Commit 8bbd5a50 authored by Whitfield, Ross's avatar Whitfield, Ross
Browse files

Update docs

parent 533929db
......@@ -106,6 +106,9 @@ for selecting between :ref:`GetDetectorOffsets
<algm-GetDetectorOffsets>` and :ref:`GetDetOffsetsMultiPeaks
<algm-GetDetOffsetsMultiPeaks>`.
.. _calibration_tofpd_group_calibration-ref:
Group Calibration
~~~~~~~~~~~~~~~~~
......@@ -115,6 +118,28 @@ the instrument in groups using a combination of :ref:`CrossCorrelate
<algm-GetDetectorOffsets>` and :ref:`PDCalibration
<algm-PDCalibration>`.
It works by performing the cross-correlations on only the detectors
within a group, after which the grouped detectors are merge together
to use with PDCalibration. The difc from the PDCalibration and
cross-correlation are combined using :ref:`CombineDiffCal
<algm-CombineDiffCal>`
The workflow follows these step:
#. Load data, usually diamond
#. Convert to d-spacing
#. CrossCorrelate a portion of the instrument according to the group information
#. GetDetectorOffsets to calculate offsets for individual pixels with a group
#. ConvertDiffCal to convert these constants to :math:`DIFC_{CC}`
#. Use :math:`DIFC_{CC}` to convert the origonal data to d-spacing. DiffractionFocus allows for combining a portion of the instrument into a single spectrum for improved statistics
#. Pick an arbitrary constant, :math:`DIFC_{arb}` to convert this combined spectrum back to time-of-flight
#. PDCalibration the combined spectrum to determine a conversion constant :math:`DIFC_{PD}`
#. Do math (below) to combine :math:`DIFC_{CC}`, :math:`DIFC_{arb}`, and :math:`DIFC_{PD}` into a new calibration constant, :math:`DIFC_{eff}`
.. math::
DIFC_{eff} = \frac{DIFC_{PD}}{DIFC_{arb}} DIFC_{CC}
.. testcode:: group_cal
# create a fake starting workspace in d-spacing then convert to TOF for calibration
......@@ -238,7 +263,8 @@ The evolution in the calibration can be seen with
.. figure:: /images/tofpd_group_calibration.png
:align: center
The same complete calibration can just be run with just ``group_calibration.do_group_calibration``.
The same complete calibration can just be run with just
``group_calibration.do_group_calibration``.
.. testsetup:: group_cal2
......@@ -285,10 +311,10 @@ The same complete calibration can just be run with just ``group_calibration.do_g
5 2318.3
6 2269.5
The resulting diffcal can be saved with :ref:`SaveDiffCal
<algm-SaveDiffCal>`.
The resulting :ref:`diffcal <DiffractionCalibrationWorkspace>` can be
saved with :ref:`SaveDiffCal <algm-SaveDiffCal>`.
.. codeblock::
.. code-block:: python
SaveDiffCal(CalibrationWorkspace=diffcal,
MaskWorkspace=mask,
......
......@@ -14,6 +14,7 @@ Powder Diffraction
New features
############
- New algorithm :ref:`CombineDiffCal <algm-CombineDiffCal>` to calibrate groups of pixels after cross correlation so that diffraction peaks can be adjusted to the correct positions
- New script for doing calibration by groups, :ref:`PowderDiffractionCalibration <calibration_tofpd_group_calibration-ref>`
Improvements
############
......
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