Index: /trunk/ICRC_01/mccontrib.tex
===================================================================
--- /trunk/ICRC_01/mccontrib.tex	(revision 816)
+++ /trunk/ICRC_01/mccontrib.tex	(revision 817)
@@ -273,22 +273,25 @@
 digital output. 
 
-The first-level-trigger is looking in the digital output of the 
-271 pixels of the trigger system for next neighbor (NN) conditions.  
-The adjustable settings on the first-level-trigger 
+The first-level-trigger checks in the digital output of the 
+271 pixels of the trigger system for next neighbor (NN) 
+conditions.  
+The adjustable settings of the first-level-trigger 
 are the mulitiplicity, the topology and the minimum required 
 overlapping time. 
 
-
-The MC data produced are used to calculate some important
-parameter of the MAGIC telescope on the level of the 
-trigger system. 
-
-The second-level-trigger of the MAGIC telescope will be a 
-pattern-recognition method. This part is still in the design 
-phase. All results presented here are based on studies of the
-first-level-trigger.
+The second-level-trigger of the MAGIC telescope will be based 
+on a pattern-recognition method. 
+This part is still in the design phase. 
+All results presented here are based on studies of the
+first-level-trigger. It not mentioned somewhere else, 
+the MC data are produced with "standard"
+values (discriminator threshold = 4 mV, gate length = 6 nsec, 
+multiplicity = 4, topology of NN = {\sl closed package}). 
+
 
  
 \subsubsection{Collection area}
+
+
 
 The trigger collection area is defined as the integral 
@@ -296,8 +299,11 @@
   A(E,\Theta)  = \int_{F}{ T(E,\Theta,F) dF}
 \end{equation} 
-where T is the trigger probablity. F is perpendicular to 
-the shower axis. The results for different zenith angle $\Theta$ and
+where T is the trigger probablity. F is a plane perpendicular
+ to the shower axis. 
+The results for different zenith angle $\Theta$ and
 for different discriminator thresholds are shown in figure
 \ref{fig_collarea}.
+At low energies ($ E < 100 ~\mathrm{GeV}$), the collection area
+decreases with increasing zenith angle , and it decreases with 
 %
 %
@@ -314,7 +320,5 @@
 %
 %
-As bigger the zenith angle the smaller becomes the collection area 
-for lower energies. As bigger the discriminator threshold is set, as
-lower is the trigger collection area for low energies. 
+increasing diskriminator threshold. 
  
 
@@ -322,24 +326,25 @@
 
 The threshold of the MAGIC telesope is defined as the peak 
-in the $dN/dE$ distribution. For all different trigger settings
+in the $dN/dE$ distribution for triggered showers. 
+For all different trigger settings
 this value is determined. The energy threshold could 
-depend among other variables on the Background simulated conditions, 
+depend among other variables on the background conditions, 
 the threshold of the trigger discriminator and the zenith angle. We 
-check the influence of the three above-mentioned variables.
+check the influence of these three variables.
 
 For both, gammas and protons, some different background conditions 
 have been simulated (without any background light, diffuse light, 
-and light from Crab Nebula field of view). The results pointed out 
-that there is not any variation of the energy threshold inside our 
-error, which is few GeV, in determining the maximum. It is 
-worth to remember that this is based only in first level trigger. 
-Most likely there will be some effects when one enters the second 
+and light from Crab Nebula field of view). 
+No significant variation of the energy threshold is observed. 
+It should be stressed that this is based only on first level 
+triggers. 
+Most likely some effects will be seen after the second 
 level trigger and the shower reconstruction.
 
-Magic will do observations in a large range of zenith angles, 
-therefore is worth to study the energy threshold as function of 
-the zenith angle. In figure \ref{fig_enerthres}, it is shown for 0, 5 
-and 10 degrees. Even though larger statistic is needed, the energy 
-threshold increases slowly with the zenith angle.
+MAGIC will do observations in a large range of zenith angles, 
+therefore it is worth studying the energy threshold as function of 
+the zenith angle (see figure \ref{fig_enerthres}). 
+Even though larger statistic is needed, the energy 
+threshold increases slowly with the zenith angle, as expected.
 \begin{figure}[hb]
  \vspace*{2.0mm} % just in case for shifting the figure slightly down
@@ -353,12 +358,14 @@
 photons in the camera plane are needed to trigger the Telescope. 
 And it helps the low energy showers to fulfil the required trigger 
-conditions. In figure  \ref{fig_enerthres} one can see that the threshold 
-energy decreases  while lowering the discriminator. It is 29 GeV for 3 mV 
-and 105 GeV  for 7 mV. Since one of the aims of the Telescope is lowering as 
-much as possible the energy threshold, a low discriminator value is 
-preferred. But for 3 mV the expected rate due to protons increases a 
+conditions. 
+In figure  \ref{fig_enerthres} one can see that the threshold 
+energy decreases when lowering the discriminator. 
+It is 29 GeV for 3 mV and 105 GeV  for 7 mV. 
+Since we are aiming for a low energy threshold, 
+a low discriminator value is  preferred. 
+However, for 3 mV the expected rate due to protons increases a 
 lot (see section ~\ref{sec-rates}), while it keeps under control at 4 mV. 
-Therefore, the threshold of the discriminator would be kept above 
-4 mV, which yields a energy threshold of 45 GeV.
+Therefore, the threshold of the discriminator would be kept around  
+4 mV, which yields an energy threshold of 45 GeV.
 
 \subsubsection{Expected rates}\label{sec-rates}