Changeset 9462 for trunk/MagicSoft/Mars/melectronics/MAvalanchePhotoDiode.cc

Timestamp:

06/20/09 10:14:33 (15 years ago)

Author:

tbretz

Message:

*** empty log message ***

File:

• trunk/MagicSoft/Mars/melectronics/MAvalanchePhotoDiode.cc (modified) (6 diffs)

trunk/MagicSoft/Mars/melectronics/MAvalanchePhotoDiode.cc

@@ -77 +77 @@
 APD::APD(Int_t n, Float_t prob, Float_t dt, Float_t rt)
     : fHist("APD", "", n, 0.5, n+0.5, n, 0.5, n+0.5),
-    fCrosstalkProb(prob), fDeadTime(dt), fRecoveryTime(rt)
+    fCrosstalkProb(prob), fDeadTime(dt), fRecoveryTime(rt), fTime(-1)
 {
     fHist.SetDirectory(0);
+}
+
+// --------------------------------------------------------------------------
+//
+// This is the time the cell needs after a hit until less than threshold
+// (0.001 == one permille) of the signal is lost.
+//
+// If all cells of a G-APD have fired simultaneously and they are fired
+// once more after the relaxation time (with the defaultthreshold of 0.001)
+// the chip will show a signal which is one permille too small.
+//
+Float_t APD::GetRelaxationTime(Float_t threshold) const
+{
+    return fDeadTime-TMath::Log(threshold)*fRecoveryTime;
 }
 
@@ -197 +211 @@
 // The default time is 0.
 //
+// If you want t w.r.t. fTime use HitRandomCellRelative istead.
+//
 Float_t APD::HitRandomCell(Float_t t)
 {
@@ -219 +235 @@
 // If deadtime and recovery time are 0 then t-1 is set.
 //
+// Sets fTime to t
+//
 // The default time is 0.
 //
@@ -231 +249 @@
 
     fHist.SetEntries(1);
+
+    fTime = t;
 }
 
@@ -238 +258 @@
 // by calling HitCellImp with time t-gRandom->Exp(n/rate) with n being
 // the total number of cells.
+//
+// Sets fTime to t
+//
 // The default time is 0.
 //
@@ -253 +276 @@
     for (int x=1; x<=nx; x++)
         for (int y=1; y<=ny; y++)
-        {
             HitCellImp(x, y, t-MMath::RndmExp(f));
-        }
+
+    fTime = t;
+}
+
+// --------------------------------------------------------------------------
+//
+// Evolve the chip from fTime to fTime+dt if it with a given frequency
+// freq. Returns the total signal "recorded".
+//
+// fTime is set to the fTime+dt
+//
+// If you want to evolve over a default relaxation time (relax the chip
+// from a signal) use Relax instead.
+//
+Float_t APD::Evolve(Double_t freq, Double_t dt)
+{
+    const Double_t avglen = 1./freq;
+
+    const Double_t end  = fTime+dt;
+
+    Float_t hits = 0;
+
+    Double_t time = fTime;
+    while (1)
+    {
+        time += MMath::RndmExp(avglen);
+        if (time>end)
+            break;
+
+        hits += HitRandomCell(time);
+    }
+
+    fTime = end;
+
+    return hits;
 }