geant4DetectorConstruction

geant detector construction

1. 几何旋转符合左手法则及RotationMatrix的使用
   经过验证geant4中的rotate符合左手法则

G4RotationMatrix *rot=new G4RotationMatrix;
rot->rotateX(90*degree);
rot->rotateY(90*degree);
rot->rotateZ(90*degree);

注意，再次对rot重复赋值无效，如对上述代码再作如下操作rot->rotateX(180*degree),该操作将无效，不会改变之前的rot；
那么，要对rot再次赋值该怎么办呢？如下：只需在再次赋值前加rot =new G4RotationMatrix即可；

  G4RotationMatrix* rotationMatrix_X = new G4RotationMatrix;

  for(G4int x_col_num = 0; x_col_num <=NBD_colNb; x_col_num++){
    if(x_col_num==0){  // the center colume
      NBDx = NBDx0;
      for(G4int y_row_num = 0; y_row_num <=NBD_rowNb; y_row_num++ ){
index// NBDx = NBDx0;
indexNBDy = NBDy0+R*sin(y_row_num*theta);
indexNBDz = NBDz0+R*(1-cos(y_row_num*theta));

indexif(y_row_num==0){
index  // center position
index  rotationMatrix_X = new G4RotationMatrix;
index  rotationMatrix_X->rotateX(y_row_num*theta);

index  new G4PVPlacement(rotationMatrix_X,                      //no rotation
indexindexindex    G4ThreeVector(NBDx,NBDy,NBDz),       //at (0,0,0)
indexindexindex    logicAssembleNBD,                    //its logical volume
indexindexindex    "AssembleNBD",         //its name
indexindexindex    expHall_logV,          //its mother  volume
indexindexindex    false,                 //no boolean operation
indexindexindex    0,                     //copy number
indexindexindex    true);                    //overlaps checking    
index}
indexelse{
index  //+y++
index  rotationMatrix_X = new G4RotationMatrix;
index  rotationMatrix_X->rotateX(-y_row_num*theta);

index  new G4PVPlacement(rotationMatrix_X,                      //no rotation
indexindexindex    G4ThreeVector(NBDx,NBDy,NBDz),       //at (0,0,0)
indexindexindex    logicAssembleNBD,                    //its logical volume
indexindexindex    "AssembleNBD",         //its name
indexindexindex    expHall_logV,          //its mother  volume
indexindexindex    false,                 //no boolean operation
indexindexindex    0,                     //copy number
indexindexindex    true);               // overlaps checking 
index  //-y++
index  rotationMatrix_X = new G4RotationMatrix;
index  rotationMatrix_X->rotateX(y_row_num*theta);
index  new G4PVPlacement(rotationMatrix_X,                      //no rotation
indexindexindex    G4ThreeVector(NBDx,-NBDy,NBDz),       //at (0,0,0)
indexindexindex    logicAssembleNBD,                    //its logical volume
indexindexindex    "AssembleNBD",         //its name
indexindexindex    expHall_logV,          //its mother  volume
indexindexindex    false,                 //no boolean operation
indexindexindex    0,                     //copy number
indexindexindex    true);               // overlaps checking    
index}
      }
...

2. G4VParameterisation()的使用

• ComputeTransformation defines where one of the copies is placed
• ComputeDimensions defines the size of one copy, and a constructor that initializes any member variables that are required.

G4VParameterisation的具体应用可参看Basics/B2/B2b