MCA527
A
MCA527 Algorithm, Formulas
This appendix lists the algorithms used by the MCA 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:
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
i
= channel number
68
Background
=
ROI
end
−
ROI
begin
1
8
∑
i
=
ROI
begin
−
3
ROI
begin
Spectrum
i
∑
i
=
ROI
end
ROI
end
3
Spectrum
i
Integral
=
∑
i
=
ROI
begin
ROI
end
Spectrum
i
Area Uncertainty
=
Integral
∑
i
=
ROI
begin
−
3
ROI
begin
Spectrum
i
∑
i
=
ROI
end
ROI
end
3
Spectrum
i
ROI
end
−
ROI
begin
1
8
2
Area
=
Integral
−
Background
