Count rates from X-ray Fluorescence Spectrum

In summary: If you integrate just the gaussian peak, and the widths of the other peaks are not known, then you might not be able to correctly determine the count-rate for those peaks.
  • #1
hhhmortal
176
0
My question is, when extracting the count rate from a particular peak in the energy dispersive spectrum (e.g. X-ray fluorescence) Is this done by simply drawing a straight horizontal line from the top of the peak to the y-axis and the corresponding intercept will be the count rate? What if the peak has a large spectral width (i.e. large FWHM), does this change the count rate for that peak?



Thanks
 
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  • #2
Can anyone provide a yes or no answer at least? :/
 
  • #3
Sorry .. missed your post before. Anyway, I think you need to integrate the peak to get the total intensity. Basically, if you just draw the line you described, I think you would only know the count-rate at max intensity. I am not that familiar with X-ray fluorescence data, so I can't really say more than that off the top of my head. I don't know the conventions of the field for describing data to others. It is possible that the count-rate at max intensity is the proper way to report data ... that can sometimes be just fine if all your peaks have the same shapes and the peak width is constant (or at least doesn't change much). However if you are comparing peaks or spectra with drastically different peak-widths, then it doesn't seem correct to mention only the max count rate.

Are your peaks gaussian or Lorentzian shaped, or are they some other shape entirely?
 
  • #4
They are gaussian. I'm just curious how this is done in practise. I assume as you mentioned, the gaussian is just integrated to get the total count rate. Of course the smaller the FWHM the more accurate it would be to just read the count rate at max-intensity.Thanks, this has helped!
 
  • #5
hhhmortal said:
They are gaussian. I'm just curious how this is done in practise. I assume as you mentioned, the gaussian is just integrated to get the total count rate. Of course the smaller the FWHM the more accurate it would be to just read the count rate at max-intensity.


Thanks, this has helped!

Glad to help .. just one additional point that might need clarification .. it doesn't matter so much if the peaks are narrow or broad, what matters is that they all have the same width (within some acceptable tolerance). Since the peaks are gaussian, if they all have the same width, then the ratios of their areas are identical to the ratios of their maximum heights.
 

What is an X-ray Fluorescence Spectrum?

An X-ray Fluorescence Spectrum is a graphical representation of the characteristic x-rays emitted from a material when it is bombarded with high-energy x-rays. It shows the energy or wavelength of the emitted x-rays on the x-axis and the count rate or intensity on the y-axis.

What is a count rate in X-ray Fluorescence Spectroscopy?

A count rate is the number of x-rays detected by the instrument in a given amount of time. It is measured in counts per second (cps) or counts per minute (cpm) and is directly related to the intensity of the x-rays emitted from the sample.

How is the count rate calculated from an X-ray Fluorescence Spectrum?

The count rate is calculated by dividing the total number of counts detected by the instrument by the amount of time it took to collect the data. This gives the average number of counts per second or minute and represents the intensity of the x-rays emitted from the sample.

What factors can affect the count rate in an X-ray Fluorescence Spectrum?

The count rate can be affected by several factors such as the concentration of the elements in the sample, the thickness and density of the sample, the type of x-ray source used, and the efficiency of the detector. Additionally, any background radiation or interference from other elements can also affect the count rate.

Why is it important to consider count rates in X-ray Fluorescence Spectroscopy?

Count rates are important in X-ray Fluorescence Spectroscopy as they provide valuable information about the elements present in a sample and their relative concentrations. It also helps in determining the accuracy and sensitivity of the instrument and can be used to optimize the experimental conditions for better results.

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