CalFile¶

Summary¶

The CalFile is a calibration file originally created for use in the Ariel powder diffraction data reduction package.

Files using this format with the .cal extension are still used by several algorithms in Mantid.

File Format¶

The file is a simple text file with the following format

#  number  UDET  offset  select  group
   0        611  0.0000000  1    0
   1        612  0.0000000  1    0
   2        601  0.0000000  0    0
            ...
  19     101001 -0.0497075  1    2
  20     101002 -0.3515893  1    2
  21     101003 -0.2803879  0    2
            ...
 349     201001  0.0525040  1    3
 350     201002  0.0538936  1    3
 351     201003  0.0535027  1    3
            ...

The first column is simply an index, the second is a UDET identifier for the detector, the third column corresponds to an offset in $\delta d/d$ (this is usually applied in Mantid using the AlignDetectors algorithm). The fourth column is a flag to indicate whether the detector is selected and should be used in DiffractionFocussing. The fifth column indicates the group this detector belongs to (number >=1), zero is not considered as a group.

Masking¶

The most important columns for masking are the UDET and the select column. The number, offset and group entries are ignored.

Algorithms that work with CalFiles¶

Using CalFiles¶

AlignDetectors will apply the offset from a CalFile while converting the data from time of flight to wavelength.
DiffractionFocussing uses the selection and grouping columns of a CalFile to focus the diffraction data.

Loading and saving CalFiles¶

LoadCalFile will load the CalFile into separate offset, masking and grouping workspaces.
SaveCalFile will save a CalFile from separate offset, masking and grouping workspaces.
MaskWorkspaceToCalFile will save a mask workspace as a CalFile.
ReadGroupsFromFile Reads the groups from a CalFile, and output a 2D workspace containing on the Y-axis the values of the Group each detector belongs to. This is used to visualize the grouping scheme for powder diffractometers.

Creating CalFiles¶

CalibrateRectangularDetectors will output a CalFile if the SaveAs property is set to “Calibration”.
GetDetectorOffsets will output a CalFile if the GroupingFilename is set.
CreateCalFileByNames will create a CalFile with the grouping column set according to a list of bank names.
CreateDummyCalFile creates a CalFile from a workspace. All of the offsets will be zero, and the pixels will be all grouped into one group.

Merging CalFiles¶

MergeCalFiles combines the data contained in two CalFiles, based on the selections offsets, selections and groups can be merged. The matching rows are determined by UDET. Any unmatched records are added at the end of the file.

Category: Calibration