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Question Inconsistent mass and density of volume. 

Forum: Geometry
Date: 08 May, 2014
From: Joel Klinger <Joel Klinger>

Hi Geometry experts,

I have 3 concentric volumes: "Rock" which contains "Container" which contains "LiquidArgon". Each is the logical mother volume of the previous eg:

physiContainer = new G4PVPlacement(0,    // no rotation                                                                                         
                                                            positionContainer,// at (x,y,z)                                                                                          
                                                            logicContainer,     // its logical volume                                                                                  
                                                            containerName,    // its name                                                                                            
                                                            logicRock,            // its mother  volume                                                                                  
                                                            false,                   // no boolean operations                                                                               
                                                            0);                       // copy number                                                                                         

They are composed as follows: "Rock" is composed of a user material "rock" "Container is composed of a user material "stainlesssteel" "LiquidArgon" is composed of a user material "LiqArgon"

I would like to check that the LiquidArgon volume has an associated mass of 20kT. I set the density of LiqArgon like this (1.39 g/cm^3):

//---- Liquid Argon                                                                                                                                         
G4Material* LiqArgon = new G4Material("LiqArgon", z=18., a=39.948*g/mole, density= 1.3928*g/cm3, 
                                                               kStateLiquid, temperature= 87.25*kelvin, pressure= 1.0*atmosphere);

I set the Liquid Argon volume like this:

//---- Place LAr target G4ThreeVector positionTarget = G4ThreeVector(0,0,0); G4double targetInnerRad = 0.0; G4double targetOuterRad = 15*m; G4double targetHalfLength = 10*m; G4double targetMinAngle = 0.*deg; G4double targetAngularExtent = 360.*deg; G4String targetName = "target";

solidVolume = new G4Tubs(targetName, targetInnerRad, targetOuterRad, targetHalfLength,targetMinAngle,targetAngularExtent);

If I calculate this volume manually I get 1.41372e+13 mm^3, and if I call solidVolume->GetCubicVolume() I also get 1.41372e+13 mm^3, so this is good. Furthermore (1.39 g/cm^3)*(.41372e+13 mm^3) = 20kT - which is great.

From now on I run into trouble. If I do logicVolume->GetMaterial()->GetDensity() I get "8.69317e+18", which looks wrong in any system of units. Furthermore if I do logicVolume->GetMass() I get "1.22897e+32", which also looks wrong regardless of the units.

My question: For my sanity - what do GetMass() and GetMaterial()->GetDensity() actually return? Is it the combined mass and density of the Rock + Container + Liquid Argon?

Thanks for your help, Joel

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1 None: Re: Inconsistent mass and density of volume.   (Michael H. Kelsey - 08 May, 2014)
(_ Ok: Re: Inconsistent mass and density of volume.   (Joel Klinger - 09 May, 2014)
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