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The data from experiment xcs06016 and run 37 were used in this analysis. Only sparse events were used so multiple photon peaks or pixels shared by multiple photons are extremely rare; events with less than 3000 peaks found by each peak finder were used. A total of 13 events were used. The purpose of these analyses is to determine which (if any) of the following methods discussed below have an appreciable effect on the RMS of the distribution of the energy. Through the entirety of this study, the parameters were held constant unless otherwise stated. For the square peak finder, an initial threshold of 15 10 ADU was used. For the V1 and V4 algorithms, a rank of 1, a low threshold of 10 and a high threshold of 30 were used. The other parameters were set so as to not any noise subtraction in the calculation of the peak energies. The maximum peak size was set at 4 pixels since a single photon peak of greater than 4 pixels is unreasonable.

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Below the first plot shows the energy distribution of the V1 and V4 algorithms while the second shows them overlapped. Visually, there appears to be very little difference between the two algorithms. This isn't too surprising since, when looking at single photons with a rank of 1, the cases which the V4 algorithm ignores would be very rare. The V1 data is the same as before, while a Gaussian fit to the V4 curve has a mean of 140.67 ± 0.06 with an RMS of 9.01. In the case shown below, the V4 algorithm was passed the parameters of r = 3 and dr = 3 which gives a large ring for noise. The opposite, no ring of noise, was tried but gave an even larger RMS.

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The Effect of Peak Size

Since the square peak finder only find 4 pixel peaks, only the data for the V1  and V4 peak finder is shown below.  This data consists of 29,342 peaks found from the 13 different events.

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