Spectroradiometry with sub-microsecond time resolution using multianode photomultiplier tube assemblies

Abstract

Accurate and precise measurements of spectroradiometric temperature are crucial for many high pressure experiments that use diamond anvil cells or shock waves. In experiments with sub-millisecond timescales, specialized detectors such as streak cameras or photomultiplier tubes are required to measure temperature. High accuracy and precision are difficult to attain, especially at temperatures below 3000 K. Here we present a new spectroradiometry system based on multianode photomultiplier tube technology and passive readout circuitry that yields a 0.24 $\mu$s rise-time for each channel. Temperature is measured using five color spectroradiometry. During high pressure pulsed Joule heating experiments in a diamond anvil cell, we document measurement precision to be $\pm 30$ K at temperatures as low as 2000 K during single-shot heating experiments with $0.6$ $\mu$s time-resolution. Ambient pressure melting tests using pulsed Joule heating indicate that the accuracy is $\pm 80$ K in the temperature range 1800-2700 K.