Quokka
Quokka commissioning achieved an important milestone in March with the successful conversion of scattering data to an absolute scale over the whole range of available camera lengths (1.3 20m). The figure shows absolutely normalized merged data sets from three different configurations of the Quokka instrument, achieved using a modified version of the IGOR-based data-reduction and analysis suite written by Steve Kline at the NIST-Center for Neutron Research. The measurements are of a binary paraffin mixture: a 2:1 molar mixture of two normal-alkanes of 28 and 36 carbons for which the longer chain has been deuterated. The data cover a Q range from 0.003 to 0.8 Å-1 and the total data collection time was 4.5 hours. We have recently installed a focusing MgF2 lens and prism optical system which will allow Quokka to reach its low Q design limit of 0.0008 Å-1. We are also planing to modify the detector window geometry to achieve a high Q limit of about 1.3 Å-1.
Merged Quokka data: red points are a low Q configuration with detetor at 20m; green with detector at 10m; blue is the high Q configuration with detector at 4m from the sample position.