# Energy Resolution of a solid state X-Ray detector

1. Oct 23, 2014

### garyd

1. The problem statement, all variables and given/known data
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

2. Relevant 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

3. 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

2. Oct 23, 2014

### garyd

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?

3. Oct 23, 2014

### Staff: Mentor

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.

4. Oct 24, 2014

### garyd

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

5. Oct 24, 2014

### Staff: Mentor

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.