We would like to announce the next Imaging and Optical Physics Seminar, which will be held on-line via Zoom (see connection details below) from 12 pm on Tuesday, 1 December, 2020 (note the slightly different time compared to the previous seminars). The presenters will be Dr Daniel Hausermann (Australian Synchrotron, ANSTO) and Dr Amelia Liu (Monash University). You can find abstracts for the presentations below.
Here are the connection details for this webinar:
Join from a PC, Mac, iPad, iPhone or Android device:
Please click this URL to start or join. https://monash.zoom.us/j/85474127305?pwd=S1p5ZTVwa3hXcFhSaE1tV1hTRDhudz09
Dr Amelia Liu (Monash University)
Title: Topological predictors of structural instability in glasses.
Abstract: Large area diffraction patterns of glasses are composed of diffuse, isotropic rings that arise from the large variety of local structures that exist in the disordered material. If the diffracting volume is limited to the correlation length, this isotropic diffracted intensity breaks up into discrete regions or “speckle”. The angular symmetries in such “speckle” patterns reflect the local symmetries in the glass’ structure from within the probed volume. Using scanning micro-SAXS we mapped the local symmetries in a colloidal glass and compared these to the local time correlation coefficient obtained from successive spatial scans. We found that low-symmetry local structures were linked to structural instability. Examining the structural transformations after the application of a compressive force, these same low-symmetry local structures were associated with shear instabilities, and the localization of strain in a shear “band”. The shear band involved co-operative transformations of local structures over length scales hundreds of times the size of the particle. This experiment makes a firm connection between local symmetry and the larger scale co-operative structural transformations that govern deformation in glasses.
Dr Daniel Hausermann (Australian Synchrotron - ANSTO)
Title: Addressing the challenges of live human CT on a synchrotron radiation source
Abstract: ANSTO’s Imaging and Medical Beamline accepts 23 kW of X-rays into its ‘front end’. And yet it can safely scan a human patient to obtain a high contrast, 3D breast image, with a mean glandular dose of 2 mGy. And this without having to spin the synchrotron and a detector around the subject.This presentation will cover the challenges of turning a potentially lethal weapon into a safe, game-changing, medical imaging instrument.