GBS Elektronik MCA166-USB - Manual (Page 32)

MCA166-USB
APPENDIX 2 - MCA166-USB algorithm, formulas
This appendix lists the algorithms used by the MiniMCA for the following functions:
●
Area, Area uncertainty
●
Centroid
●
FWHM
●
Smooth
●
Strip
●
Energy Calibration
The Area and the Area Uncertainty Function:
The area algorithm calculates the number of counts above the background in a ROI.
The background area is determined by averaging 4 points on both sides of the peak
(the ROI limit points and 3 outer points) and linear fit:
Area = Integral - Background
Background =
( ) ( )
∑ ∑ +
= − =
+
+ −
3
3
*
8
1
end
end
begin
begin
ROI
ROI i i
ROI
ROI i i
begin end Spectrum Spectrum
ROI ROI
Integral = Spectrum
i
i ROI
ROI
begin
end
=
∑
Area Uncertainty =
( )
Integral Spectrum Spectrum
ROI ROI
i i
ROI
ROI
i ROI
ROI
end begin
end
end
begin
begin
+ +





 ∗
− +
















+
= −
∑ ∑
3
3
2
1
8
where,
Spectrum
i
= the absolute number of counts in channels i
ROI
begin
= the ROI’s start channel
ROI
end
= the ROI’s stop channel
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