Next topic


This Page

Description of the canSAS2012 data formatΒΆ

Computing power has increased to the point where it is now possible to consider routinely analysing multi-dimensional small angle scattering data. This is of particular value when considering non-azimuthally symmetric data from ordered systems and for the grazing incidence SAS experiments.

One of the first aims of the canSAS [1] (Collective Action for Nomadic Small-Angle Scatterers) forum of users and facility staff was to discuss better sharing of SAS data analysis software. One means of doing so is through common data formats to allow the easy use of different analysis software packages. Having developed an XML based standard for one-dimensional reduced small-angle scattering data, [2] which is in use at multiple facilities, we now present a framework for storage of reduced multi-dimensional data. This not only includes the common concept of storing image data from the detector in 2 dimensions but also adding dimensions for parameters that were varied during the experiment (pressure, concentration, temperature, etc.). This is done in a way so the analysis program can take this into account.

The targeted reduced data should be free from any correctable instrumental effects. We identified the absolute minimum required data objects for analysis, a standard recommended set and a dictionary of optional terms for various types of experiments. The devised hierarchical storage structure is in principle agnostic to the container format. With data of rank 2 and higher we recommend HDF5 as an efficient container and that is what the reference examples are provided for.

The format is still in the consultation and evaluation phase. We present the details of the data format and some examples of usage and welcome comments.

The canSAS (Collective Action for Nomadic Small-Angle Scatterers) forum met in Uppsala, Sweden in July 2012 [3] to discuss standardization of the storage of reduced small-angle scattering of any dimension to be considered for analysis. [4]

This document describes the current specification as an outcome of that meeting.