The XFM beamline at the Australian Synchrotron

Abstract

The X-ray fluorescence microscopy (XFM) beamline is an in-vacuum undulator-based X-ray fluorescence (XRF) microprobe beamline at the 3 GeV Australian Synchrotron. The beamline delivers hard X-rays in the 4–27 keV energy range, permitting K emission to Cd and L and M emission for all other heavier elements. With a practical low-energy detection cut-off of approximately 1.5 keV, low-Z detection is constrained to Si, with Al detectable under favourable circumstances. The beamline has two scanning stations: a Kirkpatrick–Baez mirror microprobe, which produces a focal spot of 2 µm × 2 µm FWHM, and a large-area scanning `milliprobe', which has the beam size defined by slits. Energy-dispersive detector systems include the Maia 384, Vortex-EM and Vortex-ME3 for XRF measurement, and the EIGER2 X 1 Mpixel array detector for scanning X-ray diffraction microscopy measurements. The beamline uses event-mode data acquisition that eliminates detector system time overheads, and motion control overheads are significantly reduced through the application of an efficient raster scanning algorithm. The minimal overheads, in conjunction with short dwell times per pixel, have allowed XFM to establish techniques such as full spectroscopic XANES fluorescence imaging, XRF tomography, fly scanning ptychography and high-definition XRF imaging over large areas. XFM provides diverse analysis capabilities in the fields of medicine, biology, geology, materials science and cultural heritage. This paper discusses the beamline status, scientific showcases and future upgrades.

An in situ, micro-scale investigation of inorganically and organically driven rare-earth remobilisation during weathering

“…Polished thin sections of both samples (~70 × 25 mm at 30 μm thickness) were made using quartz glass (Ted Pella, Inc, Redding, California). These thin sections were mapped using microXRF (beamsize ~2 μm) and the Maia 384 detector at the XFM beamline of the Australian Synchrotron (Victoria, Melbourne, Clayton; Howard et al , 2020). Overview maps of each sample were made at 18.5 kV, 4 μm pixel size, 0.22 ms per pixel dwell time and a velocity of 18 mm/s.…”

The transfer and persistence of metals in latent fingermarks

“…The XFM beamline at the Australian synchrotron 45 was used for elemental analysis of fingermark samples following previous studies published by Boseley et al, 31 and following the method published by Summers et al 46 In brief, a monochromatic micro-X-ray beam (15.8 keV, 2 µm spot size at 2 sigma) was focussed using a Kirkpatrick-Baez mirror pair. Data was collected in back-scatter geometry, with the sample mounted normal to incident X-ray source.…”

NanoMAX: the hard X-ray nanoprobe beamline at the MAX IV Laboratory

“…The sensitivity to angular errors in optical components is lower in the horizontal direction because the photon source in the undu- lator is strongly elliptical in shape (see Table 1). Horizontally deflecting optics is the chosen design for several hard X-ray nanoprobe beamlines (Chang et al, 2013;Howard et al, 2020;Leake et al, 2019;Li et al, 2017;Quinn et al, 2021;Somogyi et al, 2015) at third-and fourth-generation sources.…”