G4-ExampleB1/src/DetectorConstruction.cc

#include "DetectorConstruction.hh"

#include "G4Box.hh"
#include "G4Cons.hh"
#include "G4LogicalVolume.hh"
#include "G4NistManager.hh"
#include "G4Orb.hh"
#include "G4PVPlacement.hh"
#include "G4RunManager.hh"
#include "G4Sphere.hh"
#include "G4SystemOfUnits.hh"
#include "G4Trd.hh"

namespace B1 {

// 构造函数
DetectorConstruction::DetectorConstruction() {}

// 构析函数
DetectorConstruction::~DetectorConstruction() {}

// 描述函数
G4VPhysicalVolume* DetectorConstruction::Construct() {
    // NIST 材料查找表
    G4NistManager* nist = G4NistManager::Instance();

    // Envelope 的参数
    // 外层的水箱
    G4double env_sizeXY = 20 * cm, env_sizeZ = 30 * cm;
    G4Material* env_mat = nist->FindOrBuildMaterial("G4_WATER");

    // 检查几何体之间是否重叠
    G4bool checkOverlaps = true;

    // World
    // 整个大环境，超出环境则认为逃逸
    G4double world_sizeXY = 1.2 * env_sizeXY;
    G4double world_sizeZ = 1.2 * env_sizeZ;
    G4Material* world_mat = nist->FindOrBuildMaterial("G4_AIR");

    // 描述几何体
    // solid 几何框架 -> logic 材料 -> physical 放置等操作
    // 定义 World 的框架大小，注意尺寸是半尺寸
    G4Box* solidWorld = new G4Box("World",                                                     // 名称
                                  0.5 * world_sizeXY, 0.5 * world_sizeXY, 0.5 * world_sizeZ);  // 尺寸

    G4LogicalVolume* logicWorld = new G4LogicalVolume(solidWorld,  // 几何框架
                                                      world_mat,   // 材料
                                                      "World");    // 名称

    G4VPhysicalVolume* physWorld = new G4PVPlacement(0,                // 旋转
                                                     G4ThreeVector(),  // 中心位置，必须在 (0,0,0)
                                                     logicWorld,       // 材料
                                                     "World",          // 名称
                                                     0,                // 母体环境（Mother Volume）
                                                     false,            // no boolean operation
                                                     0,                // copy number
                                                     checkOverlaps);   // overlaps checking

    // Envelope
    // World 中的小环境
    G4Box* solidEnv = new G4Box("Envelope",                                            // 名称
                                0.5 * env_sizeXY, 0.5 * env_sizeXY, 0.5 * env_sizeZ);  // 尺寸

    G4LogicalVolume* logicEnv = new G4LogicalVolume(solidEnv,     // 几何框架
                                                    env_mat,      // 材料
                                                    "Envelope");  // 名称

    new G4PVPlacement(0,                // no rotation
                      G4ThreeVector(),  // at (0,0,0)
                      logicEnv,         // logical volume
                      "Envelope",       // name
                      logicWorld,       // Mother Logical Volumes，即 World
                      false,            // no boolean operation
                      0,                // copy number
                      checkOverlaps);   // overlaps checking

    // Shape 1
    G4Material* shape1_mat = nist->FindOrBuildMaterial("G4_A-150_TISSUE");
    G4ThreeVector pos1 = G4ThreeVector(0, 2 * cm, -7 * cm);

    // 圆锥状 Conical section
    G4double shape1_rmina = 0. * cm, shape1_rmaxa = 2. * cm;
    G4double shape1_rminb = 0. * cm, shape1_rmaxb = 4. * cm;
    G4double shape1_hz = 3. * cm;
    G4double shape1_phimin = 0. * deg, shape1_phimax = 360. * deg;
    G4Cons* solidShape1 = new G4Cons("Shape1", shape1_rmina, shape1_rmaxa, shape1_rminb, shape1_rmaxb, shape1_hz,
                                     shape1_phimin, shape1_phimax);

    G4LogicalVolume* logicShape1 = new G4LogicalVolume(solidShape1,  // solid
                                                       shape1_mat,   // material
                                                       "Shape1");    // name

    new G4PVPlacement(0,               // no rotation
                      pos1,            // at position
                      logicShape1,     // logical volume
                      "Shape1",        // name
                      logicEnv,        // mother  volume
                      false,           // no boolean operation
                      0,               // copy number
                      checkOverlaps);  // overlaps checking

    // Shape 2
    G4Material* shape2_mat = nist->FindOrBuildMaterial("G4_BONE_COMPACT_ICRU");
    G4ThreeVector pos2 = G4ThreeVector(0, -1 * cm, 7 * cm);

    // 梯形 Trapezoid
    G4double shape2_dxa = 12 * cm, shape2_dxb = 12 * cm;
    G4double shape2_dya = 10 * cm, shape2_dyb = 16 * cm;
    G4double shape2_dz = 6 * cm;
    G4Trd* solidShape2 = new G4Trd("Shape2",  // name
                                   0.5 * shape2_dxa, 0.5 * shape2_dxb, 0.5 * shape2_dya, 0.5 * shape2_dyb,
                                   0.5 * shape2_dz);  // size

    G4LogicalVolume* logicShape2 = new G4LogicalVolume(solidShape2,  // solid
                                                       shape2_mat,   // material
                                                       "Shape2");    // name

    new G4PVPlacement(0,               // no rotation
                      pos2,            // at position
                      logicShape2,     // logical volume
                      "Shape2",        // name
                      logicEnv,        // mother  volume
                      false,           // no boolean operation
                      0,               // copy number
                      checkOverlaps);  // overlaps checking

    // 设置 Shape2 用于计算剂量
    fScoringVolume = logicShape2;

    // 总是返回大环境的物理体
    return physWorld;
}

}  // namespace B1