Changeset 5993


Ignore:
Timestamp:
01/25/05 14:25:03 (20 years ago)
Author:
gaug
Message:
*** empty log message ***
Location:
trunk/MagicSoft/TDAS-Extractor
Files:
3 edited

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  • trunk/MagicSoft/TDAS-Extractor/Algorithms.tex

    r5944 r5993  
    467467\end{equation}
    468468
    469 For the MAGIC signals, as implemented in the MC simulations, a pedestal RMS of a single FADC slice of 4 FADC counts introduces an error in the reconstructed signal and time of:
    470 
     469For the MAGIC signals, as implemented in the MC simulations, a pedestal RMS of a single FADC slice of 4 FADC counts introduces an error in the
     470reconstructed signal and time of:
    471471
    472472\begin{equation}\label{of_noise}
    … …  
    474474\end{equation}
    475475
     476\par
     477\ldots {\textit{\bf CALCULATE THESE NUMBERS FOR 6 SLICES! }} \ldots
     478\par
     479
    476480where $\Delta T_{\mathrm{FADC}} = 3.33$ ns is the sampling interval of the MAGIC FADCs.
    477481
    478482
    479 For an IACT there are two types of background noise. On the one hand there is the constantly present electronics noise, on the other hand the light of the night sky introduces a sizeable background noise to the measurement of Cherenkov photons from air showers.
    480 
    481 The electronics noise is largely white, uncorrelated in time. The noise from the night sky background photons is the superposition of the detector response to single photo electrons arriving randomly distributed in time. Figure \ref{fig:noise_autocorr_AB_36038_TDAS} shows the noise autocorrelation matrix for an open camera. The large noise autocorrelation in time of the current FADC system is due to the pulse shaping with a shaping constant of 6 ns.
    482 
    483 In general the amplitude and timing weights, $\boldsymbol{w}_{\text{amp}}$ and $\boldsymbol{w}_{\text{time}}$, depend on the pulse shape, the derivative of the pulse shape and the noise autocorrelation. In the high gain samples the correlated night sky background noise dominates over the white electronics noise. Thus different noise levels just cause the noise autocorrelation matrix $\boldsymbol{B}$ to change by a factor, which cancels out in the weights calculation. Thus in the high gain the weights are to a very good approximation independent of the night sky background noise level.
     483For an IACT there are two types of background noise. On the one hand, there is the constantly present electronics noise,
     484on the other hand, the light of the night sky introduces a sizeable background noise to the measurement of Cherenkov photons from air showers.
     485
     486The electronics noise is largely white, uncorrelated in time. The noise from the night sky background photons is the superposition of the
     487detector response to single photo electrons following a Poisson distribution in time. Figure \ref{fig:noise_autocorr_AB_36038_TDAS} shows the noise
     488autocorrelation matrix for an open camera. The large noise autocorrelation in time of the current FADC system is due to the pulse shaping with a
     489shaping constant of 6 ns.
     490
     491In general, the amplitude and time weights, $\boldsymbol{w}_{\text{amp}}$ and $\boldsymbol{w}_{\text{time}}$, depend on the pulse shape, the
     492derivative of the pulse shape and the noise autocorrelation. In the high gain samples the correlated night sky background noise dominates over
     493the white electronics noise. Thus different noise levels just cause the noise autocorrelation matrix $\boldsymbol{B}$ to change by a same factor,
     494which cancels out in the weights calculation. Thus in the high gain the weights are to a very good approximation independent of the night
     495sky background noise level.
    484496
    485497Contrary to that in the low gain samples ... .
     498\ldots
     499\ldots {\textit{\bf SITUATION FOR LOW-GAIN SAMPLES! }} \ldots
     500\par
    486501
    487502
    … …  
    497512
    498513Using the average reconstructed pulpo pulse shape, as shown in figure \ref{fig:pulpo_shape_low}, and the
    499 reconstructed noise autocorrelation matrix from a pedestal run with random triggers, the digital filter
     514reconstructed noise autocorrelation matrix from a pedestal run
     515
     516\par
     517\ldots {\textit{\bf WHICH RUN (RUN NUMBER, WHICH NSB?, WHICH PIXELS ??}} \ldots
     518\par
     519
     520with random triggers, the digital filter
    500521weights are computed. Figures \ref{fig:w_time_MC_input_TDAS} and \ref{fig:w_amp_MC_input_TDAS} show the
    501522parameterization of the amplitude and timing weights for the MC pulse shape as a function of the ...
    … …  
    509530\includegraphics[totalheight=7cm]{w_time_MC_input_TDAS.eps}
    510531\end{center}
    511 \caption[Time weights.]{Time weights $w_{\mathrm{time}}(t_0) \ldots w_{\mathrm{time}}(t_5)$ for a window size of 6 FADC slices for the pulse shape used in the MC simulations. The first weight $w_{\mathrm{time}}(t_0)$ is plotted as a function of the relative time $t_{\text{rel}}$ the trigger and the FADC clock in the range $[-0.5;0.5[ \ T_{\text{ADC}}$, the second weight in the range $[0.5;1.5[ \ T_{\text{ADC}}$ and so on. A binning resolution of $0.1  T_{\text{ADC}}$ has been chosen.} \label{fig:w_time_MC_input_TDAS}
     532\caption[Time weights.]{Time weights $w_{\mathrm{time}}(t_0) \ldots w_{\mathrm{time}}(t_5)$ for a window size of 6 FADC slices for the pulse shape
     533used in the MC simulations. The first weight $w_{\mathrm{time}}(t_0)$ is plotted as a function of the relative time $t_{\text{rel}}$ the trigger and the
     534FADC clock in the range $[-0.5,0.5[ \ T_{\text{ADC}}$, the second weight in the range $[0.5,1.5[ \ T_{\text{ADC}}$ and so on. A binning resolution
     535of $0.1  T_{\text{ADC}}$ has been chosen.} \label{fig:w_time_MC_input_TDAS}
    512536\end{figure}
    513537
    … …  
    516540\includegraphics[totalheight=7cm]{w_amp_MC_input_TDAS.eps}
    517541\end{center}
    518 \caption[Amplitude weights.]{Amplitude weights $w_{\mathrm{amp}}(t_0) \ldots w_{\mathrm{amp}}(t_5)$ for a window size of 6 FADC slices for the pulse shape used in the MC simulations. The first weight $w_{\mathrm{amp}}(t_0)$ is plotted as a function of the relative time $t_{\text{rel}}$ the trigger and the FADC clock in the range $[-0.5;0.5[ \ T_{\text{ADC}}$, the second weight in the range $[0.5;1.5[ \ T_{\text{ADC}}$ and so on. A binning resolution of $0.1  T_{\text{ADC}}$ has been chosen.} \label{fig:w_amp_MC_input_TDAS}
     542\caption[Amplitude weights.]{Amplitude weights $w_{\mathrm{amp}}(t_0) \ldots w_{\mathrm{amp}}(t_5)$ for a window size of 6 FADC slices for the
     543pulse shape used in the MC simulations. The first weight $w_{\mathrm{amp}}(t_0)$ is plotted as a function of the relative time $t_{\text{rel}}$
     544the trigger and the FADC clock in the range $[-0.5,0.5[ \ T_{\text{ADC}}$, the second weight in the range $[0.5,1.5[ \ T_{\text{ADC}}$ and so on.
     545A binning resolution of $0.1\, T_{\text{ADC}}$ has been chosen.} \label{fig:w_amp_MC_input_TDAS}
    519546\end{figure}
    520547
    … …  
    577604
    578605
     606\ldots
     607\textit {\bf FIGURE~\ref{fig:shape_fit_TDAS} shows what???}
     608\ldots
     609
    579610Figure \ref{fig:shape_fit_TDAS} shows the FADC slices of a single MC event together with the result of a full
    580611fit of the input MC pulse shape to the simulated FADC samples together with the result of the numerical fit
    … …  
    602633\item "cosmics\_weights4.dat'' with a window size of 4 FADC slices
    603634\item "calibration\_weights\_blue.dat'' with a window size of 6 FADC slices
     635\item "calibration\_weights4\_blue.dat'' with a window size of 4 FADC slices
    604636\item "calibration\_weights\_UV.dat'' with a window size of 6 FADC slices and in the low-gain the
     637calibration weigths obtained from blue pulses\footnote{UV-pulses saturating the high-gain are not yet
     638available.}.
     639\item "calibration\_weights4\_UV.dat'' with a window size of 4 FADC slices and in the low-gain the
    605640calibration weigths obtained from blue pulses\footnote{UV-pulses saturating the high-gain are not yet
    606641available.}.
    … …  
    608643weights. This file is only used for stability tests.
    609644\item "cosmics\_weights4\_logaintest.dat'' with a window size of 4 FADC slices and swapped high-gain and low-gain
     645weights. This file is only used for stability tests.
     646\item "calibration\_weights\_UV\_logaintest.dat'' with a window size of 6 FADC slices and swapped high-gain and low-gain
     647weights. This file is only used for stability tests.
     648\item "calibration\_weights4\_UV\_logaintest.dat'' with a window size of 4 FADC slices and swapped high-gain and low-gain
     649weights. This file is only used for stability tests.
     650\item "calibration\_weights\_blue\_logaintest.dat'' with a window size of 6 FADC slices and swapped high-gain and low-gain
     651weights. This file is only used for stability tests.
     652\item "calibration\_weights4\_blue\_logaintest.dat'' with a window size of 4 FADC slices and swapped high-gain and low-gain
    610653weights. This file is only used for stability tests.
    611654\end{itemize}
    … …  
    710753\item[MExtractTimeAndChargeDigitalFilter]: with the following initialization:
    711754\resume{enumerate}
    712 \item SetWeightsFile(``cosmic\_weights6.dat'');
    713 \item SetWeightsFile(``cosmic\_weights4.dat'');
     755\item SetWeightsFile(``cosmics\_weights.dat'');
     756\item SetWeightsFile(``cosmics\_weights4.dat'');
     757\item SetWeightsFile(``calibration\_weights\_UV.dat'');
     758\item SetWeightsFile(``calibration\_weights4\_UV.dat'');
     759\item SetWeightsFile(``calibration\_weights\_blue.dat'');
     760\item SetWeightsFile(``calibration\_weights4\_blue.dat'');
    714761\item SetWeightsFile(``cosmic\_weights\_logain6.dat'');
    715762\item SetWeightsFile(``cosmic\_weights\_logain4.dat'');
    716 \item SetWeightsFile(``calibration\_weights\_UV6.dat'');
     763\item SetWeightsFile(``calibration\_weights\_UV\_logaintest.dat'');
     764\item SetWeightsFile(``calibration\_weights4\_UV\_logaintest.dat'');
     765\item SetWeightsFile(``calibration\_weights\_blue\_logaintest.dat'');
     766\item SetWeightsFile(``calibration\_weights4\_blue\_logaintest.dat'');
    717767\suspend{enumerate}
    718768\item[``Real Fit'']: (not yet implemented, one try)
    … …  
    722772\end{description}
    723773
    724 Note that the extractors \#30, \#31 are used only to test the stability of the extraction against
     774Note that the extractors \#34 through \#39 are used only to test the stability of the extraction against
    725775changes in the pulse-shape.
    726776

  • trunk/MagicSoft/TDAS-Extractor/Changelog

    r5882 r5993  
    1919
    2020                                                 -*-*- END OF LINE -*-*-
     21
     222004/01/26: Markus Gaug
     23  * Algorithms.tex: text updated and new figures
     24
    2125
    22262004/01/18: Markus Gaug

  • trunk/MagicSoft/TDAS-Extractor/Pedestal.tex

    r5890 r5993  
    359359
    360360
    361 
    362 \vspace{1cm}
    363 \ldots{\it More test plots can be found under:
    364 http://magic.ifae.es/$\sim$markus/ExtractorPedestals/ }
    365 \vspace{1cm}
    366 
    367361%%% Local Variables:
    368362%%% mode: latex
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