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# RemoveExpDecay v1¶

## Summary¶

This algorithm removes the exponential decay from a muon workspace.

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