Guide to Datasets for LaB6
==========================

Raw data
========

File format

The raw file WBT0064304.nx.hdf is in the HDF5 format, see hdfgroup.org

The processed file WBT0064304_LaB6_.xye consists of 3 columns of
ASCII numbers. Comments start with "'" character (used by the Topas
package).

File contents

Raw file contents broadly conform to the NeXus specification, refer
nexusformat.org. A 2-dimensional diffraction pattern is stored as
a frame in /entry1/data/hmm_xy. For axis and geometry information refer
to the NeXus standards.

Processed data
==============

File format

The processed file WBT0064304_LaB6_.xye consists of 3 columns of
ASCII numbers. Comments start with "'" character (used by the Topas
package).

File contents

The processed file columns are:

Column 1: 2 theta angle
Column 2: intensity
Column 3: standard uncertainty in intensity

Using the processed data
========================

Data can be read into any common powder diffraction analysis software.
The comment character may need to be changed.

Deriving processed data from the raw data
=========================================

The processed dataset was derived from the raw data as follows:

1. Each frame was normalised to a common incident intensity
using beam monitor counts for Monitor 2 found in the raw file.

2. Each frame was corrected for variable pixel gain by
multiplying by a correction map. The correction map is in
the HDF5 file vcal_241_sx_2017_10_10.gumtree.hdf at /entry1/data/signal
with variance /entry1/data/variance.

3. Each frame was then summed in the vertical direction to
yield a single value for each 2 theta value, ignoring the top and
bottom 20 pixels.

These steps were carried out using the Wombat Gumtree data reduction
code. Please refer to

https://github.com/Gumtree/Wombat_scripts/tree/18fd369e543a80650bb8a519f9c82e3b29a7c9a2/ExperimentScript/python/Reduction

for the code used.