Micro-Computed Tomography beamline (MCT)

Capability summary and techniques

The MCT beamline complements the existing X-ray imaging and tomography capabilities provided by the Imaging and Medical Beamline (IMBL), and targets applications requiring higher (sub-micron) spatial resolution and involving smaller samples.  MCT is a bending-magnet beamline, operating with X-rays in the energy range of 8 to 40 keV.  Monochromatic X-rays is selected using a double-multilayer monochromator (DMM).  The DMM operates with a relatively wide energy bandpass (ΔE/E~3%) in order to increase the integrated flux at the sample position. The DMM can also be removed from the X-ray beam path, enabling experiments with a high flux, filtered white beam, for studies that require high-speed data acquisition. The photon-delivery system (PDS) has a single-(vertical) bounce mirror (VBM), capable of suppressing harmonic contamination in low-energy monochromatic beams and providing the means to shape the spectrum of filtered white beams on the high-energy side. The beamline is greatly benefit from novel phase-contrast modalities (such as propagation-based, grating-based and speckle) in addition to conventional absorption-contrast computed tomography. The beamline will be equipped with a robotic stage for high-throughput automated sample exchange.  A higher-resolution (nano-CT) configuration based on the use of a Fresnel zone plate system will also be available.

The wide variety of experimental configurations, designed in response to the requirements of a diverse user community can be achieved using three different X-ray imaging detector systems.  These will address key issues such as spatial resolution, contrast, field-of-view, frame rate and white-beam compatibility.

In addition to standard “step-and-shoot” and “on-the-fly” modalities for absorption- and phase-contrast X-ray tomography, MCT will provide capabilities for tomosynthesis, laminography, and helical scanning.  It is envisaged that absorption-contrast and propagation-based phase-contrast imaging will be “workhorse” techniques, however the other phase-contrast modalities will be made available for more specialist requirements, such as dark-field imaging.  Rapid two-dimensional imaging of dynamic processes will also be possible, including via various forms of triggering.

Streamlined data collection, processing, reconstruction, segmentation, rendering and analysis protocols and pipelines will be available via innovative software (including specialised algorithms such as for phase retrieval) and high-performance computing infrastructure.