Experiments on bright field and dark field high energy electron imaging with thick target material

TL;DR

This paper demonstrates high-resolution electron radiography using bright and dark field imaging techniques with 45 MeV electrons, achieving micrometer spatial resolution and enhanced detail detection in thick, high-density targets.

Contribution

It introduces a novel application of bright and dark field electron imaging for high energy density physics, achieving micrometer resolution in thick targets.

Findings

Achieved ~4 micrometer spatial resolution.

Successfully imaged 300-600 micron thick silicon targets.

Dark field imaging revealed additional boundary and defect details.

Abstract

Using a high energy electron beam for the imaging of high density matter with both high spatial-temporal and areal density resolution under extreme states of temperature and pressure is one of the critical challenges in high energy density physics . When a charged particle beam passes through an opaque target, the beam will be scattered with a distribution that depends on the thickness of the material. By collecting the scattered beam either near or off axis, so-called bright field or dark field images can be obtained. Here we report on an electron radiography experiment using 45 MeV electrons from an S-band photo-injector, where scattered electrons, after interacting with a sample, are collected and imaged by a quadrupole imaging system. We achieved a few micrometers (about 4 micrometers) spatial resolution and about 10 micrometers thickness resolution for a silicon target of 300-600 micron thickness. With addition of dark field images that are captured by selecting electrons with large scattering angle, we show that more useful information in determining external details such as outlines, boundaries and defects can be obtained.