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RemoveExpDecay v1

Summary

This algorithm removes the exponential decay from a muon workspace.

See Also

Fit

Properties

Name	Direction	Type	Default	Description
InputWorkspace	Input	MatrixWorkspace	Mandatory	The name of the input 2D workspace.
OutputWorkspace	Output	MatrixWorkspace	Mandatory	The name of the output 2D workspace.
Spectra	Input	int list		The workspace indices to remove the exponential decay from.

Description

This algorithm removes the exponential time decay from the specified muon spectra, leaving the rest unchanged. By default, all the spectra in a workspace will be corrected. If the detector records a total of zero counts (i.e. the detector is dead) then the output will be all zeros for that detector.

The formula for removing the exponential decay is given by:

\[\textrm{NewData} = (\textrm{OldData}\times{e^\frac{t}{\tau}})/N_0 - 1.0\]

where \(\tau\) is the muon lifetime (2.1969811e-6 seconds). \(N_0\) is a fitted normalisation constant.

Usage

Example - Removing exponential decay:

y = [100, 150, 50, 10, 5]
x = [1,2,3,4,5,6]
input = CreateWorkspace(x,y)

output = RemoveExpDecay(input)

print("Exp. decay removed: {}".format(output.readY(0)))

Output:

Exp. decay removed: [-0.24271431  0.79072482 -0.05900907 -0.70331658 -0.76614798]

Example - Removing exponential decay with dead detector:

import numpy as np
import random

# create data
x=np.linspace(start=0,stop=10,num=5)
xData = np.append(x,x)
xData = np.append(xData,xData)

#make y data
def genYData(x,phi):
  return np.sin(5.0*x+phi)+np.exp(-x/2.2)

yData = np.append(genYData(x, 0.0), genYData(x, 1.2))
yData = np.append(yData, np.zeros(len(x))) # dead detector
yData = np.append(yData, genYData(x, 3.4))

# create workspace
ws = CreateWorkspace(xData,yData,NSpec=4, UnitX="Time")
label=ws.getAxis(0).setUnit("Label")
label.setLabel("Time","microsecond")

output = RemoveExpDecay(ws)# Print the result
for j in range(4):
    print ("Exp. decay removed: {}".format(output.readY(j)))

Output:

Exp. decay removed: [  0.04103434  -0.17277399  -1.29718867  -6.20972864 -25.84444803]
Exp. decay removed: [-0.12586409  0.73213038  3.31216989 11.02723309 33.95108191]
Exp. decay removed: [0. 0. 0. 0. 0.]
Exp. decay removed: [ 0.05933294 -0.42223811 -1.30901512 -2.13214736  1.38620519]

Categories: AlgorithmIndex | Muon

Source

C++ header: RemoveExpDecay.h

C++ source: RemoveExpDecay.cpp