PDLoadCharacterizations v1

../_images/PDLoadCharacterizations-v1_dlg.png

PDLoadCharacterizations dialog.

Summary

Load a characterization file used in Powder Diffraction Reduction.

Properties

Name Direction Type Default Description
Filename Input string Mandatory Characterizations file. Allowed extensions: [‘.txt’]
ExpIniFilename Input string   (Optional) exp.ini file used at NOMAD. Allowed values: [‘ini’]
OutputWorkspace Output TableWorkspace Mandatory Output for the information of characterizations and runs
IParmFilename Output string   Name of the gsas instrument parameter file.
PrimaryFlightPath Output number   Primary flight path L1 of the powder diffractomer.
SpectrumIDs Output int list   Spectrum Nos (note that it is not detector ID or workspace indices). The list must be either empty or have a size equal to input workspace’s histogram number.
L2 Output dbl list   Secondary flight (L2) paths for each detector. Number of L2 given must be same as number of histogram.
Polar Output dbl list   Polar angles (two thetas) for detectors. Number of 2theta given must be same as number of histogram.
Azimuthal Output dbl list   Azimuthal angles (out-of-plane) for detectors. Number of azimuthal angles given must be same as number of histogram.

Description

This algorithm loads information into a TableWorkspace for the characterization information and a collection of output parameters for the focus positions to be used in EditInstrumentGeometry v1. If a section is missing then those parameters will be empty. This includes an empty table (zero rows) if that information is missing. The resulting TableWorkspace is intented to be used by PDDetermineCharacterizations v1

This algorithm is one of the workflow algorithms that helps SNSPowderReduction v1.

Characterization File

An example from POWGEN shows both of the available portions of a characterization file:

Instrument parameter file:
1 3.18 90.0000
L1 60.0
#S 1 characterization runs
#L frequency(Hz) center_wavelength(angstrom) bank_num vanadium_run empty_run vanadium_back d_min(angstrom) d_max(angstrom)
60 0.533  1 17533 0 0 0.05  2.20  0000.00  16666.67
60 1.066  2 17534 0 0 0.30  4.60  8333.33  25000.00
60 1.333  3 17535 19770 0 0.43  5.40 12500.00  29166.67
60 2.665  4 17536 0 0 1.15  9.20 33333.33  50000.00
60 4.797  5 17537 0 0 2.25 15.35 66666.67  83333.67
60 3.731  6 18280 0 0 1.70 12.50 50000.00  66666.67
10 3.198  1 17538 0 0 0.05 15.40 00000.00 100000.00

The first line Instrument parameter file: must be present to mark the beginning of the first section. Whatever string appears after the semicolon is copied into the IParmFilename output property. The following lines are of the form “bank l2 polar” with the last line being the keyword L1 followed by the effective primary flight path. This information is saved in the IParmFilename, SpectrumIDs, L2, Polar, and PrimaryFlightPath properties. The Azimuthal properties is filled with zeros and is the same length as SpectrumIDs, L2, Polar, and PrimaryFlightPath.

The second section of the characterizations file is read into the output TableWorkspace as described below.

The exp.ini file is specific to the NOMAD instrument at SNS and is optional.

Characterization TableWorkspace

The columns names and types are described in the following table.

Name Type
frequency double
wavelength double
bank int
vanadium int
container int
empty int
d_min str
d_max str
tof_min double
tof_max double

Categories: Algorithms | Workflow\DataHandling