ConvertToYSpace v1¶

ConvertToYSpace dialog.

Table of Contents

Summary
Properties
Description
Usage
Source

Summary ¶

Converts workspace in units of TOF to Y-space as defined in Compton scattering field

Properties ¶

Name	Direction	Type	Default	Description
InputWorkspace	Input	MatrixWorkspace	Mandatory	The input workspace in Time of Flight
Mass	Input	number	Mandatory	The mass defining the recoil peak in AMU
OutputWorkspace	Output	MatrixWorkspace	Mandatory	The output workspace in y-Space
QWorkspace	Output	MatrixWorkspace		The output workspace in q-Space

Description ¶

The final unit of the x-axis is changed to momentum (Y) space as defined by the formula:

$Y = 0.2393\frac{M}{\epsilon_i^{0.1}}(\omega - \frac{q^2}{2M})$

where $M$ is the mass in atomic mass units, $\displaystyle\epsilon$ is the incident energy, $\displaystyle\omega$ is the energy change and $q$ is defined as $\sqrt{(k_0^2 + k_1^2 - 2k_0k_1\cos(\theta))}$ .

The TOF is used to calculate $\displaystyle\epsilon_i$ and the $\displaystyle1/\epsilon$ dependence causes an increasing set of TOF values to be mapped to a decreasing set of $\displaystyle Y$ values. As a result the final $Y$ -space values are reversed to give a workspace with monotonically increasing $Y$ values.

Usage ¶

Example - simple convert to Y-space:

###### Simulates Load workspace for and Indirect spectrometer #################
tof_ws = CreateSimulationWorkspace(Instrument='MAR',BinParams=[-50,2,50],UnitX='TOF')
SetInstrumentParameter(tof_ws,ParameterName='t0',ParameterType='Number',Value='0.5')
SetInstrumentParameter(tof_ws,ParameterName='efixed',ParameterType='Number',Value='30.')
###### Convert data to format acceptable by ConvertToYSpace
tof_ws = ConvertToPointData(tof_ws)
###### Convert to Y Space
wsY=ConvertToYSpace(InputWorkspace='tof_ws',Mass='30')
#
# Look at sample results:
print 'part of the converted workspace:'
for i in xrange(0,10): print wsY.readX(0)[i],wsY.readY(0)[i],wsY.readE(0)[i]

Output:

part of the converted workspace:
179247674 4.44978825566 0.0
970903402 4.44292943299 0.0
763039952 4.43608530232 0.0
555655487 4.42925581439 0.0
34874818 4.42244092015 0.0
142316213 4.41564057078 0.0
936357776 4.4088547177 0.0
730871069 4.40208331255 0.0
525854298 4.39532630718 0.0
32130568 4.38858365367 0.0

Categories: Algorithms | Transforms | Units