Engineering_Diffraction.rst

Engineering Diffraction
=======================

.. contents:: Table of Contents
  :local:

Overview
--------

This custom interface integrates several tasks related to engineeering
diffraction. It provides functionality for calibration, focusing, and
pre-processing of event mode data. Further extensions can be expected
for next releases as it is under active development. Feedback is very
much welcome. The following sections describe the different tabs or
functionality areas of the interface.

.. interface:: Engineering Diffraction
  :align: center
  :width: 400

General options
^^^^^^^^^^^^^^^
Instrument
 Select the instrument. Only ENGIN-X (ISIS) is supported in this version.

?
  Shows this documentation page.

Close
  Close the interface

RB Number
  To enable the GUI specify a RB Number

Calibration
-----------

This tab provides a graphical interface to calculate calibrations and
visualize them.

It is possible to load an existing calibration (as a CSV file) and to
generate a new calibration file (which becomes the new current
calibration).

Parameters
^^^^^^^^^^

These parameters are required to generate new calibrations:

Vanadium #
  Number of the vanadium run used to correct calibration and experiment
  runs.

Calibration sample #
  Number of the calibration sample run (for example Ceria run) used to
  calibrate experiment runs.

Focus
-----

Here it is possible to focus run files, by providing a run number or a
range of run number to enable multi-run focusing, along with that the
user may also select the files with the help of Browse button.

The focusing process uses the algorithm :ref:`EnggFocus
<algm-EnggFocus>`. In the documentation of the algorithm you can find
the details on how the input runs are focused.

The interface will also create workspaces that can be inspected in the
workspaces window:

1. The *engggui_focusing_input_ws workspace* for the data being focused
2. The *engggui_focusing_output_ws... workspace* for the corresponding
   focused data (where the ... denotes a suffix explained below).

Three focusing alternatives are provided:

1. Normal focusing, which includes all the spectra from the input run.
2. Cropped focusing, where several spectra or ranges of spectra can
   be specified, as a list separated by commas.
3. Texture focusing, where the *texture* group of detectors is given
   in a Detector Grouping File.

Depending on the alternative chosen, the focusing operation will
include different banks and/or combinations of spectra (detectors). In
the firs option, normal focusing, all the selected banks and all the
spectra present in the input runs are considered. In the second
alternative, cropped focusing, all the banks are considered in
principle but only a list of spectra provided manually are
processed. In the third option, *texture focusing*, the banks are
defined by a user-defined list of banks and corresponding spectrum IDs
provided in a file. For these alternatives, the output focused
workspace will take different suffixes: *_bank_1, _bank_2*, and so on
for normal focusing, *_cropped* for cropped focusing, and
*_texture_bank_1, _texture_bank_2*, and so on for texture focusing
(using the bank IDs given in the detector grouping file).

Cropped focusing and Texture focusing have been disabled by default to
declutter the interface, but each section can be enabled simply by
ticking the check-box next to Focus Cropped and Focus Texture.

For texture focusing, the detector grouping file is a text (csv) file
with one line per bank. Each line must contain at least two numeric
fields, where the first one specifies the bank ID, and the second and
subsequent ones different spectrum numbers or ranges of spectrum
numbers. For example::

   # Bank ID, spectrum numbers
   1, 205-210
   2, 100, 102, 107
   3, 300, 310, 320-329, 350-370

When a focus run process is being carried out, Focus Stop button will
be enabled. Focus Stop button will allow the user to abort once the
current focus run process has been completed. Inside the *Result Log*
a warning message will be displayed with last successful run and total
number of focus runs that could not be processed.

Run-Number
^^^^^^^^^^
The run provided to focus can be for example 228061-228063, this will
run all the files within the given range as long as the file
directories are included in the
`User Directories <http://www.mantidproject.org/SplittersWorkspace>`_.
The user may also provide an input of 228061-3 or 228061, 228062,
2280623 which should work the same way.

If a red star sign is displayed next to the Browse Button, it is mostly
likely because the file specified has not been found. Error message
can be viewed by hovering over the red star sign.

Output
^^^^^^

Under the output section, the user is provided with an option of
plotting data in three different formats. One Window - Replacing
Plots: will replace the previous graph and plot a new graph on top.
One Window - Waterfall: will plot all the generated focused
workspace graphs in one window which can be useful while comparing
various graphs. The Multiple Windows: will plot graph in
separate windows. However, user may also change the Plot Data
Representation drop-down box while a run is being carried out. This
will update the interface and plot workspace according to the new
given input. For example, if a user has selected One Window -
Replacing Plots and then decides to change it to One Window -
Waterfall during a run, the interface will carry on by plotting
Waterfall within the same window.

The user also has an option of generated GSS, XYE and OpenGenie
formatted file by clicking the Output Files checkbox. This will
generated three different files for each focused output workspace
in Mantid. These files can be found with appropriate name at location:
C:\EnginX_Mantid\User\236516\Focus on Windows, the
EnginX_Mantid folder can be found on Desktop/Home on other platforms.

Pre-processing
--------------

.. warning:: This is a new capability that is currently in a very
             early stage of definition and implementation. Not all
             options may be supported and/or consistent at the moment.

The focusing options can be applied directly to histogram data. For
event mode experiments, the event data (which would be loaded as event
workspaces in Mantid) need to be pre-processed.

The simplest pre-processing option is "regular time binning" which
will produce a histogram data workspace (as a :ref:`Workspace2D
<Workspace2D>`). The only parameter required is the bin width. The
workspace will be named with the following convention:

- *engggui_preproc_time_ws*

When the input run file contains multiple workspaces (it would be
loaded by :ref:`Load <algm-Load>` as multiple :ref:`EventWorkspace
<EventWorkspace>` workspaces) the output workspace will be a group
with the corresponding number of histogram workspaces, binned
separately. This is the case when the input run file comes from a
multi-period experiment. Note that the time bin can be a multiple of
the pulse time.

A different way of pre-processing event data is by rebinning
multi-period data by pulse times. In this case the input required is
the time step for the binning (the x axis of the output will be time
instead of time-of-flight). It is also possible to specify the number
of periods that will be processed (starting from the first one). This
type of pre-processing produces workspaces with the following naming
convention:

- *engggui_preproc_by_pulse_time_ws*

This tab uses the algorithms :ref:`Rebin <algm-Rebin>` and :ref:`Rebin
<algm-RebinByPulseTimes>` to bin the data in different ways when
converting event data into histogram data.

Settings
--------

Controls several settings, including the input folders where the
instrument run files can be found. Other advanced options can also be
controlled to customize the way the underlying calculations are
performed.

Calibration Parameters
^^^^^^^^^^^^^^^^^^^^^^

The calibration settings are organized in three blocks:

1. Input directories
2. Pixel calibration
3. Advanced settings

The input directories will be used when looking for run files
(Vanadium and Ceria). They effectivel ybecome part of the search path
of Mantid when using this interface.

The pixel calibration file contains the calibration of every pixel of
all banks, as produced by the algorithm :ref:`EnggCalibrateFull
<algm-EnggCalibrateFull>`.

The Following advanced settings are available to customize the
behavior of this interface:

Force recalculate
  If this is enabled, Vanadium corrections will be recalculated even
  if previous correction results are available for the current Vanadium
  run number. This is not required unless a modification is done to the
  original Vanadium run file, or there is a change in the algorithms
  that calculate the corrections

Tempalte .prm file
  By changing this option you can Use a different template file for the
  output GSAS IPAR that is generated in the Calibration tab.

Rebin for Calibrate
  This sets a rebin width parameter that can be used by underlying
  algorithms such as :ref:`EnggCalibrate <algm-EnggCalibrate>` and
  :ref:`EnggFocus <algm-EnggFocus>`

Algorithms
----------

Most of the functionality provided by this interface is based on the
engineering diffraction Mantid algorithms (which are named with the
prefix *Engg*). This includes :ref:`EnggCalibrate
<algm-EnggCalibrate>`, :ref:`EnggCalibrateFull
<algm-EnggCalibrateFull>`, :ref:`EnggVanadiumCorrections
<algm-EnggVanadiumCorrections>`, :ref:`EnggFocus <algm-EnggFocus>`,
and several other algorithms, explained in detail in the Mantid
algorithms documentation.

.. categories:: Interfaces Diffraction