Spot size measurement of flash-radiography source utilizing the pinhole imaging method

TL;DR

This paper presents a method using pinhole imaging to accurately measure the x-ray source spot size in a flash-radiography facility, providing detailed spatial distribution data crucial for resolving power evaluation.

Contribution

The study applies the pinhole imaging technique to measure and analyze the source spot size of a linear induction accelerator, including the spatial distribution and modulation transfer function.

Findings

Measured spot size using FWHM and MTF methods

Obtained two-dimensional spatial distribution of the source

Analyzed effects of electron beam focusing adjustments

Abstract

The spot size of the x-ray source is a key parameter of a flash-radiography facility, which is usually quoted as an evaluation of the resolving power. The pinhole imaging technique is applied to measure the spot size of the Dragon-I linear induction accelerator, by which a two-dimensional spatial distribution of the source spot is obtained. Experimental measurements are performed to measure the spot image when the transportation and focusing of the electron beam is tuned by adjusting the currents of solenoids in the downstream section. The spot size of full-width at half maximum and that defined from the spatial frequency at half peak value of the modulation transfer function are calculated and discussed.