DARHT Axis 1 Compensation Can D-dot Calibration

TL;DR

This paper presents a detailed calibration procedure for D-dot probes used in high-voltage measurements at LANL's DARHT Axis 1, including simulation, setup, and results, serving as a guide for similar calibrations.

Contribution

It provides a comprehensive calibration method for D-dot probes in high-voltage environments, including simulation and practical setup details, which is novel for this application.

Findings

Calibration achieved with high accuracy using low-voltage pulses

Simulation results support calibration methodology

Guidelines established for similar high-voltage probe calibrations

Abstract

We detail the calibration of the D-dot probes used on the Los Alamos National Laboratory DARHT Axis 1 LIA compensation cans (CCs). We hope this will serve not only as a record of this calibration, but also as a guide on how to perform similar calibrations on other systems where D-dots are deployed. Although a simple measurement, its difficulty lies in the fact that the same geometry used when fielded must be used during calibration, the ultimate goal being to measure the capacitance between the probe sensor and the component whose voltage one intends to measure. Because of its linearity with voltage, this can be done at a lower voltage than during fielding, the only caveat being that this lower voltage pulse must still provide enough signal to noise. After a brief summary of our results, we include a description of a compensation can, the D-dot probe and its operation. We then provide 3D simulation results of the capacitance of this probe to the high voltage bushing under test inside of the compensation can. Finally, we describe our calibration setup and discuss our results.