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MagFormFactorCorrection v1

Summary

MagFormFactorCorrection corrects a workspace for the magnetic form factor F(Q) by dividing S(Q,w) by F(Q)^2.

See Also

SofQW

Properties

Name	Direction	Type	Default	Description
InputWorkspace	Input	MatrixWorkspace	Mandatory	Workspace must have one axis with units of Q
OutputWorkspace	Output	MatrixWorkspace	Mandatory	Output workspace name.
IonName	Input	string	Cu2	The name of the ion: an element symbol with a number indicating the valence, e.g. Fe2 for Fe2+ / Fe(II). Allowed values: [‘Au5’, ‘Au2’, ‘Au1’, ‘Pt6’, ‘Pt4’, ‘Pt3’, ‘Pt2’, ‘Ir6’, ‘Au4’, ‘Ir4’, ‘Pd1’, ‘Pd0’, ‘Pr3’, ‘Np4’, ‘Mo0’, ‘Rh0’, ‘Ir5’, ‘Zr1’, ‘Y0’, ‘Eu2’, ‘Tm2’, ‘Zr0’, ‘Ce2’, ‘Fe1’, ‘Gd2’, ‘U5’, ‘Re0’, ‘Cu3’, ‘Am4’, ‘Mo1’, ‘Mn2’, ‘Cu2’, ‘Cr3’, ‘Cu0’, ‘Ni4’, ‘Ni1’, ‘Tc0’, ‘U3’, ‘Ni0’, ‘Rh1’, ‘Nb1’, ‘Re6’, ‘Fe3’, ‘Tc1’, ‘Ti3’, ‘Cr4’, ‘Yb2’, ‘Fe0’, ‘Yb3’, ‘Cu1’, ‘Ni3’, ‘Ir1’, ‘Ni2’, ‘W0’, ‘W1’, ‘Ti0’, ‘Co3’, ‘Am7’, ‘Co1’, ‘V4’, ‘Pu3’, ‘Ti2’, ‘Mn3’, ‘Mn0’, ‘Co2’, ‘Cu4’, ‘Er2’, ‘V2’, ‘Ta3’, ‘Ce3’, ‘Sc1’, ‘Cr1’, ‘V1’, ‘Ta4’, ‘Mn4’, ‘W5’, ‘Ir2’, ‘Np6’, ‘Cr2’, ‘Ru0’, ‘Np5’, ‘W3’, ‘V0’, ‘Au3’, ‘Fe2’, ‘V3’, ‘Tm3’, ‘Mn1’, ‘Ti1’, ‘Nd3’, ‘Fe4’, ‘Nd2’, ‘Sm2’, ‘Sm3’, ‘Eu3’, ‘Os3’, ‘Gd3’, ‘Tb3’, ‘Tb2’, ‘Dy2’, ‘Hf3’, ‘Am5’, ‘Os6’, ‘Pt1’, ‘Dy3’, ‘Ho2’, ‘Os2’, ‘Ho3’, ‘Pu5’, ‘Re3’, ‘Er3’, ‘U4’, ‘Ir0’, ‘Np3’, ‘Cr0’, ‘Os7’, ‘Pu4’, ‘Pu6’, ‘Co4’, ‘Ir3’, ‘Am2’, ‘Re2’, ‘Am3’, ‘Sc2’, ‘Os1’, ‘Am6’, ‘Hf2’, ‘Ta2’, ‘Co0’, ‘Re4’, ‘Pt5’, ‘W2’, ‘Ru1’, ‘Re5’, ‘Nb0’, ‘Sc0’, ‘W4’, ‘Re1’, ‘Os0’, ‘Os4’, ‘Os5’]
FormFactorWorkspace	Output	MatrixWorkspace		If specified the algorithm will create a 1D workspace with the form factor vs Q with a name given by this field.

Description

Scales the InputWorkspace by \(1/|F(Q)|^2\) where \(F(Q)\) is the magnetic form factor for the ion specified in IonName.

IonName must be specified as a string with the element name followed by a number which indicates the charge / oxidation state. E.g. Fe2 indicates \(\mathrm{Fe}^{2+}\) or Fe(II).

Restrictions on the Input Workspace

The input workspace must have one axis with units of MomentumTransfer.

Usage

Note

To run these usage examples please first download the usage data, and add these to your path. In Mantid this is done using Manage User Directories.

ISIS Example

The following code will run a reduction on a MARI (ISIS) dataset and apply the algorithm to the reduced data. The datafiles (runs 21334, 21337, 21346) and map file ‘mari_res2013.map’ should be in your path. Run number 21337 is a measurement of a PrAl3 sample from the neutron training course. The single crystal field excitation around 4.5 meV should have an intensity variation that follows the magnetic form factor. Thus, the integrating between 4 and 5 meV in the corrected workspace should yield a nearly flat line along the \(|Q|\) direction.

from Direct import DirectEnergyConversion
from mantid.simpleapi import *
rd = DirectEnergyConversion.DirectEnergyConversion('MARI')
ws = rd.convert_to_energy(21334, 21337, 15, [-15,0.05,15], 'mari_res2013.map',
    monovan_run=21346, sample_mass=10.62, sample_rmm=221.856, monovan_mapfile='mari_res2013.map')
ws_sqw = SofQW3(ws, [0,0.05,6], 'Direct', 15)
ws_corr = MagFormFactorCorrection(ws_sqw, IonName='Pr3', FormFactorWorkspace='Pr3FF')

Test Example

This example uses a generated dataset so that it will run on automated tests of the build system where the above datafiles do not exist.

import numpy as np
ws = CreateSampleWorkspace(binWidth = 0.1, XMin = 0, XMax = 50, XUnit = 'DeltaE')
ws = ScaleX(ws, -15, "Add")
LoadInstrument(ws, InstrumentName='MARI', RewriteSpectraMap = True)
ws = SofQW(ws, [0, 0.05, 8], 'Direct', 35)
Q = ws.getAxis(1).extractValues()
for i in range(len(Q)-1):
    qv = ( (Q[i]+Q[i+1])*0.5 ) / 4 / np.pi
    y = ws.dataY(i)
    y *= np.exp(-16*qv*qv)
ws_corr = MagFormFactorCorrection(ws, IonName='Fe3', FormFactorWorkspace='Fe3FF')

Categories: AlgorithmIndex | CorrectionFunctions