Initially the fits file was loaded into python, the image was then projected onto the x-axis to obtain a spectrum. This was in the units of N_{adu} against position, so from the eqaution N_{pe} = 2.3*N_{adu} the data was plotted in N_{pe} against position.

  • Cadmium_spectrum.png:

To calculate the background of the data, the position between 350 and 500 was selected, this have a plot of which had a bright pixel as shown,

  • Background with bright pixel:
by ommiting the bright pixel a histogram of the data could be plotted.

  • Background histogram:
The mean and the standard deviation were calculated using the numpy package and were equal to:

mean = 149775.0,

stdev = 20571.1,

however for a poisson distribution where,

f(n,l) = (l^n)( e^{-l})/(n!)

l is equal to the expextation value and the variance, therefore for the distribution to be poisson the mean should be equal to the square of the standard deviation.

Spectrum with removed background

The background could then be reomved from the inital spectra of the lamp leaving only the significant peaks. This was done by removing the mean+stdev.

  • Cadmium_removedBackground.png:
-- JosephBayley - 13 Oct 2015
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Topic revision: r3 - 13 Oct 2015 - JosephBayley

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