconds. Our custom trigger generators utilize a voltage multiplying, pulse forming line (PFL) to produce considerably faster pulses of higher amplitude. The example shown here is capable of peak voltages up to 120 kV with a rise time of only 3 ns.

Our larger field-distortion switches, such as the SG-184M, require a trigger pulse rise time <10 ns and peak trigger voltage >50 kV. Although our smaller field-distortion switches (e.g., SG-124M) can be fired by transformer based generators, their performance will improve dramatically with a custom trigger generator. With switches operating in parallel, it is usually more cost effective to employ a custom trigger generator when the number of simultaneously operating switches exceeds 4, even with trigatron switches. When laser triggering is not an option, extremely low-jitter operation of any of our switches demands development of a custom trigger source. Multichannel trigger generators have been constructed with as many as 32 channels.

Custom trigger generators are available only when purchasing a complete pulse power system, i.e., switch(es) and trigger generator, and when we have primary responsibility for engineering the system. We do not manufacture these generators as standard products. Proper switch operation demands an integrated approach and therefore we do not sell any custom trigger generator as a stand-alone product.

Representative Custom System

The massively paralleled PG-107 system is designed to fire 24 custom model SG-182 trigatron switches with an intrachannel jitter of <500 ps. The system produces negative 30-120 kV pulses with a fall time of ~3-4 ns. This trigger generator was developed for a major pulsed power installation (240 kJ stored energy, 2.6 MA peak current) at a US national laboratory.

PG-107 generator (24 channels) showing HN-68 output connectors and integral power supply	SG-182 trigatron switch (60 kV, 160 kA, 0.4 coul) with capacitor coupler
PG-107 trigger head assembly and PFL terminator	SG-182 coaxial shield canister with trigger head and HN-88 connectors

Representative unloaded output pulse (12.5 ns/div, 10 kV/div) from the PG-107 trigger generator; measured fall time is limited by probe response (3-4 ns).

Top of page.

References

P. W. Smith, Transient Electronics, Pulsed Circuit Technology (John Wiley and Sons, West Sussix, England, 2002), Ch. 3
F. A. Tuema, S. J. MacGregor and R. A. Fouracre, The design and performance of a low-impedance, self-matched transmission line pulse generator, Measurement Science and Technology 9, 1989 (1998)
I. C. Sommerville, S. J. MacGregor and O. Farish, An efficient stacked-Blumlein HV pulse generator, Measurement Science and Technology 1, 865 (1990)
Specifications for SG-Series Spark-Gap Switches
Application Information for SG-Series Spark-Gap Switches

Inquiries for additional product information are welcome!

Last revision: Wed, 21 Dec 2016 15:04:21 +0000