Changeset 6268


Ignore:
Timestamp:
02/04/05 19:48:06 (20 years ago)
Author:
gaug
Message:
*** empty log message ***
Location:
trunk/MagicSoft/TDAS-Extractor
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1 added
1 edited

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

    r6113 r6268  
    299299possibilities are offered:
    300300
    301 \begin{enumerate}
     301\begin{description}
    302302\item[Extraction Type Amplitude:\xspace] The amplitude of the spline maximum is taken as charge signal
    303303and the (precisee) position of the maximum is returned as arrival time. This type is faster, since it
    304 performs not spline intergraion .
     304performs not spline intergraion.
    305305\item[Extraction Type Integral:\xspace] The integrated spline between maximum position minus
    306306rise time (default: 1.5 slices) and maximum position plus fall time (default: 4.5 slices)
     
    310310is slower, but yields more precise results (see section~\ref{sec:performance}) .
    311311The charge integration resolution is set to 0.1 FADC slices.
    312 \end{enumerate}
     312\end{description}
    313313
    314314The following adjustable parameters have to be set from outside:
     
    422422\begin{eqnarray}
    4234230&=&-\boldsymbol{g}^T\boldsymbol{B}^{-1}\boldsymbol{y}
    424         +\boldsymbol{g}^T\boldsymbol{B}^{-1}\boldsymbol{g}\overline{E}
    425         +\boldsymbol{g}^T\boldsymbol{B}^{-1}\dot{\boldsymbol{g}}\overline{E\tau}
     424        +\boldsymbol{g}^T\boldsymbol{B}^{-1}\boldsymbol{g}\overline{E}
     425        +\boldsymbol{g}^T\boldsymbol{B}^{-1}\dot{\boldsymbol{g}}\overline{E\tau}
    426426\\
    4274270&=&-\dot{\boldsymbol{g}}^T\boldsymbol{B}^{-1}\boldsymbol{y}
    428         +\dot{\boldsymbol{g}}^T\boldsymbol{B}^{-1}\boldsymbol{g}\overline{E}
    429         +\dot{\boldsymbol{g}}^T\boldsymbol{B}^{-1}\dot{\boldsymbol{g}}\overline{E\tau} \ .
     428        +\dot{\boldsymbol{g}}^T\boldsymbol{B}^{-1}\boldsymbol{g}\overline{E}
     429        +\dot{\boldsymbol{g}}^T\boldsymbol{B}^{-1}\dot{\boldsymbol{g}}\overline{E\tau} \ .
    430430\end{eqnarray}
    431431
     
    434434\begin{equation}
    435435\overline{E}(\tau) = \boldsymbol{w}_{\text{amp}}^T (\tau)\boldsymbol{y} \quad \mathrm{with} \quad
    436         \boldsymbol{w}_{\text{amp}}
    437         = \frac{ (\dot{\boldsymbol{g}}^T\boldsymbol{B}^{-1}\dot{\boldsymbol{g}}) \boldsymbol{B}^{-1} \boldsymbol{g} -(\boldsymbol{g}^T\boldsymbol{B}^{-1}\dot{\boldsymbol{g}})  \boldsymbol{B}^{-1} \dot{\boldsymbol{g}}} 
    438         {(\boldsymbol{g}^T \boldsymbol{B}^{-1} \boldsymbol{g})(\dot{\boldsymbol{g}}^T\boldsymbol{B}^{-1}\dot{\boldsymbol{g}}) -(\dot{\boldsymbol{g}}^T\boldsymbol{B}^{-1}\boldsymbol{g})^2 } \ ,
     436        \boldsymbol{w}_{\text{amp}}
     437        = \frac{ (\dot{\boldsymbol{g}}^T\boldsymbol{B}^{-1}\dot{\boldsymbol{g}}) \boldsymbol{B}^{-1} \boldsymbol{g} -(\boldsymbol{g}^T\boldsymbol{B}^{-1}\dot{\boldsymbol{g}})  \boldsymbol{B}^{-1} \dot{\boldsymbol{g}}} 
     438        {(\boldsymbol{g}^T \boldsymbol{B}^{-1} \boldsymbol{g})(\dot{\boldsymbol{g}}^T\boldsymbol{B}^{-1}\dot{\boldsymbol{g}}) -(\dot{\boldsymbol{g}}^T\boldsymbol{B}^{-1}\boldsymbol{g})^2 } \ ,
    439439\end{equation}
    440440
    441441\begin{equation}
    442442\overline{E\tau}(\tau)= \boldsymbol{w}_{\text{time}}^T(\tau) \boldsymbol{y} \quad
    443         \mathrm{with} \quad \boldsymbol{w}_{\text{time}}
    444         = \frac{ ({\boldsymbol{g}}^T\boldsymbol{B}^{-1}{\boldsymbol{g}}) \boldsymbol{B}^{-1} \dot{\boldsymbol{g}} -(\boldsymbol{g}^T\boldsymbol{B}^{-1}\dot{\boldsymbol{g}})  \boldsymbol{B}^{-1} {\boldsymbol{g}}} 
    445         {(\boldsymbol{g}^T \boldsymbol{B}^{-1} \boldsymbol{g})(\dot{\boldsymbol{g}}^T\boldsymbol{B}^{-1}\dot{\boldsymbol{g}}) -(\dot{\boldsymbol{g}}^T\boldsymbol{B}^{-1}\boldsymbol{g})^2 } \ .
     443        \mathrm{with} \quad \boldsymbol{w}_{\text{time}}
     444        = \frac{ ({\boldsymbol{g}}^T\boldsymbol{B}^{-1}{\boldsymbol{g}}) \boldsymbol{B}^{-1} \dot{\boldsymbol{g}} -(\boldsymbol{g}^T\boldsymbol{B}^{-1}\dot{\boldsymbol{g}})  \boldsymbol{B}^{-1} {\boldsymbol{g}}} 
     445        {(\boldsymbol{g}^T \boldsymbol{B}^{-1} \boldsymbol{g})(\dot{\boldsymbol{g}}^T\boldsymbol{B}^{-1}\dot{\boldsymbol{g}}) -(\dot{\boldsymbol{g}}^T\boldsymbol{B}^{-1}\boldsymbol{g})^2 } \ .
    446446\end{equation}
    447447
     
    462462\begin{equation}
    463463\left(\boldsymbol{V}^{-1}\right)_{i,j}
    464         =\frac{1}{2}\left(\frac{\partial^2 \chi^2(E, E\tau)}{\partial \alpha_i \partial \alpha_j} \right) \quad
    465         \text{with} \quad \alpha_i,\alpha_j \in \{E, E\tau\} \ .
     464        =\frac{1}{2}\left(\frac{\partial^2 \chi^2(E, E\tau)}{\partial \alpha_i \partial \alpha_j} \right) \quad
     465        \text{with} \quad \alpha_i,\alpha_j \in \{E, E\tau\} \ .
    466466\end{equation}
    467467
     
    470470\begin{equation}\label{of_noise}
    471471\sigma_E^2=\boldsymbol{V}_{E,E}
    472         =\frac{\dot{\boldsymbol{g}}^T\boldsymbol{B}^{-1}\dot{\boldsymbol{g}}}
    473         {(\boldsymbol{g}^T \boldsymbol{B}^{-1} \boldsymbol{g})(\dot{\boldsymbol{g}}^T\boldsymbol{B}^{-1}\dot{\boldsymbol{g}}) -(\dot{\boldsymbol{g}}^T\boldsymbol{B}^{-1}\boldsymbol{g})^2} \ .
     472        =\frac{\dot{\boldsymbol{g}}^T\boldsymbol{B}^{-1}\dot{\boldsymbol{g}}}
     473        {(\boldsymbol{g}^T \boldsymbol{B}^{-1} \boldsymbol{g})(\dot{\boldsymbol{g}}^T\boldsymbol{B}^{-1}\dot{\boldsymbol{g}}) -(\dot{\boldsymbol{g}}^T\boldsymbol{B}^{-1}\boldsymbol{g})^2} \ .
    474474\end{equation}
    475475
     
    478478\begin{equation}\label{of_noise_time}
    479479E^2 \cdot \sigma_{\tau}^2=\boldsymbol{V}_{E\tau,E\tau}
    480         =\frac{{\boldsymbol{g}}^T\boldsymbol{B}^{-1}{\boldsymbol{g}}}
    481         {(\boldsymbol{g}^T \boldsymbol{B}^{-1} \boldsymbol{g})(\dot{\boldsymbol{g}}^T\boldsymbol{B}^{-1}\dot{\boldsymbol{g}}) -(\dot{\boldsymbol{g}}^T\boldsymbol{B}^{-1}\boldsymbol{g})^2} \ .
     480        =\frac{{\boldsymbol{g}}^T\boldsymbol{B}^{-1}{\boldsymbol{g}}}
     481        {(\boldsymbol{g}^T \boldsymbol{B}^{-1} \boldsymbol{g})(\dot{\boldsymbol{g}}^T\boldsymbol{B}^{-1}\dot{\boldsymbol{g}}) -(\dot{\boldsymbol{g}}^T\boldsymbol{B}^{-1}\boldsymbol{g})^2} \ .
    482482\end{equation}
    483483
     
    496496
    497497
    498 For an IACT there are two types of background noise. On the one hand, there is the constantly present electronics noise,
    499 on the other hand, the light of the night sky introduces a sizeable background noise to the measurement of Cherenkov photons from air showers.
    500 
    501 The electronics noise is largely white, uncorrelated in time. The noise from the night sky background photons is the superposition of the
    502 detector response to single photo electrons following a Poisson distribution in time. Figure \ref{fig:noise_autocorr_AB_36038_TDAS} shows the noise
    503 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
    504 shaping constant of 6 ns.
     498For an IACT there are two types of background noise. On the one hand, there is the constantly present
     499electronics noise,
     500on the other hand, the light of the night sky introduces a sizeable background noise to the measurement of
     501Cherenkov photons from air showers.
     502
     503The electronics noise is largely white, uncorrelated in time. The noise from the night sky background photons
     504is the superposition of the
     505detector response to single photo electrons following a Poisson distribution in time.
     506Figure \ref{fig:noise_autocorr_allpixels} shows the noise
     507autocorrelation matrix for an open camera. The large noise autocorrelation in time of the current FADC
     508system is due to the pulse shaping with a shaping constant of 6 ns.
    505509
    506510In general, the amplitude and time weights, $\boldsymbol{w}_{\text{amp}}$ and $\boldsymbol{w}_{\text{time}}$, depend on the pulse shape, the
     
    521525\includegraphics[totalheight=7cm]{noise_autocorr_AB_36038_TDAS.eps}
    522526\end{center}
    523 \caption[Noise autocorrelation.]{Noise autocorrelation matrix for open camera including the noise due to night sky background fluctuations.}
    524         \label{fig:noise_autocorr_AB_36038_TDAS}
    525 \end{figure}
    526 
    527 
     527\caption[Noise autocorrelation one pixel.]{Noise autocorrelation
     528matrix for open camera including the noise due to night sky background fluctuations for one single
     529pixel.}
     530\label{fig:noise_autocorr_1pix}
     531\end{figure}
     532
     533\begin{figure}[htp]
     534\begin{center}
     535\includegraphics[totalheight=7cm]{noise_38995_smallNSB_all396.eps}
     536\includegraphics[totalheight=7cm]{noise_39258_largeNSB_all396.eps}
     537\includegraphics[totalheight=7cm]{noise_small_over_large.eps}
     538\end{center}
     539\caption[Noise autocorrelation average all pixels.]{Noise autocorrelation
     540matrix $\boldsymbol{B}$ for open camera and averaged over all pixels. The top figure shows $\boldsymbol{B}$
     541obtained with camera pointing off the galactic plane (and low night sky background fluctuations).
     542The central figure shows $\boldsymbol{B}$ with the camera pointing into the galactic plane
     543(high night sky background) and the
     544bottom plot shows the ratio between both. One can see that the entries of $\boldsymbol{B}$ do not
     545simply scale with the amount of night sky background.}
     546\label{fig:noise_autocorr_allpixels}
     547\end{figure}
    528548
    529549Using the average reconstructed pulpo pulse shape, as shown in figure \ref{fig:pulpo_shape_low}, and the
     
    549569used 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
    550570FADC 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
    551 of $0.1  T_{\text{ADC}}$ has been chosen.} \label{fig:w_time_MC_input_TDAS}
     571of $0.1\,T_{\text{ADC}}$ has been chosen.} \label{fig:w_time_MC_input_TDAS}
    552572\end{figure}
    553573
     
    581601\begin{equation}
    582602E=\sum_{i=i_0^*}^{i_0^*+n-1} w_{\mathrm{amp}}(t_i - \tau)y(t_{i+i_0^*}) \qquad
    583         E \theta=\sum_{i=i_0^*}^{i_0^*+n-1} w_{\mathrm{time}}(t_i - \tau)y(t_{i+i_0^*}) \ .
     603        E \theta=\sum_{i=i_0^*}^{i_0^*+n-1} w_{\mathrm{time}}(t_i - \tau)y(t_{i+i_0^*}) \ .
    584604\end{equation}
    585605
     
    808828%%% TeX-master: "MAGIC_signal_reco"
    809829%%% TeX-master: "MAGIC_signal_reco"
     830%%% TeX-master: "MAGIC_signal_reco.te"
    810831%%% End:
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