AlignDetectors v1¶
Warning
AlignDetectors is deprecated (on 2021-01-04). Use ConvertUnits instead.
Summary¶
Performs a unit change from TOF to dSpacing, correcting the X values to account for small errors in the detector positions.
See Also¶
Properties¶
Name |
Direction |
Type |
Default |
Description |
---|---|---|---|---|
InputWorkspace |
Input |
Mandatory |
A workspace with units of TOF |
|
OutputWorkspace |
Output |
Mandatory |
The name to use for the output workspace |
|
CalibrationFile |
Input |
string |
Optional: The .cal file containing the position correction factors. Either this or OffsetsWorkspace needs to be specified. Allowed extensions: [‘.h5’, ‘.hd5’, ‘.hdf’, ‘.cal’] |
|
CalibrationWorkspace |
Input |
Optional: A Workspace containing the calibration information. Either this or CalibrationFile needs to be specified. |
||
OffsetsWorkspace |
Input |
OffsetsWorkspace |
Optional: A OffsetsWorkspace containing the calibration offsets. Either this or CalibrationFile needs to be specified. |
Note
As of 2021-01-04, this algorithm is officially deprecated. As a result, developers and users are recommend to use ApplyDiffCal, followed by ConvertUnits, followed by ApplyDiffCal (ClearCalibration=true) to produce the equivalent results.
Description¶
This algorithm applies a calibration table to convert a workspace from
time-of-flight to dSpacing as described below. The equation in GSAS converts from
d-spacing (
The manual describes these terms in more detail. Roughly,
Measuring peak positions using a crystal with a very well known lattice constant will give a good value for converting the data. The d-spacing of the data will be calculated using whichever equation below is appropriate for solving the quadratic.
When
For the case of needing to solve the actual quadratic equation
Here the positive root is used when
This algorithm always uses a calibration table which it either reads from the
CalibrationWorkspace property, or uses ConvertDiffCal to produce from the OffsetsWorkspace
.
Note
The workspace that this algorithms outputs is a ragged workspace.
Restrictions on the input workspace¶
The input workspace must contain histogram or event data where the X unit is time-of-flight and the Y data is raw counts. The instrument associated with the workspace must be fully defined because detector, source & sample position are needed if an OffsetsWorkspace is provided.
Usage¶
Example: Use offset to move peak in Dspace
ws = CreateSampleWorkspace("Event",NumBanks=1,BankPixelWidth=1)
ws = MoveInstrumentComponent(Workspace='ws', ComponentName='bank1', X=0.5, RelativePosition=False)
wsD = ConvertUnits(InputWorkspace='ws', Target='dSpacing')
maxD = Max(wsD)
offset = GetDetectorOffsets(InputWorkspace='wsD', DReference=2.5, XMin=2, XMax=3)
wsA = AlignDetectors(InputWorkspace='ws', OutputWorkspace='wsA', OffsetsWorkspace='offset')
maxA = Max(wsA)
print("Peak in dSpace {:.11f}".format(maxD.readX(0)[0]))
print("Peak from calibration {:.10f}".format(maxA.readX(0)[0]))
Output:
Peak in dSpace 2.66413186052
Peak from calibration 2.5622683421
Categories: AlgorithmIndex | Diffraction\Calibration | Deprecated
Source¶
C++ header: AlignDetectors.h
C++ source: AlignDetectors.cpp