Non-destructive evaluation of artillery combustible cartridge case using terahertz radiation

Abstract

In this study, terahertz radiation was employed to determine the radius, diameter, and thickness of the nitrocellulose combustible cartridge case used for tank ammunition. The construction of the sample was outlined, and the refractive index of the case material was measured. A terahertz rotary scanner with a time-domain spectroscopy setup in reflection configuration was developed, and its performance and parameters were determined. A wire polariser was introduced as a reference to determine the stable time difference. The radius and diameter measurements of the case were based on a reference terahertz pulse reflected from its metal base. The thickness of the case was calculated based on the time difference between pulses reflected from its inner and outer surfaces. These measurements were in agreement with the reference measurements. The results prove that the developed setup and measurement methods are suitable for the non-destructive evaluation of cases and provided satisfactory performance.