1 | \section{Conclusions}
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2 |
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3 | In the past, many MAGIC analyses have been conducted using different signal extractors.
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4 | We developped and tested the most important signal and time extraction algorithms in the standard MAGIC software
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5 | framework MARS. Our findings are that using a right signal extractor is important since some of the investigated ones
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6 | differ considerably in quality and can severly degrade the subsequent analyses. On the other hand, we have found that
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7 | advanced signal recontruction algorithms open a new window to lower analysis energy threshold and permit to use the
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8 | time information of shower analyses.
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9 | \par
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10 | In order to give a guideline for future usage of the tested signal extractors, we consider the following
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11 | requirements to be of most importance:
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12 |
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13 | \begin{itemize}
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14 | \item The calibration (including the F-Factor method) has to run stably and yield reliable results for all pixels.
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15 | \item The extracted signal should be as linear as possible over the whole dynamic range, including especially the
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16 | low-gain range.
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17 | \item The combined resolution and bias should result in a lowest possible image cleaning threshold.
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18 | \item The extracted time should yield the best possible resolution.
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19 | \end{itemize}
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20 |
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21 | Following these requirements, we recommend to exclude in the future the following signal extraction algorithms:
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22 |
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23 | \begin{itemize}
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24 | \item All fixed window extractors using a window size of up to 6~FADC slices,
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25 | including the fixed window peak search algorithm.
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26 | \item All sliding window extractors using a window size of up to 4~FADC slices.
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27 | \item The amplitude extracting spline.
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28 | \end{itemize}
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29 |
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30 | For a conservative and stable analysis, we recommend to use (except for the December~2004 and January~2005 data):
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31 |
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32 | \begin{itemize}
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33 | \item The sliding window, using an extraction window size of 6--8~FADC slices for the high-gain and 8~FADC slices for the
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34 | low-gain channel.
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35 | \end{itemize}
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36 |
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37 | For the most demanding analyses, especially at low energies and using the timing information, we recommend:
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38 |
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39 | \begin{itemize}
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40 | \item The spline algorithm, integrating from 0.5~FADC slices before the pulse maximum to 1.5~FADC slices after the
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41 | pulse maximum and computing the position of the half-maximum at the rising edge of the pulse.
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42 | \item The digital filter fitting the pulse over 4~or 6~FADC slices in the high-gain region and 6~FADC slices in the
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43 | low-gain region.
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44 | \end{itemize}
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45 |
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46 | Unfortunately, part of our recent data, taken in December~2004 and January~2005 had a severe problem with the pulse location
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47 | within the recorded FADC slices. In the recorded samples, the low-gain pulse situated so far to the right that a part of
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48 | it has not been recorded any more. This poses severe problems to all extractors which integrate the entire low-gain pulse.
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49 | We have seen that the spline extractor and the digital filter over 4~FADC slices are still capable to reconstruct the low-gain
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50 | pulse properly for this partly corrupt data sample.
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51 |
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52 | %%% Local Variables:
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53 | %%% mode: latex
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54 | %%% TeX-master: "MAGIC_signal_reco"
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55 | %%% End:
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