Reproducibility and Reliability Working Group
Reliability and Reproducibility
The group considers the issues that relate to reliability of results from small-angle scattering experiments, both as regards measured data and the parameters derived from analysis of the data that describe the samples. It had been established originally under the name 'Standardization' but has been renamed to provide a better description of the activities.
- John Barker (NIST)
- Peter Boesecke (ESRF Contact)
- Rex Hjelm (LANSCE)
- Jan Ilavsky (APS)
- Peter Lindner (ILL)
- Marc Malfois (Alba)
- Adrian Rennie (Uppsala University - chair)
- August 2015. The mailing list is now on Google Groups https://groups.google.com/forum/#!forum/cassas-rrwg. A summary of recent activities will be presented at the lunch time session at the SAS2015 meeting in Berlin on Monday September 14, 2015.
- A short account of the discussion concerning this topic at the canSAS-VIII meeting from 14 to 16 April 2015 in Tokai is available:
Plans are being made (April 2015) for further types of sample to be circulated for comparative measurements.
- Discussion at the workshop in Uppsala has been presented on a separate page:
- Work was presented at the SAS-2012 conference (www.sas2012.com). This include a summary of standardization in the canSAS session and a presentation on the latex round robin measurements.
Glassy Carbon Round Robin
Two samples of glassy carbons from Jan Ilavsky have been doing the rounds. They've been to NIST, ILL, ISIS, APS, ESRF and Diamond and ANSTO.
Details and data here : Glassy Carbon Round Robin
Polystyrene Latex Round Robin
Samples of a monodisperse polystyrene latex have recently been measured at ILL (D22 and D11), ANSTO (Quokka), ISIS (SANS2D) and at NCNR (NG7). Samples are also at Diamond awaiting measurement. Details and data here : Latex Round Robin
A new series of samples designated J, K, L and that have slightly different dilution have been provided for measurements at APS, FRMII, SPRING-8 and ILL.
Results of measurements with some conclusions are described in a publication in Journal of Applied Crystallography:
A. R. Rennie, M. S. Hellsing, K. Wood, E. P. Gilbert, L. Porcar, R. Schweins, C. D. Dewhurst, P. Lindner, R. K. Heenan, S. E. Rogers, P. D. Butler, J. R. Krzywon, R. E. Ghosh, A. J. Jackson and M. Malfois 'Learning about SANS instruments and data reduction from round robin measurements on samples of polystyrene latex', Journal of Applied Crystallography, 46, (2013). doi: 10.1107/S0021889813019468 .
We will try to gather summaries of the procedures used for calibration of small-angle scattering instruments. It has been suggested that summaries of information would benefit both users and those who run instruments and facilities. Everyone is encouraged to contribute to this work in progress. Procedures for laboratory instruments as well as sycnchrotron and neutron facilities are welcome.
Details are here : Calibration Procedures