In-situ magnetic gauging technique used at LANL-method and shock information obtained

Abstract

Measuring techniques, including magnetic gauges, quartz gauges, manganin gauges, PVDF gauges, velocity interferometry, piezoelectric pins, shorting pins, flash gaps, etc., have been used over the years in shock experiments in condensed phase materials. The use of a particular technique depends on the measured parameter and the sample material properties. This paper concentrates on in-situ magnetic gauging which is particularly useful in high explosive (HE) shock initiation experiments. A short history of this technique will be given but the main discussion will concentrate on the multiple magnetic gauge technique developed at Los Alamos National Lab. (LANL). Vorthman and Wackerle started the technique development in 1980, concentrating on particle velocity and “impulse” gauges so that Lagrange analysis could be used to map the entire reactive field. Over the years, changes to the gauge design, fabrication, and experimental focus have led to the present LANL technique. During the past two years measurements have tracked the reactive wave evolution resulting from a shock-to-detonation transition in several high explosive materials. Analysis of the data from a single experiment provides: 1) an unreacted Hugoniot point in which both the shock velocity and particle velocity are measured, 2) shock front tracking, 3) ten particle velocity profiles which measure the reactive wave evolution, 4) a “Pop-plot” distance-(time-)to-detonation point, and 5) a 3% measurement of the detonation velocity. Details of the experimental setup and information from several experiments will be discussed.