Preparing to make a better virtual volume for the FMD3 sub-detector -

one that doesn't overlap with T0-C and the beam pipe.

Also documented some member functions.

diff --git a/FMD/AliFMD3.cxx b/FMD/AliFMD3.cxx
index 706e1dece8960631fa5075446300c36461b28841..3fc331a74fb0deffd63a669086263f8d5d8e73de 100644 (file)
--- a/FMD/AliFMD3.cxx
+++ b/FMD/AliFMD3.cxx
@@ -15,56 +15,76 @@
 
 /* $Id$ */
 
-//////////////////////////////////////////////////////////////////////////////
+//____________________________________________________________________
 //                                                                          
 // Concrete implementation of AliFMDSubDetector 
 //
 // This implements the geometry for FMD3
 //
-//////////////////////////////////////////////////////////////////////////////
-#ifndef ALIFMD3_H
-# include "AliFMD3.h"
-#endif 
 #ifndef ROOT_TVirtualMC
 # include <TVirtualMC.h>
 #endif
+#ifndef ROOT_TCONS
+# include <TCONS.h>
+#endif
+#ifndef ROOT_TNode
+# include <TNode.h>
+#endif
+#ifndef ROOT_TList
+# include <TList.h>
+#endif
+#ifndef ALIFMD3_H
+# include "AliFMD3.h"
+#endif 
 #ifndef ALILOG_H
 # include "AliLog.h"
 #endif
 #ifndef ALIFMDRING_H
 # include "AliFMDRing.h"
 #endif 
+#include <iostream>
 
 //____________________________________________________________________
 ClassImp(AliFMD3);
 
 //____________________________________________________________________
 AliFMD3::AliFMD3() 
-  : AliFMDSubDetector(3) 
-{}
+  : AliFMDSubDetector(3), 
+    fVolumeId(0),
+    fDz(0)
+{
+  // Default constructor for the FMD3 sub-detector 
+}
+
 
 //____________________________________________________________________
 AliFMD3::~AliFMD3() 
-{}
+{
+  // Destructor - does nothing 
+}
+
 
 //____________________________________________________________________
 void 
 AliFMD3::SetupGeometry(Int_t airId, Int_t kaptionId) 
 {
+  // Setup the FMD3 sub-detector geometry 
+  // 
+  // Parameters:
+  // 
+  //     airId         Id # of the Air medium 
+  //     kaptionId     Id # of the Aluminium medium 
+  // 
   fInnerHoneyLowR  = fInner->GetLowR() + 1;
   fInnerHoneyHighR = fInner->GetHighR() + 1;
   fOuterHoneyLowR  = fOuter->GetLowR() + 1;
   fOuterHoneyHighR = fOuter->GetHighR() + 1;
 
+  CalculateDz();
   Double_t par[3];
   par[0] = fInner->GetLowR();
   par[1] = fOuterHoneyHighR;
-  par[2] = fDz = (TMath::Abs(fInnerZ - fOuterZ) 
-                 + fInner->GetSiThickness() 
-                 + fInner->GetPrintboardThickness() 
-                 + fInner->GetLegLength() 
-                 + fInner->GetModuleSpacing() 
-                 + fHoneycombThickness) / 2;
+  par[2] = fDz;
   fVolumeId = gMC->Gsvolu("FMD3", "TUBE", airId, par, 3);
 
   gMC->Matrix(fRotationId, 90, 0, 90, 90, 0, 0); 
@@ -78,6 +98,15 @@ void
 AliFMD3::Geometry(const char* mother, Int_t pbRotId, 
                  Int_t idRotId, Double_t z) 
 {
+  // Position the FMD3 sub-detector volume 
+  // 
+  // Parameters 
+  //
+  //     mother     name of the mother volume 
+  //     pbRotId    Printboard roation matrix ID 
+  //     idRotId    Identity rotation matrix ID 
+  //     z          Z position (not really used here, but passed down)
+  //
   z = fInnerZ - fDz;
   gMC->Gspos("FMD3", 1, mother, 0, 0, z, fRotationId);
   
@@ -85,6 +114,94 @@ AliFMD3::Geometry(const char* mother, Int_t pbRotId,
 }
 
   
+//____________________________________________________________________
+void 
+AliFMD3::SimpleGeometry(TList* nodes, 
+                       TNode* mother, 
+                       Int_t colour, 
+                       Double_t zMother) 
+{
+  // We need to get the equation for the line that connects the 
+  // outer circumfrences of the two rings, as  well as for the line
+  // that connects the inner curcumfrences, so that we can project to
+  // where the honey-comb actually ends. 
+  // 
+  // we have 
+  //   
+  //   y = a * x + b 
+  //   b = y - a * x;
+  // 
+  // For the outer line, we have the two equations 
+  // 
+  //    fOuterHoneyHighR = a * x1 + b;
+  //    fInnerHoneyHighR = a * x2 + b; 
+  // 
+  // where 
+  // 
+  //    x1 = (fOuterZ + fOuter->fSiThickness + fOuter->fPrintboardThickness 
+  //          + fOuter->fLegLength + fModuleSpacing) 
+  //       = fInner - fDz + fHoneycombThickness
+  //    x2 = (fInnerZ + fInner->fSiThickness + fInner->fPrintboardThickness 
+  //          + fInner->fLegLength + fModuleSpacing)
+  // 
+  // and 
+  //
+  //    a  = (fOuterHoneyHighR - fInnerHoneyHighR) / (x1 - x2)
+  //    
+  // 
+  CalculateDz();
+#if 1
+  Double_t x1  = (fOuterZ - (fOuter->GetSiThickness() 
+                            + fOuter->GetPrintboardThickness() 
+                            + fOuter->GetLegLength() 
+                            + fOuter->GetModuleSpacing()));
+  Double_t x2  = (fInnerZ - (fInner->GetSiThickness() 
+                            + fInner->GetPrintboardThickness() 
+                            + fInner->GetLegLength() 
+                            + fInner->GetModuleSpacing()));
+  Double_t ao   = 0;
+  Double_t ao1  = (fOuterHoneyHighR - fInnerHoneyHighR) / (x1 - x2);
+  Double_t ao2  = ((fOuter->GetHighR() - fInner->GetHighR()) 
+                  / (fOuterZ - fInnerZ));
+  Double_t bo   = 0;
+  if (ao2 > ao1) {
+    std::cout << "Wafer determinds the size" << std::endl;
+    ao  = ao2;
+    bo  = fInner->GetHighR() - ao * fInnerZ;
+  }
+  else {
+    ao = ao1;
+    bo = fOuterHoneyHighR - ao * x1;
+  }
+  
+  Double_t y1o = ao * (fInnerZ - 2 * fDz) + bo;
+  Double_t y2o = ao * fInnerZ + bo;
+#endif
+  // We probably need to make a PCON here. 
+  TShape* shape = new TCONS("FMD3", "FMD3", "", fDz, 
+                           fOuter->GetLowR(),  y1o, /* fOuterHoneyHighR, */
+                           fInner->GetLowR(),  y2o, /* fInnerHoneyHighR, */
+                           0, 360);
+  mother->cd();
+  zMother = fInnerZ - fDz;  
+  TNode* node = new TNode("FMD3", "FMD3", shape, 0, 0, zMother, 0);
+  node->SetVisibility(0);
+  nodes->Add(node);
+  AliFMDSubDetector::SimpleGeometry(nodes, node, colour, zMother);
+}
+
+//____________________________________________________________________
+void 
+AliFMD3::CalculateDz() 
+{
+  if (fDz > 0) return;
+  fDz = (TMath::Abs(fInnerZ - fOuterZ) 
+        + fOuter->GetSiThickness() 
+        + fOuter->GetPrintboardThickness() 
+        + fOuter->GetLegLength() 
+        + fOuter->GetModuleSpacing() 
+        + fHoneycombThickness) / 2;
+}
 
 //____________________________________________________________________
 //