The author consider here a novel trigger for high-voltage spark-gap switches that uses a ferroelectric material as an electron source. The new device is called a ferratron because it is in some ways reminiscent of a trigatron, and because it uses a ferroelectric material to inject electrons into the gap to trigger the breakdown. The device presently under advanced development uses a ferroelectric ceramic as the electron source, coupled with a high gas flow rate. This configuration allows reliable triggering at low trigger voltages, even at high repetition rates. The trigger system is integrated into a switch chamber design capable of sustaining 500 kV at a pressure of 1500 psig, The switch chamber is tailored to reduce field stresses and to provide a low inductance current path with a very compact geometry. The high gas flow rate allows the replacement of the gas in the discharge region within the time scale necessary to sustain a repetition rate of 100 Hz to 1 kHz. The switch has been successfully operated during preliminary tests using N/sub 2/ at low pressures with a transmitted risetime of 500 ps. The jitter was found to be less than 70 ps at a rep rate of 1 Hz. Faster risetimes, along with higher repetition rates and higher voltages, will be attained as development progresses.
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