Improving spatial resolution in X-ray microscopy by using tilted angle detector: A simulation study

TL;DR

This simulation study demonstrates that using tilted angle detectors in X-ray microscopy at 2-5 keV energies can significantly enhance spatial resolution and reduce radiation damage, overcoming limitations of conventional detectors.

Contribution

The paper introduces a simulation-based analysis showing how tilted angle irradiation improves resolution and mitigates damage in X-ray microscopy detectors at specific energies.

Findings

Tilted angle irradiation improves spatial resolution at 2-5 keV energies.

It reduces radiation damage to direct-conversion detectors.

Simulation confirms trade-off between parallax error and resolution enhancement.

Abstract

Conventional x-ray imaging detectors suffer from parallax error when the radiation beam arrives at the detector surface at tilted angle. The image blurring occurs as the radiation penetrates detector material in lateral direction at tilted angle. However, at the photon energies used in x-ray microscopy the attenuation length of the x-rays in the detector material is shorter and consequently the parallax error due to the tilted angle irradiation can be smaller. In these cases, the tilted angle irradiation can be beneficial because it will expand the beam projection ("footprint") at the detector surface, improve spatial resolution and help to overcome inherent resolution limit of the detector. We have performed a simulation study to investigate the above trade-off between the parallax error and improved spatial resolution when tilted angle irradiation is used. Our simulation study showed that tilted angle irradiation at 2-5keV x-ray energies can provide substantial improvements of spatial resolution. We used in our studies the indirect-conversion x-ray microscopy detectors based on scintillators optically coupled to CCD and CMOS cameras, as well as direct-conversion detectors based on back illuminated (back thinned) CCD and CMOS cameras. We have demonstrated also that the tilted angle irradiation can prevent radiation damage of the direct conversion back illuminated CCD and CMOS cameras due to the shallow x-ray attenuation depths with tilted angle geometry.