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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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Closer Look at the Effect of
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Peak Size
Since the square peak finder only find 4 pixel peaks, only the data for the V1 peak finder is shown below. This data consists of 29,342 peaks found from the 13 different events.
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| Mean | Error | RMS | |
|---|---|---|---|
| Shifted | 141.55 | 0.06 | 8.59 |
| Unshifted | 142.06 | 0.06 | 8.72 |
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Shapes
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Effects for 3 Pixel Peaks
Three pixel peaks are interesting peaks because they seem like they are extremely unlikely to happen, or at least less likely than what we see. To understand which shape is being discussed, the following names were chosen to represent the different possible shapes:
| Name | Description |
|---|---|
| C | Both non-max pixels are adjacent to the max pixel but not opposite each other |
| L | One non-max pixel is adjacent to the max pixel while the second is adjacent to the first so as to not form a straight line |
| I | A straight line where the middle pixel is the maxpixelmax pixel |
| Idot | A straight line where one of the end pixels is the max pixel |
| HS | (Hockey Stick) An Idot where the pixel furthest from the max pixel is shifted one pixel in either the positive or negative directions perpendicular to the original line |
| NaS | (Not a Shape) Any shape that is not described by any of the above shapes (This included peaks where no non-max pixel is adjacent to the max pixel |
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As expected, the Hockey Stick shapes peak does shift to the left. The peak is now at about 137 ADU; this is less than the peak of the entire distribution, but it is closer. And, visually, the peak appears to be thinner than before. The L shape peaks were also affected . but the result appears to be worse. Thus, cutting the Hockey Stick shapes but not cutting the L shapes would be the most beneficial.
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