Triple-pulse X-ray spot size measurement of the Dragon-II linear induction accelerator

TL;DR

This paper measures the X-ray spot size of the Dragon-II linear induction accelerator's triple-pulse electron beams using pinhole imaging, analyzing spatial distribution and asymmetry to evaluate image quality.

Contribution

It introduces a method to accurately measure and analyze the spatial distribution and asymmetry of triple-pulse X-ray sources in the Dragon-II accelerator.

Findings

Measured spot sizes for each pulse using FWHM and LANL definitions

Analyzed azimuthal asymmetry of the X-ray source

Calculated weighted RMS radius considering photon contributions

Abstract

The Dragon-II linear induction accelerator is able to provide triple-pulse electron beams with an adjustable pulse spacing at the minimum of 300 ns. As a main determinant of the image quality, the X-ray spot size is usually quoted as an evaluation of the resolving power. The pinhole imaging method is applied to measure the two-dimensional spatial distribution of the triple-pulse X-ray source, by which the azimuthal asymmetry of the source can be analyzed. The spot size of each pulse is characterized by both the full-width at half-maximum and the LANL definition. The weighted RMS radius at different sum ratios of photon intensity is also calculated, which directly takes into account the contribution of every single photon within the boundary of the spot.