I already characterized my samples for X-Ray diffraction but peaks are too noisy and i think reason is scan rate. i used 0.1 scan rate for XRD characterization but results are not satisfactory, they have too much noise. please suggest me possible reasons of that noise and how they are linked with scan rate?
Dear Usman,
the incomming flow of x-rays onto your detector is governed by Poission statistics. (Please see the section 'Noise and SNR' at the attached link).Thus your noise is easily calculated by the square root of your counts N in your diffractogram: mean noise = sqrt(N) and your noise relative to your signal N is given by : rel-noise = sqrt(N)/N = sqrt(1/N).
So when you will decrease the relative noise by a factor of two you have to increase the your counts N by a factor of four; thus decreasing the scan rate by a factor of four.
For a decrease of relative noise by a factor of three you have to increase your counts by a factor of 9 thus decrease your scan rate by a factor of 9.
For decreasing the relative noise by a factor of 10 you have to decrease your scan rate by a factor of 100......... and so forth.
You may also increase the tube parameters (mA setting and Voltage) and enlarge slit widths to get more x-ray flux. But please ask the operator of your XRD system whether such changes are recommended at all in your case.
http://xrayphysics.com/snr.html
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