Accessing Metadata

A large quantity of metadata is stored within the nexus file (i15-1-#####.nxs) for each scan. This includes information such as scan time, ring current and detector integration time etc.

It can be viewed by following the steps below;

The nexus file has the same format as a .hdf5 file. h5py (https://www.h5py.org/) is a useful python package for interfacing with the .nxs files.

Load the file into the "Data Files" pannel on the left hand side of the "DataVis" perspective. Select the file by clicking on the filename.
In the "File" option on the navigation bar, select "View Tree..."
You can expand a given entry to view its value.
Similarly you can view the processing that has been applied to your 2D data to get to the integrated 1D data. This information is stored in the i15-1-#####-clusterProcessing#.nxs file. One of these files is generated for each detector. The entries from 0-9 under "process" contain the information, including values, for each processing step and the order in which they were applied. For more information on data processing in Dawn see /wiki/spaces/I151WEB/pages/1521320