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trunk/MagicSoft/TDAS-Extractor/Criteria.tex (modified) (4 diffs)
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trunk/MagicSoft/TDAS-Extractor/Criteria.tex
r6590 r6602 59 59 In the case of MAGIC the background fluctuations are due to electronics noise and the PMT response to LONS. The signals from the latter background are not distinguishable from the Cherenkov signals. Thus each algorithm which searches for the signals inside the recorded FADC time slices will have a bias. In case of no Cherenkov signal it will reconstruct the largest noise pulse. 60 60 61 Note that every sliding window extractor, the digital filter and the spline extractor has a bias, especially at low or vanishing signals $S$. 61 Note that every sliding window extractor, the digital filter and the spline extractor have a bias, 62 especially at low or vanishing signals $S$, but usually a much smaller $R$ and in many cases a smaller $MSE$ than the fixed window 63 extractors. 62 64 63 65 \subsection{Linearity} … … 86 88 and low-gain pulse is small, thus for large pulses, 87 89 mis-interpretations between the tails of the high-gain pulse and the low-gain pulse might occur. Moreover, the total recorded time window 88 is relatively small and atlate high-gain pulses, parts of the low-gain pulse might already reach out of the recorded FADC window.90 is relatively small and for late high-gain pulses, parts of the low-gain pulse might already reach out of the recorded FADC window. 89 91 A good extractor must be 90 92 stably extracting the low-gain pulse without being confused by the above points. This is especially important since the low-gain … … 109 111 110 112 \subsection{Applicability for Different Sampling Speeds / No Pulse Shaping.} 113 111 114 The current read-out system of the MAGIC telescope~\cite{Magic-DAQ} with 300~MSamples/s is relatively slow compared to the fast pulses of 112 115 about 2\,ns FWHM of Cherenkov pulses. … … 119 122 \subsection{CPU Requirements} 120 123 121 Depending on the reconstruction algorithm the signal reconstruction can take a significant amount of CPU time. Especially the more sophisticated signal extractors which search for the position of the Cherenkov signals in the recorded FADC time slices and perform a fit to these samples can be time consuming. 124 Depending on the reconstruction algorithm the signal reconstruction can take a significant amount of CPU time. 125 Especially the more sophisticated signal extractors can be time consuming which search for the position of the Cherenkov signals 126 in the recorded FADC time slices and perform a fit to these samples. At any case, the extractor should not be significantly slower than 127 the reading and writing routines of the MARS software. 122 128 123 Thus for an online-analysis a different extraction algorithm might be chosen than for the final most accurate reconstruction of the signals offline. 124 125 126 129 Thus, for an online-analysis a different extraction algorithm might be chosen than for the final most accurate 130 reconstruction of the signals offline. 127 131 128 132 \subsection{Treatment of Calibration Pulses} 129 133 134 The calibration pulse reconstruction sets two important constraints to the signal extractor: 130 135 131 \subsection{Pulpo Pulses} 132 133 \subsection{Cosmics Data?} 134 The results of this subsection are based on the following runs taken 135 on the 21st of September 2004. 136 \begin{itemize} 137 \item{Run 39000}: OffCrab11 at 19.1 degrees zenith angle and 106.2 138 azimuth. 139 \item{Run 39182}: CrabNebula at 19.0 degrees zenith angle and 106.0 azimuth. 140 \end{itemize} 141 136 \begin{enumerate} 137 \item As the standard calibration uses the F-Factor method in order to reconstruct the number of impinging photo-electrons, 138 the resolution of the extractor must be constant for different signal heights, especially between the case: $S=0$ and 139 $S = 40\pm 7$~photo-electrons which is the default intensity of the current calibration pulses. This constraint is especially 140 non-trivial for extractors searching the signal in a sliding window. 141 \item As the calibration pulses are slightly wider than the cosmics pulses, the obtained conversion factors must not be affected by 142 the difference in pulse shape. This puts severe contraints on all extractors which do not integrate the whole pulse or take the pulse 143 shape into account. 144 \end{enumerate} 142 145 143 146 %%% Local Variables:
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