一、官網
是西歐核子研究組織(CERN)開發的全能粒子化學模擬器，可用于各類應用場合，包括核醫學、高能化學、輻射防護等。
在官網上，你可以找到的最新版本和文檔，以及廣泛的應用示例和教程。的設計理念基于現代軟件開發的最佳實踐，并采用模塊化結構，容許使用者依據須要選擇特定模塊，便于更好地適應其應用場合。
下邊是一個簡單的事例，展示怎樣使用模擬一個簡單的電子束：
#include "G4RunManager.hh"
#include "G4UImanager.hh"
#include "G4VisExecutive.hh"
#include "DetectorConstruction.hh"
#include "PhysicsList.hh"
#include "PrimaryGeneratorAction.hh"
int main(int argc, char** argv)
{
// Create the detector construction
DetectorConstruction* detector = new DetectorConstruction();
// Create the physics list
PhysicsList* physics = new PhysicsList();
// Create the primary generator action
PrimaryGeneratorAction* primary = new PrimaryGeneratorAction();
// Create the run manager and configure it
G4RunManager* runManager = new G4RunManager();
runManager->SetUserInitialization(detector);
runManager->SetUserInitialization(physics);
runManager->SetUserAction(primary);
// Initialize the Geant4 UI manager
G4UImanager* uiManager = G4UImanager::GetUIpointer();
// Initialize visualization
G4VisManager* visManager = new G4VisExecutive();
visManager->Initialize();
// Run in interactive mode
uiManager->ApplyCommand("/control/execute vis.mac");
// Clean up and exit
delete visManager;
delete runManager;
delete primary;
delete physics;
delete detector;
return 0;
}
二、學習資源
不僅官網上的資源物理實驗模擬器電腦版，還有其他好多學習的資源。其中，grant是一個基于網路的遠程桌面服務，提供一個訪問的實驗環境。
另外，的官網上也有一些教程，包括入門教程和中級教程。這種教程都提供源代碼和示例數據，便捷用戶學習。據悉，還有一些第三方機構和個人提供的課程材料和教學視頻。
以下是官網上提供的一個簡單的教程事例，展示怎樣使用構建一個基本的偵測器和模擬一個質子束：
#include "G4RunManager.hh"
#include "G4UImanager.hh"
#include "G4UIterminal.hh"
#include "G4UItcsh.hh"
#include "G4VisExecutive.hh"
#include "G4UIExecutive.hh"
#include "DetectorConstruction.hh"
#include "PhysicsList.hh"
#include "PrimaryGeneratorAction.hh"
int main(int argc, char** argv)
{
// Create the run manager and configure it
G4RunManager* runManager = new G4RunManager();
runManager->SetUserInitialization(new DetectorConstruction());
runManager->SetUserInitialization(new PhysicsList());
runManager->SetUserAction(new PrimaryGeneratorAction());
// Initialize the Geant4 UI manager
G4UImanager* uiManager = G4UImanager::GetUIpointer();
// Initialize visualization
G4VisManager* visManager = new G4VisExecutive();
visManager->Initialize();
// Initialize the UI
G4UIExecutive* ui = new G4UIExecutive(argc, argv, "tcsh");
uiManager->ApplyCommand("/control/execute vis.mac");
ui->SessionStart();
// Clean up and exit
delete ui;
delete visManager;
delete runManager;
return 0;
}
三、設置通用粒子源
支持多種粒子源類型，包括單個粒子源、多個粒子源、泊松分布粒子源等?？梢酝ㄟ^設置相應的源參數，控制粒子源的屬性和生成數量。
以下是一個簡單的事例，展示怎樣使用構建一個基本的偵測器和模擬一個通用粒子源：
#include "G4RunManager.hh"
#include "G4UImanager.hh"
#include "G4VisExecutive.hh"
#include "DetectorConstruction.hh"
#include "PhysicsList.hh"
#include "PrimaryGeneratorAction.hh"
#include "GeneralParticleSource.hh"
int main(int argc, char** argv)
{
// Create the detector construction
DetectorConstruction* detector = new DetectorConstruction();
// Create the physics list
PhysicsList* physics = new PhysicsList();
// Create the primary generator action
PrimaryGeneratorAction* primary = new PrimaryGeneratorAction();
// Create the general particle source and configure it
GeneralParticleSource* gps = new GeneralParticleSource();
gps->SetParticleEnergy(1.0*GeV);
gps->SetParticleMomentumDirection(G4ThreeVector(0.,0.,1.));
gps->SetParticlePosition(G4ThreeVector(0.,0.,-10.));
// Set the GPS to be the primary generator action
primary->SetParticleSource(gps);
// Create the run manager and configure it
G4RunManager* runManager = new G4RunManager();
runManager->SetUserInitialization(detector);
runManager->SetUserInitialization(physics);
runManager->SetUserAction(primary);
// Initialize the Geant4 UI manager
G4UImanager* uiManager = G4UImanager::GetUIpointer();
// Initialize visualization
G4VisManager* visManager = new G4VisExecutive();
visManager->Initialize();
// Run in interactive mode
uiManager->ApplyCommand("/run/beamOn 100");
// Clean up and exit
delete visManager;
delete runManager;
delete primary;
delete physics;
delete detector;
return 0;
}
四、論壇
峰會是一個開放的社區，任何人都可以在這兒提出問題、分享經驗和知識。峰會上有好多關于的討論和技術支持，對于菜鳥和中級用戶都很有用。
以下是峰會上的一個問題，關于怎么使用模擬一個粒子在材料中的運動軌跡：
// Use the Geant4 tracking manager to initialize the track
G4Track* track = new G4Track(new G4DynamicParticle(G4Proton::Proton(), G4ThreeVector(0.,0.,500.*MeV), 0.), 0., 0.);
G4TrackingManager* trackingManager = G4EventManager::GetEventManager()->GetTrackingManager();
trackingManager->SetStoreTrajectory(true);
trackingManager->SetTrajectory(new G4Trajectory(track));
trackingManager->ProcessOneTrack(track);
// Get the trajectory from the track and store it in a file
G4Trajectory* trajectory = (G4Trajectory*) track->GetUserInformation();
std::ofstream outFile("trajectory.txt");
for(int i=0; iGetPointEntries(); i++) {
G4TrajectoryPoint* point = (G4TrajectoryPoint*) trajectory->GetPoint(i);
outFile << point->GetPosition().x()/mm << " " << point->GetPosition().y()/mm << " " << point->GetPosition().z()/mm << std::endl;
}
outFile.close();
五、有時間概念嗎？
支持時間模擬，可以記錄粒子在模擬中經過的時間和抵達某個特定地點的時間。這對于個別應用場合十分重要，比如核醫學和粒子化學學中的時間幀率。
以下是一個簡單的事例，展示怎樣使用模擬一個粒子在時間上的運動軌跡：
#include "G4RunManager.hh"
#include "G4UImanager.hh"
#include "G4VisExecutive.hh"
#include "DetectorConstruction.hh"
#include "PhysicsList.hh"
#include "PrimaryGeneratorAction.hh"
int main(int argc, char** argv)
{
// Create the detector construction
DetectorConstruction* detector = new DetectorConstruction();
// Create the physics list
PhysicsList* physics = new PhysicsList();
// Create the primary generator action
PrimaryGeneratorAction* primary = new PrimaryGeneratorAction();
// Create the run manager and configure it
G4RunManager* runManager = new G4RunManager();
runManager->SetUserInitialization(detector);
runManager->SetUserInitialization(physics);
runManager->SetUserAction(primary);
// Initialize the Geant4 UI manager
G4UImanager* uiManager = G4UImanager::GetUIpointer();
// Initialize visualization
G4VisManager* visManager = new G4VisExecutive();
visManager->Initialize();
// Run in interactive mode with time tracking
uiManager->ApplyCommand("/tracking/storeTrajectory 1");
uiManager->ApplyCommand("/run/beamOn 100");
// Clean up and exit
delete visManager;
delete runManager;
delete primary;
delete physics;
delete detector;
return 0;
}
結束語
是一個強悍的粒子化學模擬器，且用于各類應用場合。的學習曲線較崎嶇物理實驗模擬器電腦版，并且在把握相關技術后，可以幫助研究人員進行復雜的數學模擬，并為相關領域的研究提供支持。