LoadILLTOF v1¶

LoadILLTOF dialog.

Table of Contents

Summary
Properties
Description
Pulse Intervals
Usage
Source

Warning

LoadILLTOF is deprecated. Use LoadILLTOF version 2 instead.

Properties ¶

Name	Direction	Type	Default	Description
Filename	Input	string	Mandatory	File path of the Data file to load. Allowed extensions: [‘.nxs’]
FilenameVanadium	Input	string		File path of the Vanadium file to load (Optional). Allowed extensions: [‘.nxs’]
WorkspaceVanadium	Input	MatrixWorkspace		Vanadium Workspace file to load (Optional)
OutputWorkspace	Output	MatrixWorkspace	Mandatory	The name to use for the output workspace

Description ¶

Loads an ILL TOF NeXus file into a Workspace2D with the given name.

This loader calculates the elastic peak position (EPP) on the fly. In cases where the dispersion peak might be higher than the EPP, it is good practice to load a Vanadium file.

The property FilenameVanadium is optional. If it is present the EPP will be loaded from the Vanadium data.

To date this algorithm only supports: IN4, IN5 and IN6

Pulse Intervals ¶

For IN4 and IN6 the algorithm also calculates the pulse interval.

For the number of pulses:

IN4: $n_{pulses} = \frac{v_{fc}}{4 v_{bc}}$

where $n_{pulses}$ is the number of pulses from the chopper per rotation, $v_{fc}$ the Fermi chopper speed and $v_{bc}$ the background chopper speed. Background chopper 1 and background chopper 2 must have the same speeds. All speeds are in units of rpm.
IN6: $n_{pulses} = \frac{v_{fc}}{v_{sc}}$

where $n_{pulses}$ is the number of pulses from the chopper per rotation, $v_{fc}$ the Fermi chopper speed and $v_{sc}$ the suppressor chopper speed. All speeds are in units of rpm.

The pulse interval, $T_{pulse}$ in seconds, is then given by,

$T_{pulse} = \frac{60 \textrm{s}}{2 v_{fc}} n_{pulses}$ .

Usage ¶

Example - Load a regular histogram Nexus file: (see LoadILLTOF v2 for more options)

# Regular data file.
dataRegular = 'ILLIN6_151460.nxs'

# Load ILL dataset
ws = Load(dataRegular)

print "This workspace has", ws.getNumDims(), "dimensions and has", ws.getNumberHistograms(), "histograms."

Output:

This workspace has 2 dimensions and has 340 histograms.

Example - Load a histogram Nexus file where the dispersion peak is higher than the elastic peak. An auxiliary vanadium file is needed to locate the elastic peak.: (see LoadILLTOF v2 for more options)

# Data file where the dispersion peak is higher than the elastic peak.
dataDispersionPeak = 'ILLIN5_Sample_096003.nxs'

# Vanadium file collected in the same conditions as the dispersion peak dataset.
vanaDispersionPeak = 'ILLIN5_Vana_095893.nxs'

# Load ILL dispersion peak dataset and a vanadium dataset
ws = Load(dataDispersionPeak, FilenameVanadium=vanaDispersionPeak)

print "This workspace has", ws.getNumDims(), "dimensions and has", ws.getNumberHistograms(), "histograms."

Output:

This workspace has 2 dimensions and has 98305 histograms.

Example - Same example as above, but the vanadium file is loaded in advance. The dataset for the dispersion peak is loaded after, using the auxiliary vanadium workspace.: (see LoadILLTOF v2 for more options)

# Data file where the dispersion peak is higher than the elastic peak.
dataDispersionPeak = 'ILLIN5_Sample_096003.nxs'

# Vanadium file collected in the same conditions as the dispersion peak dataset.
vanaDispersionPeak = 'ILLIN5_Vana_095893.nxs'

# Load the Vanadium
wsVana = Load(dataDispersionPeak)

# Load ILL dispersion peak dataset and a vanadium dataset
wsData = Load(dataDispersionPeak, WorkspaceVanadium=wsVana)

print "The Vanadium workspace has", wsVana.getNumDims(), "dimensions and has", wsVana.getNumberHistograms(), "histograms."
print "The Data workspace has", wsData.getNumDims(), "dimensions and has", wsData.getNumberHistograms(), "histograms."