Linear Transformer Drivers (LTD) for high voltage, high current rep-rated systems

Abstract

The Linear Transformer Driver (LTD) technology can provide very compact devices that deliver very fast high current and high voltage pulses. The output pulse rise time and width can be easily tailored to the specific application needs. Trains of large number of high current pulses can be produced with variable inter-pulse separation from nanoseconds to microseconds. Most importantly these devices can be rep-rated to frequencies only limited by the capacitor specifications that usually is 10Hz. To date we have completed the experimental evaluation of two (LTD I, LTD II) 500-kA cavities in both single and rep-rated modes. A larger 1-MA cavity was tested in a single shot mode and in a voltage adder configuration. The first built inductively isolated 1-MA LTD Voltage Adder (IVA) was composed of five cavity connected in series with a vacuum insulated transmission line. It was tested with both resistive and electron diode loads. The experimental results are in excellent agreement with numerical simulations. Experiments with a 1 TW Inductive Voltage Adder (IVA), which includes ten, 1-MA LTD cavities connected in series, are in preparation at Mykonos LTD Laboratory in Sandia National Laboratories, Albuquerque, NM. This time around the Mykonos voltage adder will be built with a transmission line insulated with de-ionized water. In this experimental work we aim to test the advantages of water insulation as compared to self Magnetic Insulated Transmission Line transport (MITL). It is hoped that the vacuum sheath electron current losses will be avoided without any new difficulties caused by the de-ionized water. This voltage adder will be rep-rated at 6 shots per minute. In the present paper we briefly present the LTD cavity architecture, describe the two LTD cavity types built and experimentally tested in single and rep-rated modes and present the design of the first two-cavity water insulated voltage adder with a liquid salt solution resistive load. This is the first step towards the assembly of a ten-cavity voltage adder of which most of the components are already built and/or fully designed.