Fast X-ray diffraction (XRD) tomography for enhanced identification of materials

Area of Science:

• Medical Imaging and Security Technology
• Materials Science and Spectroscopy

Background:

• X-ray computed tomography (CT) offers density and effective atomic number data but struggles to differentiate certain threats from benign materials.
• X-ray diffraction (XRD) provides superior material-specific identification but suffers from weaker diffracted photon flux, leading to longer scan times.
• Current limitations in distinguishing threats necessitate advanced imaging solutions for security applications.

Purpose of the Study:

• To numerically analyze a novel low-cost scanner design capable of simultaneously capturing CT and XRD signals.
• To develop and validate a forward model simulating a realistic instrument, accounting for polychromatic spectra, detector, and geometric factors.
• To demonstrate the feasibility of reconstructing XRD patterns from noisy data and assess its contribution to threat detection.

Main Methods:

• A numerical analysis of a novel scanner design with minimized collimation to maximize photon flux for simultaneous CT and XRD data acquisition.
• Development of a forward model incorporating polychromatic spectrum, detector, and finite-size geometric effects for realistic instrument simulation.
• Reconstruction of XRD patterns from simulated data, including Poisson noise and incoherent scattering, using GPU-accelerated software.

Main Results:

• The proposed scanner design successfully captures both CT and XRD signals simultaneously.
• Reconstructed XRD patterns provide low-resolution, material-specific information that complements CT images.
• The integrated approach shows potential for enhanced threat detection by adding valuable material identification capabilities.

Conclusions:

• Simultaneous CT and XRD scanning offers a promising approach to improve threat detection in security applications.
• The developed numerical model and reconstruction techniques are crucial for optimizing such dual-modality scanner designs.
• This technology has potential applications beyond security, including healthcare and manufacturing quality control.