Around the instruments
Quokka (SANS)
The first experiment as part of the peer-reviewed user programme on Quokka was completed in March by the group of Professor Tsang-Lang Lin from the National Tsing-Hua University in Taiwan. Their experiment investigating multi-lamellar lipid-DNA complexes was evidently successful as can be seen below:
Instrument scientist Elliot Gilbert with I-Ting Liu, Po-Wei Yang and Tsang-Lang Lin from the National Tsing-Hua University
We have also recently successfully commissioned the first stage of focussing optics. Quokka is now able to reach a minimum q of about 0.0006 Å-1 using a wavelength of 8.9 Å by focussing the neutron beam on the detector at a distance of 20.9 m from the sample using an array of 24 MgF2 lenses. This minimum q is below the design requirement of 0.0008 Å-1 and additional experiments are planned to reduce this further.
Data collected from a latex sample in D2O using the Quokka focussing optics
In other news, the first deuterated protein produced by the National Deuteration Facility has also been investigated on Quokka while Katy Wood and James Cornwell, an honours student at the University of New South Wales, have commissioned the stopped-flow sample environment.Koala (Laue Diffractometer)
Koala images can now be processed via a scripted interface which allows users to undertake data-reduction in a streamlined manner for small unit cells. Recent users have had considerable success in refining models for structures with primitive cell edges of the order of 15 Å or less.
Studies of intracrystalline water cluster geometries within pharmaceutical materials form the focus of a post-doctoral project being undertaken by Katharina Fucke in the laboratories of Jon Steed and Judith Howard, Department of Chemistry, University of Durham.
In April, Katharina resolved the image below of three water molecules per molecule of a pharmaceutical material form six membered rings analogous to those formed in ice. The extended hydrogen bonding connects each cluster to neighbouring molecules of the pharmaceutical, the rings thus being isolated from each other.
Intracrystalline water clusters within a single-crystal pharmaceutical material
Software is under development to improve data reduction procedures for larger unit cells. Where these are of interest, potential users should discuss their projects with the instrument scientists to ascertain whether data of suitable quality for the desired purpose may be obtained – for example - we have extracted data for a potential catalyst material from the laboratory of Michael Gardiner, University of Tasmania, from which the presence of an hydridic hydrogen atom is clearly demonstrated. In this case the data reduction was compromised by a larger cell dimension, but nonetheless, the resolution was sufficient to determine the hydridic nature of the material.
In the Press: A Laue diffraction image taken using our Koala single-crystal diffractometer has been used in the new textbook Essential College Physics, Vol. 2, published by Addison Wesley. The book is written by Profs. Andrew Rex (University of Puget Sound) and Richard Wolfson (Middlebury College). The image, featuring sodium chloride, was taken in 2008 as the first image taken on Koala, during commissioning. It appears in Chapter 23.4, on page 544, under the heading "Evidence for Matter Waves".
Sika (cold three-axis spectrometer)
February heralded the arrival of the Sika major components. Upon delivery, these parts were loaded onto a truck using the Neutron Guide Hall 20 tonne crane before being transported into the Reactor Hall where it is waiting imminent installation.
Kowari (strain scanner)
For the first time, the load frame and furnace were simultaneously used on Kowari. From 19-22 April, primary investigator Nicole Stanford from Deakin University used the setup to study the in situ hot deformation of magnesium-based alloys with the aim of identifying the mechanisms of texture modification to guide future alloy design toward higher ductility alloys that can be readily formed into useful shapes.
The 100 kN load frame with the furnace attachment mounted on Kowari’s sample table
The samples were heated to 300 °C during the tests that we carried out in load control to compensate for thermal expansion. During the actual experiment the furnace was sealed and filled with nitrogen
This experiment would not have been possible without the significant efforts of the Sample Environment and Computing groups, for which the instrument scientists and users are most grateful. Thanks guys!