A high-speed, eight-wavelength visible light-infrared pyrometer for shock physics experiments

Rongbo Wang,Shengfu Li,Jianhua Tian,Xianchao Cheng,Weijun Zhou,Zhen-Xiong Luo,Jianhua Meng,Lihua He

doi:10.1063/1.4996927

Abstract

An eight-channel, high speed pyrometer for precise temperature measurement is designed and realized in this work. The addition of longer-wavelength channels sensitive at lower temperatures highly expands the measured temperature range, which covers the temperature of interest in shock physics from 1500K-10000K. The working wavelength range is 400-1700nm from visible light to near-infrared (NIR). Semiconductor detectors of Si and InGaAs are used as photoelectric devices, whose bandwidths are 50MHz and 150MHz respectively. Benefitting from the high responsivity and high speed of detectors, the time resolution of the pyrometer can be smaller than 10ns. By combining the high-transmittance beam-splitters and narrow-bandwidth filters, the peak spectrum transmissivity of each channel can be higher than 60%. The gray-body temperatures of NaI crystal under shock-loading are successfully measured by this pyrometer.

Highlights

A reliable temperature measurement is a key diagnostic in many industrial and scientific applications.[1,2,3,4,5,6,7,8,9,10] Of special interest is the temperature measurement of a sample under shock loading
The radiation from the target in the field of view (FOV) of the system is collected by the optical probe
It passes through the fiber (F1), and is coupled and collimated by the fiber coupler (FC) and the broadband collimating lens (LL)

Summary

INTRODUCTION

A reliable temperature measurement is a key diagnostic in many industrial and scientific applications.[1,2,3,4,5,6,7,8,9,10] Of special interest is the temperature measurement of a sample under shock loading. Temperature measurement is one of the grand challenges still facing experimental shock physics. The wavelength range of peak blackbody spectral radiance for these temperatures where signal would be maximum is from 280 nm to 1930 nm calculated by the Wien’s displacement law λmax=2897.7 (μm K)/T.13. As limited by the currently applicable detectors, we have developed an eightchannel, high-speed, single-fiber instrument in the spectral range of 400nm thru 1700nm in this work. The semiconductor detectors of Si and InGaAs are used as photoelectric devices, whose bandwidths are 50 MHz and 150 MHz respectively. The temperatures of NaI crystal under shock-load are successfully measured by this pyrometer

System structure

Working wavelength and detector of each channel

Splitting coupler module

EXPERIMENTAL IMPLEMENTATION

Findings

CONCLUSIONS