Seminars Archive

Fast fluorescence tomography at the Australian Synchrotron: present and future.

Abstract
Scanning x-ray fluorescence microscopy (XFM) has traditionally been regarded as a slow technique, due to instrumental limitations and the perceived limitations of scanning measurements. The Maia detector system - developed through a collaboration between the CSIRO (Aust), BNL (USA), and the Australian Synchrotron - has enabled pixel rates of up to 20 kHz, at high statistical level due to increases in detector solid angle and thus overall experimental efficiency. In addition, detector pixellation adds an additional dimension to our data that we are beginning to investigate. We have used these performance features to bring high-definition fluorescence tomography into the present, with several examples of reconstructions with up to around 100 Mvoxels. We have explored a number of unique fluorescence tomographic modalities such as: high definition single slice tomography, XANES tomography, and cryo-tomography, and are undertaking several hardware upgrades so as to bring these into routine service. Significant challenges of high pixel rate include a pressing need to develop quality correction algorithms for self-absorption effects. Here we discuss several of the challenges and the opportunities facing fast fluorescence tomography, with some view of the fundamental limitations of the technique.