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Timestamp:
02/21/05 15:59:39 (20 years ago)
Author:
hbartko
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trunk/MagicSoft/TDAS-Extractor
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4 edited

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

    r6562 r6648  
    2424\end{center}
    2525\caption[Current MAGIC read-out scheme.]{Current MAGIC read-out scheme: the analog PMT signals are
    26 transferred via an analog optical link to the counting house where after the trigger decision the signals
    27 are digitized by using a 300 MHz FADCs system and written to the hard disk of a DAQ PC.}
     26transferred via an analog optical link to the counting house -- where after the trigger decision -- the signals
     27are digitized by a 300 MHz FADCs system and written to the hard disk of a DAQ PC.}
    2828\label{fig:MAGIC_read-out_scheme}
    2929\end{figure}
     
    3434
    3535
    36 In order to sample this pulse shape with the used 300 MSamples/s FADC system, the pulse is shaped to a
    37 FWHM greater than 6\,ns
    38 (the original pulse is folded with a stretching function of 6ns). Because the MAGIC FADCs have a
     36In order to sample this pulse shape with the 300 MSamples/s FADC system, the original pulse is folded with a stretching function of 6ns leading to a FWHM  greater than 6\,ns. Because the MAGIC FADCs have a
    3937resolution of 8 bit only, the signals are split into two branches with gains differing by a factor 10.
    4038One branch is delayed by 55\,ns and then both branches are multiplexed and consecutively read-out by one FADC.
    41 Figure~\ref{fig:pulpo_shape_high} shows a typical average of identical input signals. A more detailed overview about the MAGIC read-out and DAQ system is given in \cite{Magic-DAQ}.
     39Figure~\ref{fig:pulpo_shape_high} shows a typical average of identical signals. A more detailed overview about the MAGIC read-out and DAQ system is given in \cite{Magic-DAQ}.
    4240% The maximum sustained trigger rate could be 1 kHz. The FADCs feature a FIFO memory which allows a significantly higher short-time rate.
    4341% Obviously by doing this, more LONS is integrated and thus the performance of the telescope on the analysis level is degraded.
  • trunk/MagicSoft/TDAS-Extractor/MonteCarlo.tex

    r6646 r6648  
    255255\clearpage
    256256
    257 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%5
     257%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
     258
     259\subsection{Arrival Times \label{sec:mc:times}}
     260
     261Like in the case of the charge resolution, we calculated the RMS of the distribution of the deviation of the
     262reconstructed arrival time with respect to the simulated time:
     263
     264\begin{equation}
     265\Delta T_{\mathrm{MC}} \approx RMS(\widehat{T}_{rec} - T_{sim})
     266\end{equation}
     267
     268where $\widehat{T}_{rec}$ is the reconstructed arrival time and $T_{sim}$ the simulated one.
     269\par
     270
     271
     272
     273\begin{figure}[htp]%%[t!]
     274\centering
     275  \includegraphics[width=0.49\linewidth]{TimeAndChargePlots/TDAS_TimeRes_SlidW_NoNoise_HiGain.eps}
     276\vspace{\floatsep}
     277  \includegraphics[width=0.49\linewidth]{TimeAndChargePlots/TDAS_TimeRes_SlidW_WithNoise_HiGain.eps}
     278\vspace{\floatsep}
     279  \includegraphics[width=0.49\linewidth]{TimeAndChargePlots/TDAS_TimeRes_SlidW_NoNoise_LoGain.eps}
     280\vspace{\floatsep}
     281  \includegraphics[width=0.49\linewidth]{TimeAndChargePlots/TDAS_TimeRes_SlidW_WithNoise_LoGain.eps}
     282\caption[Time Resolution Sliding Windows]{The measured time resolution (RMS of extracted time minus simulated time)
     283versus number of photoelectrons,
     284for sliding window extractors in different window sizes. The top plots show the high-gain and the bottom ones
     285low-gain regions. Left: without noise, right: with simulated noise.}
     286\label{fig:mc:TimeRes_SlidW}
     287\end{figure}
     288
     289\begin{figure}[htp]
     290\centering
     291  \includegraphics[width=0.49\linewidth]{TimeAndChargePlots/TDAS_TimeRes_DFSpline_NoNoise_HiGain.eps}
     292\vspace{\floatsep}
     293  \includegraphics[width=0.49\linewidth]{TimeAndChargePlots/TDAS_TimeRes_DFSpline_WithNoise_HiGain.eps}
     294\vspace{\floatsep}
     295  \includegraphics[width=0.49\linewidth]{TimeAndChargePlots/TDAS_TimeRes_DFSpline_NoNoise_LoGain.eps}
     296\vspace{\floatsep}
     297  \includegraphics[width=0.49\linewidth]{TimeAndChargePlots/TDAS_TimeRes_DFSpline_WithNoise_LoGain.eps}
     298\caption[Time Resolution Spline and Digital Filter]{The measured time resolution (RMS of extracted time minus simulated time)
     299versus number of photoelectrons,
     300for spline and digital filter window extractors in different window sizes. The top plots show the high-gain and the bottom ones
     301low-gain regions. Left: without noise, right: with simulated noise.}
     302\label{fig:mc:TimeRes_DFSpline}
     303\end{figure}
     304
     305
     306%%% Local Variables:
     307%%% mode: latex
     308%%% TeX-master: "MAGIC_signal_reco"
     309%%% End:
     310
     311
     312
     313
     314
     315
     316
     317
     318%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
     319
     320\clearpage
    258321
    259322\subsection{Charge Signals with and without Simulated Noise \label{fig:mc:sec:mc:chargenoise}}
     323
    260324
    261325\begin{figure}[htp]
     
    282346\label{fig:mc:Bias_LoGain}
    283347\end{figure}
    284 
    285 \clearpage
    286 
    287 \subsection{Arrival Times \label{sec:mc:times}}
    288 
    289 \begin{figure}[htp]%%[t!]
    290 \centering
    291   \includegraphics[width=0.49\linewidth]{TimeAndChargePlots/TDAS_TimeRes_SlidW_NoNoise_HiGain.eps}
    292 \vspace{\floatsep}
    293   \includegraphics[width=0.49\linewidth]{TimeAndChargePlots/TDAS_TimeRes_SlidW_WithNoise_HiGain.eps}
    294 \vspace{\floatsep}
    295   \includegraphics[width=0.49\linewidth]{TimeAndChargePlots/TDAS_TimeRes_SlidW_NoNoise_LoGain.eps}
    296 \vspace{\floatsep}
    297   \includegraphics[width=0.49\linewidth]{TimeAndChargePlots/TDAS_TimeRes_SlidW_WithNoise_LoGain.eps}
    298 \caption[Time Resolution Sliding Windows]{The measured time resolution (RMS of extracted time minus simulated time)
    299 versus number of photoelectrons,
    300 for sliding window extractors in different window sizes. The top plots show the high-gain and the bottom ones
    301 low-gain regions. Left: without noise, right: with simulated noise.}
    302 \label{fig:mc:TimeRes_SlidW}
    303 \end{figure}
    304 
    305 \begin{figure}[htp]
    306 \centering
    307   \includegraphics[width=0.49\linewidth]{TimeAndChargePlots/TDAS_TimeRes_DFSpline_NoNoise_HiGain.eps}
    308 \vspace{\floatsep}
    309   \includegraphics[width=0.49\linewidth]{TimeAndChargePlots/TDAS_TimeRes_DFSpline_WithNoise_HiGain.eps}
    310 \vspace{\floatsep}
    311   \includegraphics[width=0.49\linewidth]{TimeAndChargePlots/TDAS_TimeRes_DFSpline_NoNoise_LoGain.eps}
    312 \vspace{\floatsep}
    313   \includegraphics[width=0.49\linewidth]{TimeAndChargePlots/TDAS_TimeRes_DFSpline_WithNoise_LoGain.eps}
    314 \caption[Time Resolution Spline and Digital Filter]{The measured time resolution (RMS of extracted time minus simulated time)
    315 versus number of photoelectrons,
    316 for spline and digital filter window extractors in different window sizes. The top plots show the high-gain and the bottom ones
    317 low-gain regions. Left: without noise, right: with simulated noise.}
    318 \label{fig:mc:TimeRes_DFSpline}
    319 \end{figure}
    320 
    321 
    322 %%% Local Variables:
    323 %%% mode: latex
    324 %%% TeX-master: "MAGIC_signal_reco"
    325 %%% End:
  • trunk/MagicSoft/TDAS-Extractor/Reconstruction.tex

    r6552 r6648  
    33The FADC clock is not synchronized with the trigger. Therefore, the relative position of the recorded
    44signal samples varies  from event to event with respect to the position of the signal shape.
    5 The time between the trigger decision and the first read-out sample is uniformly distributed in the range
     5The time $\Delta t$ between the trigger decision and the first read-out sample is uniformly distributed in the range
    66$t_{\text{rel}} \in [0,T_{\mathrm{FADC}}[$, where $T_{\mathrm{FADC}}=3.33$\,ns is the digitization period of the MAGIC 300\,MHz FADCs.
    7 It can be determined using the reconstructed arrival time
     7$\Delta t$ can be determined using the reconstructed arrival time
    88$t_{\mathrm{arrival}}$.%directly by a time to digital converter (TDC) or
    99
     
    3030
    3131The asynchronous sampling of the pulse shape allows to determine an average pulse shape from the recorded
    32 signal samples: The recorded signal samples can be shifted in time such that the shifted arrival times
     32signal samples: The recorded signal samples are shifted in time such that the shifted arrival times
    3333of all events are equal. In addition, the signal samples are normalized event by event using the
    3434reconstructed charge of the pulse. The accuracy of the signal shape reconstruction depends on the accuracy
    35 of the arrival time and charge reconstruction. The statistical error of the reconstructed pulse shape is well below $10^{-2}$ while the systematical error is by definition unknown at first hand.
     35of the arrival time and charge reconstruction. The relative statistical error of the reconstructed pulse shape is well below $10^{-2}$ while the systematical error is by definition unknown at first hand.
    3636
    3737
     
    8181reconstructed pulse shape for cosmics events, both have a FWHM of about 6.3 ns. As air showers due to hadronic cosmic rays trigger the telescope
    8282much more frequently than gamma showers the reconstructed pulse shape of the cosmics events corresponds mainly to hadron induced showers.
    83 The pulse shape due to electromagnetic air showers might be slightly different. The pulse shape for green calibration LED pulses is wider
     83The pulse shape due to electromagnetic air showers might be slightly different as indicated by MC simulations \cite{MC_timing_Indians}. The pulse shape for green calibration LED pulses is wider
    8484and has a pronounced tail.
    8585
  • trunk/MagicSoft/TDAS-Extractor/bibfile.bib

    r6543 r6648  
     1@ARTICLE{MC_timing_Indians,
     2   author = {{Chitnis}, V.~R. and {Bhat}, P.~N.},
     3    title = "{Possible discrimination between gamma rays and hadrons using {\v C}erenkov photon timing measurements}",
     4  journal = {Astroparticle Physics},
     5     year = 2001,
     6    month = mar,
     7   volume = 15,
     8    pages = {29-47},
     9   adsurl = {http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2001APh....15...29C&db_key=AST},
     10  adsnote = {Provided by the NASA Astrophysics Data System}
     11}
     12
     13
    114@Article{low_energy,
    215     author    = "Baixeras, C. and others",
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