3.7

SCDPanelErrors

Description

This fit function is used for calibrating RectangularDetectors by adjusting L0, time offset, panel width, panel height, panel center, panel orientation, and allow for the sample being offset from the instrument center.

Workspace

A Workspace2D with 1 spectra. The xvalues of the spectra are for each peak, the peak index repeated 3 times. The y values are all zero and the errors are all 1.0

This spectra may have to be copied 3 times because of requirements from the fitting system.

Output

The argument out from function1D ,for each peak, gives the error in qx, qy, and qz. The theoretical values for the qx, qy and qz are found as follows:

  • Calculating the best fitting UB for the given indexing and parameter values
  • Find U
  • The theoretical UB is then U*B0 where B0 is formed from the supplied lattice parameters
  • The theoretical qx,qy,and qz can be obtained by multiplying the hkl for the peak by this matrix(/2π)

Attributes (non-fitting parameters)

Name Type Default Description
a     The lattice parameter a in Angstroms
b     The lattice parameter b in Angstroms
c     The lattice parameter c in Angstroms
alpha     The lattice parameter alpha in degrees
beta     The lattice parameter beta in degrees
gamma     The lattice parameter gamma in degrees
PeakWorkspaceName     The name of the PeaksWorkspace
NGroups     The number of grouping of banks to be considered
BankNames     List of banknames to group.
startX     -1 or starting position in the workspace to start calculating the outputs
endX     -1 or 1+ ending position in the workspace to start calculating the outputs
RotateCenters Boolean   If false Rotations are only about the center of the banks.
SampleOffsets Boolean   A sample being off from the center of the goniometer can result in larger errors.
  • PeakWorkspaceName - This peak must be indexed by a UB matrix whose lattice parametersare CLOSE to the above lattice paramters
  • BankNames - Names separated by “/” or a ”!” if the next bank is in a different group. Bank names from the same group belong together(“Requirement” for use with the Fit algorithm)

Properties (fitting parameters)

Name Default Description
f0_detWidthScale 1.0 panel Width
f0_detHeightScale 1.0 panel Height
f0_Xoffset 0.0 Panel Center x offset
f0_Yoffset 0.0 Panel Center y offset
f0_Zoffset 0.0 Panel Center z offset
f0_Xrot 0.0 Rotation(degrees) Panel Center in x axis direction
f0_Yrot 0.0 Rotation(degrees) Panel Center in y axis direction
f0_Zrot 0.0 Rotation(degrees) Panel Center in z axis direction
l0 0.0 Initial Flight Path
t0 0.0 Time offset
SampleX 0.0 Sample x offset
SampleY 0.0 Sample y offset
SampleZ 0.0 Sample z offset
  • l0- the initial Flight path in units from Peak.getL1
  • t0-Time offset in the same units returned with Peak.getTOF)
  • SampleX-Sample x offset in the same units returned with Peak.getDetPos().norm()
  • SampleY-Sample y offset in the same units returned with Peak.getDetPos().norm()
  • SampleZ-Sample z offset in the same units returned with Peak.getDetPos().norm()
  • f*_detWidthScale-panel Width for Group* in the same units returned with Peak.getDetPos().norm()
  • f*_detHeightScale-panel Height for Group* in the same units returned with Peak.getDetPos().norm()
  • f*_Xoffset-Panel Center x offsets for Group* banks in the same units returned with Peak.getDetPos().norm()
  • f*_Yoffset-Panel Center y offsets for Group* banks in the same units returned with Peak.getDetPos().norm()
  • f*_Zoffset-Panel Center z offsets for Group* banks in the same units returned with Peak.getDetPos().norm()
  • f*_Xrot-Rotations(degrees) for Group* banks around “Center” in x axis direction
  • f*_Yrot-Rotations(degrees) for Group* banks around “Center” in y axis direction
  • f*_Zrot-Rotations(degrees) for Group* banks around “Center” in z axis direction
  • SampleX -sample X offset in meters(Really Goniometer X offset)
  • SampleY- sample Y offset in meters
  • SampleZ- sample Z offset in meters

The order of rotations correspond to the order used in all of Mantid.

Categories: FitFunctions | Calibrate

Source

C++ source: SCDPanelErrors.cpp

C++ header: SCDPanelErrors.h