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Question Problem in deuteron inelastic for plasma focus fusion  

Forum: Fast Simulation, Transportation & Others
Date: 09 May, 2002
From: Lam Yihua <Lam Yihua>

dear experts,

Sorry... I dont know where shall i put this Question...
How's ur life there? :)
Currently, I'm working with condensed plasma.

At the plasma focus situation, the deuterium'll confined into a condensed volume
volume  = ~1*e-6 m3
density  = ~1*e19  particles/cm3
temperature = ~10 MeV

1) Well, i assume this situation can be created as a "detector" or "material"
2)  I assume no ion in that condensed volume

3) so, i made a volume to contain such condense plasma.
 
in my own class DetectorConstruction:


*********************************************************
G4VPhysicalVolume* LamCoDetectorConstruction::Construct()
{
   ...
   ...

  //------------------------------------------------------
  // Condensed Plasma Gas
  //------------------------------------------------------
  G4double const pi    = 3.1416;
  G4double const radius    = 0.1 *cm;
  G4double const length = 1.0 *cm;

G4double const ParticlePerML              = pow(19, 10);  
G4double const CondensedPlasmaTemperature = 110000000;
G4double const BoltzmanConst              = 1.380658*pow(-23, 10);
G4double const volume              = length*pi*(radius*radius);

G4double const CondensedPlasmaPressure    
               = (ParticlePerML*BoltzmanConst*CondensedPlasmaTemperature);
           

density         = CalculatedDensity*mg/cm3;
pressure        = (CondensedPlasmaPressure*9.869*pow(-6, 10)) *atmosphere;
temperature     = (CondensedPlasmaTemperature)*kelvin;


  //
  // Deuterium
  //
G4Material *CondensedPlasmaDeuterium = new G4Material(name="CondensedPlasmaDeuterium", density, ncomponents=1,
                                     kStateGas,temperature,pressure);
CondensedPlasmaDeuterium->AddElement(D, natoms=1);

 ...
 ...

}
***********************************************
4)  In the PhysicsList, i'd added in DeuteronInelastic process:

***********************************************
void ExN01PhysicsList::ConstructNeutronCollision()
{
    ....
    ....

   // Deuteron
  else if (particleName == "deuteron")
     {
G4DeuteronInelasticProcess *theDeuteronInelasticProcess
               = new G4DeuteronInelasticProcess("DeuteronInelastic");

  theLEDeuteronModel = new G4LEDeuteronInelastic;

 
  theLEDeuteronModel->SetMinEnergy(0.000001*eV);
  //theLENeutronModel->SetMaxEnergy(14*MeV);
 
  theDeuteronInelasticProcess->RegisterMe(theLEDeuteronModel);
  pManager->AddDiscreteProcess(theDeuteronInelasticProcess);
     }

  ....
  ....
}

***********************************************
5) When plasma focus occurs, deuterium in that condensed volume
will collide with one another to produce fusion. The expected outcome
are neutrons and deuterons+.

I assume deuteron will be created during plasma focus, then I
used GSPM class to create Deuteron, and stated the created
deuteron in the middle of that condensed plasma volume above.

I think after Deuteron created from Geant4 with GSPM
that Deuteron will interact with deuterium atoms in
condensed volume deuterium to produce neutrons.

below is the macro file for using GSPM
***********************************************

/gps/particle deuteron
/gps/type Volume
/gps/shape Cylinder
/gps/centre -10. 0. 0. cm
/gps/posrot1 1. 0. 0.
/gps/posrot2 0. 1. 0.
/gps/radius 1.0 mm
/gps/halfz 0.5 cm
/gps/angtype cos
/gps/angrot1 1. 0. 0.
/gps/angrot2 0. 1. 0.
/gps/maxtheta 1. deg
/gps/energytype Mono
/gps/monoenergy 1. MeV


/run/beamOn 1

***********************************************
6) but the output of the simulation is
***********************************************

Start Run processing.
=====================================
G4EventManager::ProcessOneEvent()
=====================================
1 vertices passed from G4Event.
G4PrimaryTransformer::PrimaryVertex (-99.4487(mm),0.476494(mm),0.582398(mm),0(nsec))
Primary particle (deuteron) --- Transfered with momentum (-8.22679,-6.97099,-8.44329)
A new track 0x8085150 (trackID 1, parentID 0) is passed to G4StackManager.
1 primaries are passed from G4EventTransformer.
!!!!!!! Now start processing an event !!!!!!!
### pop requested out of 1 stacked tracks.
Selected G4StackedTrack : 0x8090030 with G4Track 0x8085150 (trackID 1, parentID 0)
Track 0x8085150 (trackID 1, parentID 0) is passed to G4TrackingManager.

*********************************************************************************************************
* G4Track Information:   Particle = deuteron,   Track ID = 1,   Parent ID = 0
*********************************************************************************************************

Step#    X(mm)    Y(mm)    Z(mm) KinE(MeV)  dE(MeV) StepLeng TrackLeng  NextVolume ProcName
0    -99.4    0.476    0.582      1.        0        0         0 innerChamber           initStep
Track (trackID 1, parentID 0) is processed with stopping code 2
### pop requested out of 0 stacked tracks.
### 0 waiting tracks are re-classified to
0 urgent tracks and 0 waiting tracks.
NULL returned from G4StackManager.
Terminate current event processing.
Run terminated.
Run Summary
Number of events processed : 1
User=0s Real=0.01s Sys=0.01s

**********************************************
7) the Deuteron produced didnt collide with deuterium atom in that confined volume and fly into another
volume (innerChamber), and no more process had been carried out.... :(

8) I think :
a) the method i used to simulate deuteron-deuteron collision/interaction to produced fused neutron
    is wrong. Perhaps there's a better way to do so, could u please suggest some method for me to do with
    GEANT4?

b) the physics process i added in for Deuteron Inelastic may not suitable for this situation.
    Shall I need to define other physics process for Deuteron Inelastic to produce fused neutron?
       
c) The data library may not support the energy range situation?

d) Is it possible for me to fill in the Logical volume of a "detector" with ion, like H+?


thanks... :)


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