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Question Concentric cylinders and energy deposition 

Forum: Geometry
Date: 13 Oct, 2005
From: Gabriel Sawakuchi <Gabriel Sawakuchi>

Hello,

I am a new user and I am not sure if this is the right forum for my question. Anyway, I would like to get the total energy deposited by delta rays in concentric cylinders when an ion pass through the axis of the inner cylinder.

I have modified the Geometry of example Testm7 but I think I am doing something wrong.

Case 1: The energy deposited
in the inner cylinder (tally1 0) 
(RMin=0, RMax=1000 nm,Height = 4000 nm) 
is bigger than that deposited in the
outer cylinder (tally2 0)
(RMin=0, RMax=1000 nm, Height = 4000 nm). 
It should not be correct since the volume of
the outer cylinder is larger and therefore it is expected to
happen more energy deposition events.
             __________
            |          |
            |__________| 
            |(x1,y1,z1)|
    --ion-->|(x2,y2,z2)|
            |__________|
            |          |
            |__________|

----------------------------------------------------------

Cumulated Doses : Edep; Edep/Ebeam; Dose; Mass

tally1 0: 888.22 keV; 0.0088822 %; 4.8624 Gy; 2.9267e-08 mg

tally2 0: 31.704 keV; 0.00031704 %; 0.04339 Gy; 1.1707e-07 mg

----------------------------------------------------------

Case 2: When I set two identical cylinders 
(RMin=0, RMax=1000 nm,Height = 4000 nm)
(same dimension and position) I get 0 eV for energy 
deposition in one of them.
             __________ 
            |(x1,y1,z1)|
    --ion-->|(x2,y2,z2)|
            |__________|

----------------------------------------------------------

Cumulated Doses : Edep; Edep/Ebeam; Dose; Mass

tally1 0: 899.09 keV; 0.0089909 %; 4.9219 Gy; 2.9267e-08 mg

tally2 0: 0 eV; 0 %; 0 Gy; 2.9267e-08 mg

-----------------------------------------------------------

Case 3:. Another strange thing happen when I define only one cylinder
(RMin=0, RMax=1000 nm,Height = 4000 nm).
The energy deposited is different from the case when I have
two cylinders with the same dimensions (Case 2).
             __________ 
            |          |
    --ion-->|(x1,y1,z1)|
            |__________|

------------------------------------------------------------

Cumulated Doses : Edep; Edep/Ebeam; Dose; Mass

tally1 0: 971.71 keV; 0.0097171 %; 5.3195 Gy; 2.9267e-08 mg

------------------------------------------------------------

Case 4: On the other hand, when I have one cylinder in front of the other
through the path of the ion I get reasonable results but different
from the result I get in Case 3 where the first cylinder has the same
dimensions and position.
             __________ __________
            |          |          |
    --ion-->|(x1,y1,z1)|(x2,y2,z2)|
            |__________|__________|

-------------------------------------------------------------

Cumulated Doses : Edep; Edep/Ebeam; Dose; Mass

tally1 0: 941.18 keV; 0.0094118 %; 5.1523 Gy; 2.9267e-08 mg

tally2 0: 946.59 keV; 0.0094659 %; 5.1819 Gy; 2.9267e-08 mg

--------------------------------------------------------------

My geometry:

----------------------------------------------------------

G4Box*
 sWorld = new G4Box("World",					
	     worldSizeX/2,worldSizeYZ,worldSizeYZ);	

G4LogicalVolume*		   			                      
lWorld = new G4LogicalVolume(sWorld,			
                               worldMaterial,		
                              "World");			
G4VPhysicalVolume*                                   
pWorld = new G4PVPlacement(0,				
  			   G4ThreeVector(),		
                           lWorld,			
			   "World",			
                           0,	       		        
                           false,			
                           0);				   
  // Absorber		   
G4Tubs*
sAbsor = new G4Tubs("Absorber",				
	      RMin,absorRMax,absorHeight/2,PhiMin,PhiMax);	

lAbsor = new G4LogicalVolume(sAbsor,			
                             absorMaterial,		
                            "Absorber");		

G4RotationMatrix* Rotation = new G4RotationMatrix();

Rotation->rotateY(90.*deg);

   new G4PVPlacement(Rotation,				
		   G4ThreeVector(),		
                   lAbsor,			
        	   "Absorber",			
                   lWorld,	       		
                   false,			
                   0);				
  // Tallies (optional)
  // Tally 1
if (tally1Number > 0) {      
G4Tubs* 
  sTally1 = new G4Tubs("Tally1",tally1Size.z(), 
      tally1Size.y(),tally1Size.x()/2, PhiMin, PhiMax);
lTally1 = new G4LogicalVolume(sTally1,tallyMaterial,"Tally1");
for (G4int j=0; j<tally1Number; j++)
   {
      pTally1 = new G4PVPlacement(0,				
                          tally1Position[j],		
                          lTally1,			
			  "Tally1",			
                          lAbsor,	       		
                          false,			
                          j);				
    }       
    tally1Mass =(3.141592653589793238*
                (tally1Size.y()*tally1Size.y()*tally1Size.x()-
		tally1Size.z()*tally1Size.z()*tally1Size.x())
		*(tallyMaterial->GetDensity()));
}  
    // Tally 2
if (tally2Number > 0) {    
G4Tubs* sTally2 = new G4Tubs("Tally2",tally2Size.z(), 
        tally2Size.y(),tally2Size.x()/2,PhiMin,PhiMax);
lTally2 = new G4LogicalVolume(sTally2,tallyMaterial,"Tally2"); 
for (G4int j=0; j<tally2Number; j++)
  {
     pTally2 = new G4PVPlacement(0,				
		    tally2Position[j],		
		    lTally2,			
		    "Tally2",			
		    lAbsor,	       		
		    false,			
		    j);				
  }      
  tally2Mass =(3.141592653589793238*
              (tally2Size.y()*tally2Size.y()*tally2Size.x()-
	      tally2Size.z()*tally2Size.z()*tally2Size.x())
	      *(tallyMaterial->GetDensity()));
} 

------------------------------------------------------------------

I would appreciate any help.

Peace,

Gabriel

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1 None: Re: Concentric cylinders and energy deposition   (michel maire - 18 Oct, 2005)
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