Changeset 811 for trunk


Ignore:
Timestamp:
05/29/01 17:09:21 (23 years ago)
Author:
blanch
Message:
First draft for energy Threshold section.
File:
1 edited

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  • trunk/ICRC_01/mccontrib.tex

    r810 r811  
    301301The threshold of the MAGIC telesope is defined as the peak
    302302in the $dN/dE$ distribution. For all different trigger settings
    303 this value is determined.
     303this value is determined. The energy threshold could
     304depend among other variables on the Background simulated conditions,
     305the threshold of the trigger discriminator and the zenith angle. We
     306check the influence of the three above-mentioned variables.
     307
     308\begin{figure}[h]
     309 \vspace*{2.0mm} % just in case for shifting the figure slightly down
     310 \includegraphics[width=8.3cm]{enerthres.eps} % .eps for Latex,
     311                                            % pdfLatex allows .pdf, .jpg, .png and .tif
     312 \caption{Caption text}
     313 \label{fig_enerthres}
     314\end{figure}
     315
     316For both, gammas and protons, some different background conditions
     317have been simulated (without any background light, diffuse light,
     318and light from Crab Nebula field of view). The results pointed out
     319that there is not any variation of the energy threshold inside our
     320error in determining the maximum that is few GeV for gammas, It is
     321worth to remember that this is based only in first level trigger.
     322Most likely there will be some effects when one enters the second
     323level trigger and the shower reconstruction.
     324
     325Magic will do observations in a large range of zenith angles,
     326therefore is worth to studie the energy threshold as function of
     327the zenith angle. In figure three it is shown for 0, 5 and 10 degrees.
     328
     329If one lowers the threshold of the trigger discriminator, then less
     330photons in the camera plane are needed to trigger the Telescope.
     331And it helps the low energy showers to fulfil the required trigger
     332conditions. In figure 3 one can see that the threshold energy decreases
     333while lowering the discriminator. It is 25 GeV for 3 mV and 105 GeV
     334for 7 mV. Since one of the aims of the Telescope is lowering as much
     335as possible the energy threshold, a low discriminator value is
     336preferred. But for 3 mV the expected rate due to protons increases a
     337lot (see section 3.1.3), while it keeps under control at 4 mV.
     338Therefore, the threshold of the discriminator would be keep above
     3394 mV, which yields a energy threshold of 45 GeV.
    304340
    305341\subsubsection{Expected rates}
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