-- AnishaVadher - 13 Oct 2016

• Working out how much background for each pixel
• Plotted a histogram of number of photoelectrons against the frequency for a 0.1s exposure in the dark frame which follows a Gaussian distribution
• Number of photoelectrons = pixel value (ADU) * Gain
• Gain = 2.3 e/ADU (value from PH2900 report)
• From the histogram I will obtain the value at the peak and the error from the FWHM
• Error in the peak = FWHM/2.35
• I will get these statistics for each exposure time in the dark frames that I have taken and plot the peak value as a function of exposure time and the error as a function of exposure time.
• There are big gaps between the bins which I am not sure why.
• Edit - the gaps are due to the fact that the histogram only takes integer values so increasing the number of bins leads to more gaps in the histogram.
• Histrogram of number of photoelectrons for a 0.1s exposure in the dark frame with 45 bins.:

• Also plotted a histogram for the sum of pixel along the x-axis values against frequency for a 0.1s exposure in the dark frame which follows a Poisson distribution
• The histograms from the sum of pixels along the y-axis follows a Gaussian distribution.

• Plotted the median intensity of the pixels as a function of exposure time using the values given from the image using np.median in python. I am yet to work out the errors.

• The median intensity as a function of exposure time.:
Topic attachments
I Attachment History Action Size Date Who Comment
png Histogram_of_number_of_photoelectrons_for_0.1s_exposure.png r1 manage 18.4 K 13 Oct 2016 - 23:58 AnishaVadher Histrogram of number of photoelectrons for a 0.1s exposure in the dark frame.
png Difference_between_summing_across_x-axis_and_y-axis.png r1 manage 38.8 K 14 Oct 2016 - 00:01 AnishaVadher Histograms to show the difference between summing across x-axis and y-axis for 0.1s exposure dark frame
png Histogram_of_number_of_photoelectrons_for_0.1s_exposure_45_bins.png r1 manage 18.7 K 14 Oct 2016 - 11:57 AnishaVadher Histrogram of number of photoelectrons for a 0.1s exposure in the dark frame with 45 bins.
png The_median_intensity_as_a_function_of_exposure_time.png r1 manage 33.1 K 14 Oct 2016 - 12:06 AnishaVadher The median intensity as a function of exposure time.
Edit | Watch | Print version | History: r2 < r1 | Backlinks | Raw View | More topic actions

Physics WebpagesRHUL WebpagesCampus Connect • Royal Holloway, University of London, Egham, Surrey TW20 0EX; Tel/Fax +44 (0)1784 434455/437520

Topic revision: r2 - 14 Oct 2016 - AnishaVadher

 Home Public Web P P P P P View Edit Account
Copyright © 2008-2022 by the contributing authors. All material on this collaboration platform is the property of the contributing authors.
Ideas, requests, problems regarding RHUL Physics Department TWiki? Send feedback