- Timestamp:
- 01/05/05 12:44:21 (20 years ago)
- Location:
- trunk/MagicSoft/TDAS-Extractor
- Files:
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- 2 edited
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trunk/MagicSoft/TDAS-Extractor/Changelog
r5696 r5699 19 19 20 20 -*-*- END OF LINE -*-*- 21 22 2004/01/05: Markus Gaug 23 * Introduction.tex: Some changes in style 21 24 22 25 2005/01/04: Hendrik Bartko -
trunk/MagicSoft/TDAS-Extractor/Introduction.tex
r5623 r5699 5 5 \end{itemize} 6 6 7 The MAGIC read-out scheme, including the PMT camera, the analog-optical link, the majority trigger logic and FADCs, is schematically shown in figure \ref{fig:MAGIC_read-out_scheme}. The used PMTs provide a very fast response to the input light signal. The response of the PMTs to sub-ns input light pulses shows a FWHM of 1.0 - 1.2 ns and rise and fall times of 600 and 700 ps correspondingly \cite{Magic-PMT}. By modulating VCSEL type laser diodes in amplitude the ultra fast analogue signals from the PMTs are transferred via 162m long, 50/125 $\mu$m diameter optical fibers to the counting house \cite{MAGIC-analog-link-2}. After transforming the light back to an electrical signal, the original PMT pulse has a FWHM of about 2.2 ns and rise and fall times of about 1ns. % was 2.2 ns 7 Figure~\ref{fig:MAGIC_read-out_scheme} shows a sketch of the MAGIC read-out scheme, including the PMT camera, 8 the analog-optical link, the majority trigger logic and 9 FADCs. The used PMTs provide a very fast 10 response to the input light signal. The response of the PMTs to sub-ns input light pulses shows a FWHM of 11 1.0 - 1.2 ns and rise and fall times of 600 and 700 ps correspondingly \cite{Magic-PMT}. By modulating VCSEL 12 type laser diodes in amplitude, the fast analogue signals from the PMTs are transferred via 162\,m long, 13 50/125\,$\mu$m diameter optical fibers to the counting house \cite{MAGIC-analog-link-2}. After transforming the 14 light back to an electrical signal, the original PMT pulse has a FWHM of about 2.2 ns and rise and fall 15 times of about 1\,ns. % was 2.2 ns 8 16 9 17 %an analog optical link \ci … … 15 23 \includegraphics[width=\textwidth]{Magic_readout_scheme1.eps} 16 24 \end{center} 17 \caption[Current MAGIC read-out scheme.]{Current MAGIC read-out scheme: the analog PMT signals are transferred via an analog optical link to the counting house where after the trigger decision the signals are digitized by using a 300 MHz FADCs system and written to the hard disk of a DAQ PC.} \label{fig:MAGIC_read-out_scheme} 25 \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.} 28 \label{fig:MAGIC_read-out_scheme} 18 29 \end{figure} 19 30 … … 23 34 24 35 25 In order to sample this pulse shape with the used 300 MSamples/s FADC system, the pulse is stretched to a FWHM $>6$ ns (the original pulse is folded with a stretching function of 6ns). Because the MAGIC FADCs have a resolution of 8 bit only, the signals are split into two branches with different gains by a factor of 10. One branch is delayed by 50 ns and then both branches are multiplexed and consecutively read-out by one FADC. % The maximum sustained trigger rate could be 1 kHz. The FADCs feature a FIFO memory which allows a significantly higher short-time rate. 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 39 resolution of 8 bit only, the signals are split into two branches with gains differing by a factor 10. 40 One 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. 42 % The maximum sustained trigger rate could be 1 kHz. The FADCs feature a FIFO memory which allows a significantly higher short-time rate. 26 43 % Obviously by doing this, more LONS is integrated and thus the performance of the telescope on the analysis level is degraded. 44 45 \par 46 47 \ldots {\textit{STILL MISSING:} \ldots 48 \begin{itemize} 49 \item DAQ jumps 50 \item clock noise 51 \end{itemize} 52 53 } \ldots 27 54 28 55
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