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02/18/05 15:59:37 (20 years ago)
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gaug
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  • trunk/MagicSoft/TDAS-Extractor/Criteria.tex

    r6590 r6602  
    5959In 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.
    6060
    61 Note that every sliding window extractor, the digital filter and the spline extractor has a bias, especially at low or vanishing signals $S$.
     61Note that every sliding window extractor, the digital filter and the spline extractor have a bias,
     62especially at low or vanishing signals $S$, but usually a much smaller $R$ and in many cases a smaller $MSE$ than the fixed window
     63extractors.
    6264
    6365\subsection{Linearity}
    … …  
    8688and low-gain pulse is small, thus for large pulses,
    8789mis-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 at late high-gain pulses, parts of the low-gain pulse might already reach out of the recorded FADC window.
     90is relatively small and for late high-gain pulses, parts of the low-gain pulse might already reach out of the recorded FADC window.
    8991A good extractor must be
    9092stably extracting the low-gain pulse without being confused by the above points. This is especially important since the low-gain
    … …  
    109111
    110112\subsection{Applicability for Different Sampling Speeds / No Pulse Shaping.}
     113
    111114The current read-out system of the MAGIC telescope~\cite{Magic-DAQ} with 300~MSamples/s is relatively slow compared to the fast pulses of
    112115about 2\,ns FWHM of Cherenkov pulses.
    … …  
    119122\subsection{CPU Requirements}
    120123
    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.
     124Depending on the reconstruction algorithm the signal reconstruction can take a significant amount of CPU time.
     125Especially the more sophisticated signal extractors can be time consuming which search for the position of the Cherenkov signals
     126in the recorded FADC time slices and perform a fit to these samples. At any case, the extractor should not be significantly slower than
     127the reading and writing routines of the MARS software.
    122128
    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 
     129Thus, for an online-analysis a different extraction algorithm might be chosen than for the final most accurate
     130reconstruction of the signals offline.
    127131
    128132\subsection{Treatment of Calibration Pulses}
    129133
     134The calibration pulse reconstruction sets two important constraints to the signal extractor:
    130135
    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,
     138the 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 
     140non-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
     142the difference in pulse shape. This puts severe contraints on all extractors which do not integrate the whole pulse or take the pulse
     143shape into account.
     144\end{enumerate}
    142145
    143146%%% Local Variables:
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