Energy Resolution of a solid state X-Ray detector

AI Thread Summary
The discussion centers on quantifying the energy resolution of a p-i-n semiconductor x-ray detector, specifically using the formula %Resolution = E FWHM / Ei. The user has calculated a 6% resolution for a peak associated with a Cu K-α line, with a centroid value of 8.04 keV and a full width half maximum (FWHM) of 0.49 keV. They are seeking to relate this resolution to an energy value, concluding that their detector cannot distinguish peaks separated by 490 eV on an event-by-event basis, although average detection is possible. Verification with multiple samples has yielded consistent results, affirming the detector's performance. The conversation emphasizes the importance of understanding energy resolution in the context of x-ray detection.
garyd
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Homework Statement


Hi all,
I have been given the task of quantifying the energy resolution of a p-i-n semi-conductor x-ray detector and present it as a value in electron volts

Homework Equations


%Resolution=E FWHM / Ei
Where E FWHM is the full width half maximum of a peak and Ei is the centroid value of that peak[/B]

The Attempt at a Solution


I can calculate % Resolution no problem, but I need to relate it to an energy value. My detector is connected to a multi-channel analyzer that has 4000 channels. Say I have a calculated a %Resolution of 6% for a certain peak value. 6% of 4000 channels =240. I'm not sure where to go from here. The x-ray unit has an anode voltage of 35keV.
Any help would be appreciated
 
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Still working on this and now I'm wondering if my detector energy resolution is the fraction of full width half max of the centroid value? I should also state that I have obtained a counts Vs. energy spectrum of the characteristic x-rays from a copper sample. I have identified the K-α line and applied a normal distribution curve to the data. I have obtained the mean value, i.e. the centroid value and have also determined the full width half maximum energy value. The centroid value obtained for Cu K-α line =8.04 keV and FWHM=0.49 keV. So energy resolution of my detector for this energy is 490keV?
 
If your resolution is 6% of the energy of the specific peak, then you need the energy corresponding to this peak to get the absolute resolution.
garyd said:
The centroid value obtained for Cu K-α line =8.04 keV and FWHM=0.49 keV. So energy resolution of my detector for this energy is 490keV?
Sounds good. Try to verify this with other peaks, if possible.
 
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mfb said:
If your resolution is 6% of the energy of the specific peak, then you need the energy corresponding to this peak to get the absolute resolution.Sounds good. Try to verify this with other peaks, if possible.
I have verified the results for five different samples and the numbers look good, So am I correct in thinking that at this energy my detector can not distinguish two peaks that are separated by 490 eV
 
Not on an event-by-event basis, but if you have many events you can see where the average is for a single peak - or you can see the source is not a single peak, and identify the magnitude of both peaks separately.
 
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