Beam_Pipe.cc

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//! \file
//!
//! Source file for Beam_Pipe class.
//!
//! The Beam_Pipe class is used to build the beamline for the OLYMPUS
//! detector simulation.  This file declares the Beam_Pipe class and the
//! member routines which construct the OLYMPUS beam line.
//!
//! \author D.K. Hasell
//! \version 1.0
//! \date 2010-02-27
//!
//! \ingroup detector

// *+****1****+****2****+****3****+****4****+****5****+****6****+****7****+****

// Include the Beam_Pipe header file.

#include "Beam_Pipe.h"

// Include the GEANT4 header files referenced in this file.

#include "G4VPhysicalVolume.hh"
#include "G4LogicalVolume.hh"
#include "G4PVPlacement.hh"
#include "G4VSolid.hh"
#include "G4Tubs.hh"
#include "G4Cons.hh"
#include "G4UnionSolid.hh"
#include "G4SubtractionSolid.hh"
#include "G4Material.hh"
#include "G4ThreeVector.hh"
#include "G4VisAttributes.hh"
#include "G4Colour.hh"

// Use the standard namespace.

using namespace std;

// Routines to define the OLYMPUS Beam_Pipe class.

// Constructor.

Beam_Pipe::Beam_Pipe() {}

// Destructor.

Beam_Pipe::~Beam_Pipe() {}

// Member function to build the beamline.

void Beam_Pipe::Build( G4VPhysicalVolume * World_phys ) {

   // Building the Beamline.

   cout << "Building the Beam Pipe volume.\n" << flush;

   // Declare pointers to the solid, union, and logical volumes used here.

   G4VSolid * Solid_1;
   G4VSolid * Solid_2;

   G4UnionSolid * Solid_3;
   G4UnionSolid * Solid_4;

   G4LogicalVolume * Log_1;
   G4LogicalVolume * Log_2;

   // Declare variables used for the dimensions, OD, ID, length, and Z.

   G4double OD, OD1, OD2;
   G4double ID, ID1, ID2;
   G4double L;
   G4double Z;

   G4double Deg360 = 360.0 * degree;

   // Define colours for the various materials used.

   G4Colour Gas( 0.000, 0.000, 0.000 );
   G4Colour Al(  0.663, 0.675, 0.714 );
   G4Colour SST( 0.878, 0.875, 0.859 );
 
   // Work away from the upstream face of the target chamber.

   Z = -65.0 * cm;
   
   // -------------------------------------------------------------------------

   // Dimensions for pipe connecting target chamber to flange.

   OD = 2.500 * 2.54 * cm / 2.0;
   ID = 2.250 * 2.54 * cm / 2.0;
   L  = 2.025 * 2.54 * cm / 2.0;

   // Create the volume and place it.

   Solid_1 = new G4Tubs( "BP_U1_solid", 0.0, OD, L, 0.0, Deg360 );

   Log_1 = new G4LogicalVolume( Solid_1, G4Material::GetMaterial( "Beam_gas" ),
                                "BP_U1_log", 0, 0, 0, true );
   
   Log_1->SetVisAttributes( G4VisAttributes( false, Gas ) );

   new G4PVPlacement( 0, G4ThreeVector( 0.0, 0.0, Z - L ), 
                      "BP_U1_phys", Log_1, World_phys, false, 0, true );

   // Create the tube and place it.

   Solid_2 = new G4Tubs( "BP_U2_solid", ID, OD, L, 0.0, Deg360 );

   Log_2 = new G4LogicalVolume( Solid_2, G4Material::GetMaterial( "G4_Al" ),
                                "BP_U2_log", 0, 0, 0, true );

   Log_2->SetVisAttributes( G4VisAttributes( true, Al ) );

   new G4PVPlacement( 0, G4ThreeVector(),
                      Log_2, "BP_U2_phys", Log_1, false, 0, true );

   Z -= 2.0 * L;

   // -------------------------------------------------------------------------

   // Dimensions for aluminum portion of flange.

   OD = 4.47 * 2.54 * cm / 2.0;
   ID = 2.25 * 2.54 * cm / 2.0;
   L  = 0.75 * 2.54 * cm / 2.0 * 2.0 / 3.0;

   // Create the volume and place it.

   Solid_1 = new G4Tubs( "BP_U3_solid", 0.0, OD, L, 0.0, Deg360 );

   Log_1 = new G4LogicalVolume( Solid_1, G4Material::GetMaterial( "Beam_gas" ),
                                "BP_U3_log", 0, 0, 0, true );
   
   Log_1->SetVisAttributes( G4VisAttributes( false, Gas ) );

   new G4PVPlacement( 0, G4ThreeVector( 0.0, 0.0, Z - L ), 
                      "BP_U3_phys", Log_1, World_phys, false, 0, true );

   // Create the tube and place it.

   Solid_2 = new G4Tubs( "BP_U4_solid", ID, OD, L, 0.0, Deg360 );

   Log_2 = new G4LogicalVolume( Solid_2, G4Material::GetMaterial( "G4_Al" ),
                                "BP_U4_log", 0, 0, 0, true );

   Log_2->SetVisAttributes( G4VisAttributes( true, Al ) );

   new G4PVPlacement( 0, G4ThreeVector(),
                      Log_2, "BP_U4_phys", Log_1, false, 0, true );

   Z -= 2.0 * L;

   // -------------------------------------------------------------------------

   // Dimensions for SST portion of flange.

   OD = 4.47 * 2.54 * cm / 2.0;
   ID = 2.25 * 2.54 * cm / 2.0;
   L  = 0.75 * 2.54 * cm / 2.0 * 1.0 / 3.0;

   // Create the volume and place it.

   Solid_1 = new G4Tubs( "BP_U5_solid", 0.0, OD, L, 0.0, Deg360 );

   Log_1 = new G4LogicalVolume( Solid_1, G4Material::GetMaterial( "Beam_gas" ),
                                "BP_U5_log", 0, 0, 0, true );
   
   Log_1->SetVisAttributes( G4VisAttributes( false, Gas ) );

   new G4PVPlacement( 0, G4ThreeVector( 0.0, 0.0, Z - L ), 
                      "BP_U5_phys", Log_1, World_phys, false, 0, true );

   // Create the tube and place it.

   Solid_2 = new G4Tubs( "BP_U6_solid", ID, OD, L, 0.0, Deg360 );

   Log_2 = new G4LogicalVolume( Solid_2, G4Material::GetMaterial( "SST316" ),
                                "BP_U6_log", 0, 0, 0, true );

   Log_2->SetVisAttributes( G4VisAttributes( true, SST ) );

   new G4PVPlacement( 0, G4ThreeVector(),
                      Log_2, "BP_U6_phys", Log_1, false, 0, true );

   Z -= 2.0 * L;

   // -------------------------------------------------------------------------

   // Dimensions for SST flange.

   OD = 4.47 * 2.54 * cm / 2.0;
   ID = 2.25 * 2.54 * cm / 2.0;
   L  = 0.68 * 2.54 * cm / 2.0;

   // Create the volume and place it.

   Solid_1 = new G4Tubs( "BP_U7_solid", 0.0, OD, L, 0.0, Deg360 );

   Log_1 = new G4LogicalVolume( Solid_1, G4Material::GetMaterial( "Beam_gas" ),
                                "BP_U7_log", 0, 0, 0, true );
   
   Log_1->SetVisAttributes( G4VisAttributes( false, Gas ) );

   new G4PVPlacement( 0, G4ThreeVector( 0.0, 0.0, Z - L ), 
                      "BP_U7_phys", Log_1, World_phys, false, 0, true );

   // Create the tube and place it.

   Solid_2 = new G4Tubs( "BP_U8_solid", ID, OD, L, 0.0, Deg360 );

   Log_2 = new G4LogicalVolume( Solid_2, G4Material::GetMaterial( "SST316" ),
                                "BP_U8_log", 0, 0, 0, true );

   Log_2->SetVisAttributes( G4VisAttributes( true, SST ) );

   new G4PVPlacement( 0, G4ThreeVector(),
                      Log_2, "BP_U8_phys", Log_1, false, 0, true );

   Z -= 2.0 * L;

   // -------------------------------------------------------------------------

   // Dimensions for SST beampipe.

   OD =   2.50 * 2.54 * cm / 2.0;
   ID =   2.25 * 2.54 * cm / 2.0;
   L  = 100.00 * 2.54 * cm / 2.0;

   // Create the volume and place it.

   Solid_1 = new G4Tubs( "BP_U9_solid", 0.0, OD, L, 0.0, Deg360 );

   Log_1 = new G4LogicalVolume( Solid_1, G4Material::GetMaterial( "Beam_gas" ),
                                "BP_U9_log", 0, 0, 0, true );
   
   Log_1->SetVisAttributes( G4VisAttributes( false, Gas ) );

   new G4PVPlacement( 0, G4ThreeVector( 0.0, 0.0, Z - L ), 
                      "BP_U9_phys", Log_1, World_phys, false, 0, true );

   // Create the tube and place it.

   Solid_2 = new G4Tubs( "BP_U10_solid", ID, OD, L, 0.0, Deg360 );

   Log_2 = new G4LogicalVolume( Solid_2, G4Material::GetMaterial( "SST316" ),
                                "BP_U10_log", 0, 0, 0, true );

   Log_2->SetVisAttributes( G4VisAttributes( true, SST ) );

   new G4PVPlacement( 0, G4ThreeVector(),
                      Log_2, "BP_U10_phys", Log_1, false, 0, true );

   Z -= 2.0 * L;

   // -------------------------------------------------------------------------
   // -------------------------------------------------------------------------

   // Work away from the downstream face of the target chamber.

   Z = 55.0 * cm;

   // -------------------------------------------------------------------------

   // Dimensions for pipe connecting target chamber to flange.

   OD = 2.500 * 2.54 * cm / 2.0;
   ID = 2.250 * 2.54 * cm / 2.0;
   L  = 2.025 * 2.54 * cm / 2.0;

   // Create the volume and place it.

   Solid_1 = new G4Tubs( "BP_D1_solid", 0.0, OD, L, 0.0, Deg360 );

   Log_1 = new G4LogicalVolume( Solid_1, G4Material::GetMaterial( "Beam_gas" ),
                                "BP_D1_log", 0, 0, 0, true );
   
   Log_1->SetVisAttributes( G4VisAttributes( false, Gas ) );

   new G4PVPlacement( 0, G4ThreeVector( 0.0, 0.0, Z + L ), 
                      "BP_D1_phys", Log_1, World_phys, false, 0, true );

   // Create the tube and place it.

   Solid_2 = new G4Tubs( "BP_D2_solid", ID, OD, L, 0.0, Deg360 );

   Log_2 = new G4LogicalVolume( Solid_2, G4Material::GetMaterial( "G4_Al" ),
                                "BP_D2_log", 0, 0, 0, true );

   Log_2->SetVisAttributes( G4VisAttributes( true, Al ) );

   new G4PVPlacement( 0, G4ThreeVector(),
                      Log_2, "BP_D2_phys", Log_1, false, 0, true );

   Z += 2.0 * L;

   // -------------------------------------------------------------------------

   // Dimensions for aluminum portion of flange.

   OD = 4.47 * 2.54 * cm / 2.0;
   ID = 2.25 * 2.54 * cm / 2.0;
   L  = 0.75 * 2.54 * cm / 2.0 * 2.0 / 3.0;

   // Create the volume and place it.

   Solid_1 = new G4Tubs( "BP_D3_solid", 0.0, OD, L, 0.0, Deg360 );

   Log_1 = new G4LogicalVolume( Solid_1, G4Material::GetMaterial( "Beam_gas" ),
                                "BP_D3_log", 0, 0, 0, true );
   
   Log_1->SetVisAttributes( G4VisAttributes( false, Gas ) );

   new G4PVPlacement( 0, G4ThreeVector( 0.0, 0.0, Z + L ), 
                      "BP_D3_phys", Log_1, World_phys, false, 0, true );

   // Create the tube and place it.

   Solid_2 = new G4Tubs( "BP_D4_solid", ID, OD, L, 0.0, Deg360 );

   Log_2 = new G4LogicalVolume( Solid_2, G4Material::GetMaterial( "G4_Al" ),
                                "BP_D4_log", 0, 0, 0, true );

   Log_2->SetVisAttributes( G4VisAttributes( true, Al ) );

   new G4PVPlacement( 0, G4ThreeVector(),
                      Log_2, "BP_D4_phys", Log_1, false, 0, true );

   Z += 2.0 * L;

   // -------------------------------------------------------------------------

   // Dimensions for SST portion of flange.

   OD = 4.47 * 2.54 * cm / 2.0;
   ID = 2.25 * 2.54 * cm / 2.0;
   L  = 0.75 * 2.54 * cm / 2.0 * 1.0 / 3.0;

   // Create the volume and place it.

   Solid_1 = new G4Tubs( "BP_D5_solid", 0.0, OD, L, 0.0, Deg360 );

   Log_1 = new G4LogicalVolume( Solid_1, G4Material::GetMaterial( "Beam_gas" ),
                                "BP_D5_log", 0, 0, 0, true );
   
   Log_1->SetVisAttributes( G4VisAttributes( false, Gas ) );

   new G4PVPlacement( 0, G4ThreeVector( 0.0, 0.0, Z + L ), 
                      "BP_D5_phys", Log_1, World_phys, false, 0, true );

   // Create the tube and place it.

   Solid_2 = new G4Tubs( "BP_D6_solid", ID, OD, L, 0.0, Deg360 );

   Log_2 = new G4LogicalVolume( Solid_2, G4Material::GetMaterial( "SST316" ),
                                "BP_D6_log", 0, 0, 0, true );

   Log_2->SetVisAttributes( G4VisAttributes( true, SST ) );

   new G4PVPlacement( 0, G4ThreeVector(),
                      Log_2, "BP_D6_phys", Log_1, false, 0, true );

   Z += 2.0 * L;

   // -------------------------------------------------------------------------

   // Dimensions for SST flange.

   OD = 4.470 * 2.54 * cm / 2.0;
   ID = 2.375 * 2.54 * cm / 2.0;
   L  = 0.680 * 2.54 * cm / 2.0;

   // Create the volume and place it.

   Solid_1 = new G4Tubs( "BP_D7_solid", 0.0, OD, L, 0.0, Deg360 );

   Log_1 = new G4LogicalVolume( Solid_1, G4Material::GetMaterial( "Beam_gas" ),
                                "BP_D7_log", 0, 0, 0, true );
   
   Log_1->SetVisAttributes( G4VisAttributes( false, Gas ) );

   new G4PVPlacement( 0, G4ThreeVector( 0.0, 0.0, Z + L ), 
                      "BP_D7_phys", Log_1, World_phys, false, 0, true );

   // Create the tube and place it.

   Solid_2 = new G4Tubs( "BP_D8_solid", ID, OD, L, 0.0, Deg360 );

   Log_2 = new G4LogicalVolume( Solid_2, G4Material::GetMaterial( "SST316" ),
                                "BP_D8_log", 0, 0, 0, true );

   Log_2->SetVisAttributes( G4VisAttributes( true, SST ) );

   new G4PVPlacement( 0, G4ThreeVector(),
                      Log_2, "BP_D8_phys", Log_1, false, 0, true );

   Z += 2.0 * L;

   // -------------------------------------------------------------------------

   // Dimensions for short SST pipe.

   OD = 2.500 * 2.54 * cm / 2.0;
   ID = 2.375 * 2.54 * cm / 2.0;
   L  = 8.640 * 2.54 * cm / 2.0;

   // Create the volume and place it.

   Solid_1 = new G4Tubs( "BP_D9_solid", 0.0, OD, L, 0.0, Deg360 );

   Log_1 = new G4LogicalVolume( Solid_1, G4Material::GetMaterial( "Beam_gas" ),
                                "BP_D9_log", 0, 0, 0, true );
   
   Log_1->SetVisAttributes( G4VisAttributes( false, Gas ) );

   new G4PVPlacement( 0, G4ThreeVector( 0.0, 0.0, Z + L ), 
                      "BP_D9_phys", Log_1, World_phys, false, 0, true );

   // Create the tube and place it.

   Solid_2 = new G4Tubs( "BP_D10_solid", ID, OD, L, 0.0, Deg360 );

   Log_2 = new G4LogicalVolume( Solid_2, G4Material::GetMaterial( "SST316" ),
                                "BP_D10_log", 0, 0, 0, true );

   Log_2->SetVisAttributes( G4VisAttributes( true, SST ) );

   new G4PVPlacement( 0, G4ThreeVector(),
                      Log_2, "BP_D10_phys", Log_1, false, 0, true );

   Z += 2.0 * L;

   // -------------------------------------------------------------------------

   // Dimensions for two SST flanges.

   OD = 4.470 * 2.54 * cm / 2.0;
   ID = 2.375 * 2.54 * cm / 2.0;
   L  = 0.680 * 2.54 * cm / 2.0 * 2.0;

   // Create the volume and place it.

   Solid_1 = new G4Tubs( "BP_D11_solid", 0.0, OD, L, 0.0, Deg360 );

   Log_1 = new G4LogicalVolume( Solid_1, G4Material::GetMaterial( "Beam_gas" ),
                                "BP_D11_log", 0, 0, 0, true );
   
   Log_1->SetVisAttributes( G4VisAttributes( false, Gas ) );

   new G4PVPlacement( 0, G4ThreeVector( 0.0, 0.0, Z + L ), 
                      "BP_D11_phys", Log_1, World_phys, false, 0, true );

   // Create the tube and place it.

   Solid_2 = new G4Tubs( "BP_D12_solid", ID, OD, L, 0.0, Deg360 );

   Log_2 = new G4LogicalVolume( Solid_2, G4Material::GetMaterial( "SST316" ),
                                "BP_D12_log", 0, 0, 0, true );

   Log_2->SetVisAttributes( G4VisAttributes( true, SST ) );

   new G4PVPlacement( 0, G4ThreeVector(),
                      Log_2, "BP_D12_phys", Log_1, false, 0, true );

   Z += 2.0 * L;

   // -------------------------------------------------------------------------

   // Dimensions for short SST transition.

   OD = 2.500 * 2.54 * cm / 2.0;
   ID = 2.375 * 2.54 * cm / 2.0;
   L  = 0.070 * 2.54 * cm / 2.0;

   // Create the volume and place it.

   Solid_1 = new G4Tubs( "BP_D13_solid", 0.0, OD, L, 0.0, Deg360 );

   Log_1 = new G4LogicalVolume( Solid_1, G4Material::GetMaterial( "Beam_gas" ),
                                "BP_D13_log", 0, 0, 0, true );
   
   Log_1->SetVisAttributes( G4VisAttributes( false, Gas ) );

   new G4PVPlacement( 0, G4ThreeVector( 0.0, 0.0, Z + L ), 
                      "BP_D13_phys", Log_1, World_phys, false, 0, true );

   // Create the tube and place it.

   Solid_2 = new G4Tubs( "BP_D14_solid", ID, OD, L, 0.0, Deg360 );

   Log_2 = new G4LogicalVolume( Solid_2, G4Material::GetMaterial( "SST316" ),
                                "BP_D14_log", 0, 0, 0, true );

   Log_2->SetVisAttributes( G4VisAttributes( true, SST ) );

   new G4PVPlacement( 0, G4ThreeVector(),
                      Log_2, "BP_D14_phys", Log_1, false, 0, true );

   Z += 2.0 * L;

   // -------------------------------------------------------------------------

   // Dimensions for 2.5" to 6" cone.

   OD1 = 2.500 * 2.54 * cm / 2.0;
   OD2 = 6.000 * 2.54 * cm / 2.0;
   ID1 = 2.375 * 2.54 * cm / 2.0;
   ID2 = 5.760 * 2.54 * cm / 2.0;

   L   = 8.375 * 2.54 * cm / 2.0;

   // Create the volume and place it.

   Solid_1 = new G4Cons( "BP_D15_solid", 0.0, OD1, 0.0, OD2, L, 0.0, Deg360 );

   Log_1 = new G4LogicalVolume( Solid_1, G4Material::GetMaterial( "Beam_gas" ),
                                "BP_D15_log", 0, 0, 0, true );
   
   Log_1->SetVisAttributes( G4VisAttributes( false, Gas ) );

   new G4PVPlacement( 0, G4ThreeVector( 0.0, 0.0, Z + L ), 
                      "BP_D15_phys", Log_1, World_phys, false, 0, true );

   // Create the cone and place it.

   Solid_2 = new G4Cons( "BP_D16_solid", ID1, OD1, ID2, OD2, L, 0.0, Deg360 );

   Log_2 = new G4LogicalVolume( Solid_2, G4Material::GetMaterial( "SST316" ),
                                "BP_D16_log", 0, 0, 0, true );

   Log_2->SetVisAttributes( G4VisAttributes( true, SST ) );

   new G4PVPlacement( 0, G4ThreeVector(),
                      Log_2, "BP_D16_phys", Log_1, false, 0, true );

   Z += 2.0 * L;

   // -------------------------------------------------------------------------

   // Dimensions for short SST transition.

   OD = 6.000 * 2.54 * cm / 2.0;
   ID = 5.760 * 2.54 * cm / 2.0;
   L  = 0.375 * 2.54 * cm / 2.0;

   // Create the volume and place it.

   Solid_1 = new G4Tubs( "BP_D17_solid", 0.0, OD, L, 0.0, Deg360 );

   Log_1 = new G4LogicalVolume( Solid_1, G4Material::GetMaterial( "Beam_gas" ),
                                "BP_D17_log", 0, 0, 0, true );
   
   Log_1->SetVisAttributes( G4VisAttributes( false, Gas ) );

   new G4PVPlacement( 0, G4ThreeVector( 0.0, 0.0, Z + L ), 
                      "BP_D17_phys", Log_1, World_phys, false, 0, true );

   // Create the tube and place it.

   Solid_2 = new G4Tubs( "BP_D18_solid", ID, OD, L, 0.0, Deg360 );

   Log_2 = new G4LogicalVolume( Solid_2, G4Material::GetMaterial( "SST316" ),
                                "BP_D18_log", 0, 0, 0, true );

   Log_2->SetVisAttributes( G4VisAttributes( true, SST ) );

   new G4PVPlacement( 0, G4ThreeVector(),
                      Log_2, "BP_D18_phys", Log_1, false, 0, true );

   Z += 2.0 * L;

   // -------------------------------------------------------------------------

   // Dimensions for 6" beampipe.

   OD =  6.000 * 2.54 * cm / 2.0;
   ID =  5.760 * 2.54 * cm / 2.0;
   L  = 68.625 * 2.54 * cm / 2.0;

   // Create the volume and place it.

   Solid_1 = new G4Tubs( "BP_D19_solid", 0.0, OD, L, 0.0, Deg360 );

   Log_1 = new G4LogicalVolume( Solid_1, G4Material::GetMaterial( "Beam_gas" ),
                                "BP_D19_log", 0, 0, 0, true );
   
   Log_1->SetVisAttributes( G4VisAttributes( false, Gas ) );

   new G4PVPlacement( 0, G4ThreeVector( 0.0, 0.0, Z + L ), 
                      "BP_D19_phys", Log_1, World_phys, false, 0, true );

   // Create the tube and place it.

   Solid_2 = new G4Tubs( "BP_D20_solid", ID, OD, L, 0.0, Deg360 );

   Log_2 = new G4LogicalVolume( Solid_2, G4Material::GetMaterial( "SST316" ),
                                "BP_D20_log", 0, 0, 0, true );

   Log_2->SetVisAttributes( G4VisAttributes( true, SST ) );

   new G4PVPlacement( 0, G4ThreeVector(),
                      Log_2, "BP_D20_phys", Log_1, false, 0, true );

   Z += 2.0 * L;

   // -------------------------------------------------------------------------

   // Dimensions for short SST transition.

   OD = 6.000 * 2.54 * cm / 2.0;
   ID = 5.760 * 2.54 * cm / 2.0;
   L  = 0.375 * 2.54 * cm / 2.0;

   // Create the volume and place it.

   Solid_1 = new G4Tubs( "BP_D21_solid", 0.0, OD, L, 0.0, Deg360 );

   Log_1 = new G4LogicalVolume( Solid_1, G4Material::GetMaterial( "Beam_gas" ),
                                "BP_D21_log", 0, 0, 0, true );
   
   Log_1->SetVisAttributes( G4VisAttributes( false, Gas ) );

   new G4PVPlacement( 0, G4ThreeVector( 0.0, 0.0, Z + L ), 
                      "BP_D21_phys", Log_1, World_phys, false, 0, true );

   // Create the tube and place it.

   Solid_2 = new G4Tubs( "BP_D22_solid", ID, OD, L, 0.0, Deg360 );

   Log_2 = new G4LogicalVolume( Solid_2, G4Material::GetMaterial( "SST316" ),
                                "BP_D22_log", 0, 0, 0, true );

   Log_2->SetVisAttributes( G4VisAttributes( true, SST ) );

   new G4PVPlacement( 0, G4ThreeVector(),
                      Log_2, "BP_D22_phys", Log_1, false, 0, true );

   Z += 2.0 * L;

   // -------------------------------------------------------------------------

   // Dimensions for 6" to 1.5" cone.

   OD1 = 6.000 * 2.54 * cm / 2.0;
   OD2 = 1.500 * 2.54 * cm / 2.0;
   ID1 = 5.760 * 2.54 * cm / 2.0;
   ID2 = 1.370 * 2.54 * cm / 2.0;

   L   = 8.375 * 2.54 * cm / 2.0;

   // Dimensions for tube for SM detector.

   OD = 1.0 * 2.54 * cm / 2.0;
   ID = 0.87 * 2.54 * cm / 2.0;
   G4double L1  = L;

   G4double angle = 1.25 * degree;

   // Create the cone.

   Solid_1 = new G4Cons( "BP_D23_solid", 0.0, OD1, 0.0, OD2, L, 0.0, Deg360 );

   // Create the tube for the SM detector.

   Solid_2 = new G4Tubs( "BP_D24_solid", 0.0, OD, L1, 0.0, Deg360 );

   // Form union.

   G4RotationMatrix * rot_1 = new G4RotationMatrix;
   rot_1->rotateY( angle );

   G4ThreeVector shift_1( 2.632 * 2.54 * cm - L1 * sin(angle), 0.0, L1 - L );

   Solid_3 = new G4UnionSolid( "BP_T1", Solid_1, Solid_2, rot_1, shift_1 );

   G4RotationMatrix * rot_2 = new G4RotationMatrix;
   rot_2->rotateY( -angle );

   G4ThreeVector shift_2( -2.632 * 2.54 * cm + L1 * sin(angle), 0.0, L1 - L );

   Solid_4 = new G4UnionSolid( "BP_T2", Solid_3, Solid_2, rot_2, shift_2 );

   Log_1 = new G4LogicalVolume( Solid_4, G4Material::GetMaterial( "SST316" ),
                                "BP_D23_log", 0, 0, 0, true );
   
   Log_1->SetVisAttributes( G4VisAttributes( true, SST ) );

   new G4PVPlacement( 0, G4ThreeVector( 0.0, 0.0, Z + L ), 
                      "BP_D23_phys", Log_1, World_phys, false, 0, true );

   // Repeat for inside volume.

   // Create the cone.

   Solid_1 = new G4Cons( "BP_D25_solid", 0.0, ID1, 0.0, ID2, L, 0.0, Deg360 );

   // Create the tube for the SM detector.

   Solid_2 = new G4Tubs( "BP_D26_solid", 0.0, ID, L1, 0.0, Deg360 );

   // Create union.

   G4RotationMatrix * rot_3 = new G4RotationMatrix;
   rot_3->rotateY( angle );

   G4ThreeVector shift_3( 2.632 * 2.54 * cm - L1 * sin(angle), 0.0, L1 - L );

   Solid_3 = new G4UnionSolid( "BP_T3", Solid_1, Solid_2, rot_3, shift_3 );

   G4RotationMatrix * rot_4 = new G4RotationMatrix;
   rot_4->rotateY( -angle );

   G4ThreeVector shift_4( -2.632 * 2.54 * cm + L1 * sin(angle), 0.0, L1 - L );

   Solid_4 = new G4UnionSolid( "BP_T4", Solid_3, Solid_2, rot_2, shift_2 );

   Log_2 = new G4LogicalVolume( Solid_4, G4Material::GetMaterial( "Beam_gas" ),
                                "BP_D25_log", 0, 0, 0, true );
   
   Log_2->SetVisAttributes( G4VisAttributes( false, Gas ) );

   new G4PVPlacement( 0, G4ThreeVector(), Log_2, "BP_D25_phys", Log_1,
                      false, 0, true );

   Z += 2.0 * L;

   // -------------------------------------------------------------------------

   // Dimensions for beampipe beside symmetric Moller detector.

   OD =  1.500 * 2.54 * cm / 2.0;
   ID =  1.375 * 2.54 * cm / 2.0;
   L  = 31.635 * 2.54 * cm / 2.0;

   // Create the volume and place it.

   Solid_1 = new G4Tubs( "BP_D27_solid", 0.0, OD, L, 0.0, Deg360 );

   Log_1 = new G4LogicalVolume( Solid_1, G4Material::GetMaterial( "Beam_gas" ),
                                "BP_D27_log", 0, 0, 0, true );
   
   Log_1->SetVisAttributes( G4VisAttributes( false, Gas ) );

   new G4PVPlacement( 0, G4ThreeVector( 0.0, 0.0, Z + L ), 
                      "BP_D27_phys", Log_1, World_phys, false, 0, true );

   // Create the tube and place it.

   Solid_2 = new G4Tubs( "BP_D28_solid", ID, OD, L, 0.0, Deg360 );

   Log_2 = new G4LogicalVolume( Solid_2, G4Material::GetMaterial( "SST316" ),
                                "BP_D28_log", 0, 0, 0, true );

   Log_2->SetVisAttributes( G4VisAttributes( true, SST ) );

   new G4PVPlacement( 0, G4ThreeVector(),
                      Log_2, "BP_D28_phys", Log_1, false, 0, true );

   Z += 2.0 * L;

   // -------------------------------------------------------------------------
/*
// Go back and add ports for symmetric Moller.

Z = 89.496 * 2.54 * cm;

// -------------------------------------------------------------------------

// Flange on end of SM tube.

OD = 2.73 * 2.54 * cm / 2.0;
ID = 0.94 * 2.54 * cm / 2.0;
L  = 1.00 * 2.54 * cm / 2.0;

// Create the volume and place it.

Solid_1 = new G4Tubs( "BP_D27_solid", 0.0, OD, L, 0.0, Deg360 );

Log_1 = new G4LogicalVolume( Solid_1, G4Material::GetMaterial( "Beam_gas" ),
"BP_D27_log", 0, 0, 0, true );
   
Log_1->SetVisAttributes( G4VisAttributes( false, Gas ) );

new G4PVPlacement( 0, G4ThreeVector( 0.0, 0.0, Z + L ), 
"BP_D27_phys", Log_1, World_phys, false, 0, true );

// Create the tube and place it.

Solid_2 = new G4Tubs( "BP_D28_solid", ID, OD, L, 0.0, Deg360 );

Log_2 = new G4LogicalVolume( Solid_2, G4Material::GetMaterial( "SST316" ),
"BP_D28_log", 0, 0, 0, true );

Log_2->SetVisAttributes( G4VisAttributes( true, SST ) );

new G4PVPlacement( 0, G4ThreeVector(),
Log_2, "BP_D28_phys", Log_1, false, 0, true );
*/
   // -------------------------------------------------------------------------

   cout << "     done.\n" << endl << flush;

   // That's All Folks !

   return;

}