4.2

RemoveExpDecay v1

../_images/RemoveExpDecay-v1_dlg.png

RemoveExpDecay dialog.

Summary

This algorithm removes the exponential decay from a muon workspace.

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++ source: RemoveExpDecay.cpp (last modified: 2019-07-17)

C++ header: RemoveExpDecay.h (last modified: 2019-10-28)