Geant4系列講座二

1、提 綱一、Geant4運行模式“purely hard-coded” batch modeBatch mode，macro commandsInteractive mode，command lines二、材料定義簡單物質(zhì)分子定義混合物同位素Geant4自定義三、Geant4中使用物理量的單位基本單位輸入輸出四、幾何結(jié)構定義簡單結(jié)構定義復雜結(jié)構定義顏色顯示五PrimaryGeneratorAction一、Geant4運行模式 Geant4運行模式：“purely hard-coded” batch modeBatch mode，macro commandsInteractive mode，com

2、mand lines每種模式的選擇必須在Main文件中編制相應的代碼以實現(xiàn)其對應模式。通常采用混合模式。.頭文件 Purely batch-coded main(). . . G4runManager初始化. . . class初始化G4核初始化 runManager-Initialize();/start runG4int numberOfEvent = 3; runManager-BeamOn(numberOfEvent);delete runManager; return 0;.頭文件 Batch-coded with macro file main(

3、int argc,char* argv). . . G4runManager初始化. . . class初始化G4核初始化 runManager-Initialize();/ Get the pointer to the UI manager G4UImanager* UI = G4UImanager:GetUIpointer();G4String command = /control/execute ;G4String fileName = argv1;UI-applyCommand(command+fileName);delete runManager; return 0;.頭文件 Int

4、eractive by command line mode.#include G4UIterminal.hh#include G4UIsession.hhint main(int argc,char* argv). . . G4runManager初始化. . . class初始化G4核初始化 runManager-Initialize();/ Terminal initialization;G4UIsession* session = new G4UIterminal;session-SessionStart();delete runManager; return 0;Macro file:

5、命令行序列：#2008.6.9 #mac file for visulization/vis/scene/create/vis/open OGLIX/vis/scene/add/trajectories/vis/scene/add/hits/vis/scene/endOfEventAction accumulate/vis/viewer/set/viewpointThetaPhi 72 25 /vis/viewer/zoom 16/run/beamOn 10000/vis/viewer/set/style w/vis/viewer/set/style s以文本格式保存#include G4UI

6、manager.hh Mixed mode#include G4RunManager.hh .#include G4VisManager.hh#include G4VisExecutive.hh#include G4UItcsh.hh#include G4UIterminal.hh#include G4UIsession.hhint main(int argc,char* argv)G4RunManager* MyRun = new G4RunManager;/this part is for the visualizationG4VisManager* VisManager = new G4

7、VisExecutive;VisManager-Initialize();MyRun-Initialize();/G4UIsession* session = new G4UIterminal(new G4UItcsh);G4UImanager* UI = G4UImanager:GetUIpointer(); Mixed modeif(argc=1)UI-ApplyCommand(/run/verbose 2);G4String command=/control/execute /g4work/pphotonelectron/vis.mac;UI-ApplyCommand(command);

8、/session-SessionStart();elseUI-ApplyCommand(/run/verbose 2);G4String command=/control/execute /g4work/pphotonelectron/;G4String fileName = argv1;UI-ApplyCommand(command+fileName);/session-SessionStart();/delete session;delete VisManager;delete MyRun;return 0;二、材料定義 一般的物質(zhì)（化合物，混合物）是由元素構成，元素又由同位素組成。按照這

9、種物質(zhì)的劃分層次，可以通過類似的概念定義宏觀世界中的物質(zhì)。 Geant4中定義的物質(zhì)類（class）有兩種：G4ElementG4Material G4Element class 描述微觀層面的原子的性質(zhì)如:原子序數(shù)核子數(shù)殼層能量諸如原子截面等 G4Isotope class 描述微觀層面的原子的性質(zhì)如:原子序數(shù)核子數(shù)莫爾質(zhì)量等 G4Material class 描述微觀層面的原子的性質(zhì)如:原子序數(shù)核子數(shù)殼層能量諸如原子截面等簡單物質(zhì)定義：G4double density = 1.390*g/cm3;G4double a = 39.95*g/mole;G4Material* lAr = new

10、 G4Material(name=liquidArgon, z=18., a, density);分子定義：a = 1.01*g/mole;G4Element* elH = new G4Element(name=Hydrogen,symbol=H , z= 1., a);a = 16.00*g/mole;G4Element* elO = new G4Element(name=Oxygen ,symbol=O , z= 8., a);density = 1.000*g/cm3;G4Material* H2O = new G4Material(name=Water,density,ncompone

11、nts=2);H2O-AddElement(elH, natoms=2);H2O-AddElement(elO, natoms=1);混合物定義（質(zhì)量份數(shù)）：a = 14.01*g/mole;G4Element* elN = new G4Element(name=Nitrogen,symbol=N , z= 7., a);a = 16.00*g/mole;G4Element* elO = new G4Element(name=Oxygen ,symbol=O , z= 8., a);density = 1.290*mg/cm3;G4Material* Air = new G4Material(

12、name=Air ,density,ncomponents=2);Air-AddElement(elN, fractionmass=70*perCent);Air-AddElement(elO, fractionmass=30*perCent);Geant4自定義：G4NistManager* man = G4NistManager:Instance();G4Material* H2O = man-FindOrBuildMaterial(G4_WATER);G4Material* Air = man-FindOrBuildMaterial(G4_AIR);同位素定義：G4Isotope* U5

13、 = new G4Isotope(name=U235, iz=92, n=235, a=235.01*g/mole);G4Isotope* U8 = new G4Isotope(name=U238, iz=92, n=238, a=238.03*g/mole);G4Element* elU = new G4Element(name=“enriched Uranium”, symbol=“U”, ncomponents );elU-AddIsotope(U5, abundance= 90.*perCent);elU-AddIsotope(U8, abundance= 10.*perCent);三

14、、Geant4中使用物理量的單位基本單位：Geant4中用戶可以為選定的物理量選擇各種單位，但是Geant4內(nèi)核內(nèi)定義了如下基本單位：millimeter (mm)nanosecond (ns)Mega electron Volt (MeV)positron charge (eplus)degree Kelvin (kelvin)the amount of substance (mole)luminous intensity (candela)radian (radian)steradian (steradian)其它所有單位都以上述單位為基礎得到，如：Millimeter mm 1；Mete

15、r m 1000*mm；用戶輸入數(shù)據(jù)單位： Geant4中用戶輸入的數(shù)據(jù)必須帶有單位（系統(tǒng)默認強烈建議不使用），如： G4double Size = 15*km, KineticEnergy = 90.3*GeV, density = 11*mg/cm3; 同樣，如果數(shù)據(jù)為數(shù)組格式或者從文件讀入，也必須帶有單位，如： for (int j=0, jjmax, j+) CrossSectionj *= millibarn;數(shù)據(jù)輸出單位： 帶單位數(shù)據(jù)輸出格式如： G4cout KineticEnergy/keV keV; G4cout density/(g/cm3) g/cm3; 或者給出Gean

16、t4選擇的最優(yōu)化單位： G4cout G4BestUnit(StepSize, Length);四、幾何結(jié)構定義 Geant4中以“體”（Volume）的概念定義幾何形狀。模型中最大的“體”稱為“世界體”（World Volume），其它的體都位于世界體內(nèi)部。“世界體”內(nèi)的“體”之間是包含和被包含關系，被包含的稱包含它的體為母體（mother Volume）。 Geant4中的體的定義包含三個層次：1.定義幾何形狀；2.定義物理屬性；3.定義所在母體的位置； 定義幾何形狀（solid）：G4double expHall_x = 30.0*m; G4double expHall_y = 40.0

17、*m; G4double expHall_z = 60.0*m; G4Box* experimentalHall_box = new G4Box(expHall_box,expHall_x,expHall_y,expHall_z); 指定幾何形狀的名稱、尺寸等信息。 定義物理屬性：G4LogicalVolume* experimentalHall_log = new G4LogicalVolume(experimentalHall_box,Ar,expHall_log);給定物理屬性指向的幾何體，該幾何體對應的物質(zhì)，該幾何體的名稱等信息。G4LogicalVolume* tracker_log

18、 = new G4LogicalVolume(tracker_tube,Al,tracker_log); 定義物理位置 G4double trackerPos_x = -1.0*meter; G4double trackerPos_y = 0.0*meter; G4double trackerPos_z = 0.0*meter; G4VPhysicalVolume* tracker_phys = new G4PVPlacement(0, / no rotation G4ThreeVector(trackerPos_x,trackerPos_y,trackerPos_z), / translat

19、ion position tracker_log, / its logical volume tracker, / its name experimentalHall_log, / its mother (logical) volume false, / no boolean operations 0); / its copy number 復雜幾何體結(jié)構C循環(huán)設計 G4double calo_x = 1.*cm; G4double calo_y = 40.*cm; G4double calo_z = 40.*cm; G4Box* calorimeterLayer_box = new G4Bo

20、x(caloLayer_box, calo_x,calo_y,calo_z); calorimeterLayer_log = new G4LogicalVolume(calorimeterLayer_box, Al,caloLayer_log,0,0,0); for(G4int i=0;iSetVisAttributes(G4Colour(0,0,0);tracker_log-SetVisAttributes(G4Colour(1,0,0);calorimeterBlock_log-SetVisAttributes(G4Colour(0,2,0,0);calorimeterLayer_log-

21、SetVisAttributes(G4Colour(0,1,1,0);RGB配色，G4Colour(0,1,1,0)五、PrimaryGeneratorAction G4VUserPrimaryGeneratorAction是Geant4要求的強制類之一，通過該類指定產(chǎn)生的主粒子事件。在該類中，用戶可以指定粒子產(chǎn)生的方式。 在G4VUserPrimaryGeneratorAction中，用戶必須對主粒子產(chǎn)生器實例化。實際上，在G4VUserPrimaryGeneratorAction中，用戶定義的是主粒子產(chǎn)生的排列順序及初始化設定。 產(chǎn)生主粒子事件的方法射線束，可以選擇粒子類型、能量、射線束極

22、化度等信息許多是以FORTRAN編寫的高能物理過程所需的粒子事件ASCII 文件輸入提供了很多方便的函數(shù)描述粒子源模擬空間環(huán)境、地下放射性源等；（類似于現(xiàn)實中的源） 例子N01中PrimaryGeneratorAction使用ParticleGun作為的主粒子產(chǎn)生器PrimaryGeneratorAction示例（N01）每次產(chǎn)生一個粒子（Geantino），圖中綠色線條；GPS的使用和ParticleGun類似，替代即可；#ifndef ExN01PrimaryGeneratorAction_h#define ExN01PrimaryGeneratorAction_h 1#include G

23、4VUserPrimaryGeneratorAction.hhclass G4ParticleGun;class G4Event;class ExN01PrimaryGeneratorAction : public G4VUserPrimaryGeneratorActionpublic:ExN01PrimaryGeneratorAction();ExN01PrimaryGeneratorAction();public:void generatePrimaries(G4Event* anEvent);private:G4ParticleGun* particleGun; #endif Prima

24、ryGeneratorAction.hh N01ParticleGun實例化#include ExN01PrimaryGeneratorAction.hh#include G4Event.hh#include G4ParticleGun.hh#include G4ThreeVector.hh#include G4Geantino.hh#include globals.hhExN01PrimaryGeneratorAction:ExN01PrimaryGeneratorAction()G4int n_particle = 1;particleGun = new G4ParticleGun(n_p

25、article);particleGun-SetParticleDefinition(G4Geantino:GeantinoDefinition();particleGun-SetParticleEnergy(1.0*GeV);particleGun-SetParticlePosition(G4ThreeVector(-2.0*m,0.0*m,0.0*m);ExN01PrimaryGeneratorAction:ExN01PrimaryGeneratorAction()delete particleGun;PrimaryGeneratorAction.cc N01void ExN01Prima

26、ryGeneratorAction:generatePrimaries(G4Event* anEvent)G4int i = anEvent-get_eventID() % 3;switch(i)case 0:particleGun-SetParticleMomentumDirection(G4ThreeVector(1.0,0.0,0.0);break;case 1:particleGun-SetParticleMomentumDirection(G4ThreeVector(1.0,0.1,0.0);break;case 2:particleGun-SetParticleMomentumDirection(G4ThreeVector(1.0,0.0,0.1);break;particleGun-generatePrimaryVertex(anEvent);PrimaryGeneratorAction.cc N01G4ParticleGun 方法 void SetParticleDefinition(G4ParticleDefinition*) void SetParticleMomentum(G4Part