Design a simulation to determine radiation footprint in HRRL cell.

1.) The ceiling is 4 feet thick

2.) there is PB shiedling between the HRRL accelerator room and the accelerator operator station

3.) the dirt is about 10 feet thick on the wall side where the accelerator is going to be mounted

4.) determine shielding wall thickness for HRRL cavity to reduce dose out the door

5.) Determine shielding for Tungsten converter

Drawing

Get a drawing from facilities documenting the shielding in that cell with dimensions

Denton Dance: x4710, may be able to provide drawings. B119 Beam Lab

Material Definitions

Concrete

Concrete has 6 elements and a density of 2.7 g/cm^3

Element	Atomic Weight (A)	Atomic Number (Z)	Proportion by Weight
1	1.0079	1.	0.004
2	15.9994	8.	0.509
3	26.981539	13	0.034
4	28.0855	14.	0.345
5	40.078	20	0.070
6	55.8474	26.	0.038

GEANT4 code


a = 1.0079*g/mole;
  G4Element* elH  = new G4Element(name="Hydrogen",symbol="H" , z= 1., a);
  a = 15.9994*g/mole;
  G4Element* elO  = new G4Element(name="Oxygen"  ,symbol="O" , z= 8., a);
a = 26.981539*g/mole;
  G4Element* elAl  = new G4Element(name="Aluminum",symbol="Al" , z= 13., a);
a = 28.0855*g/mole;
  G4Element* elSi  = new G4Element(name="Silicon",symbol="Si" , z= 14., a);
a = 40.078*g/mole;
  G4Element* elCa  = new G4Element(name="Calcium",symbol="Ca" , z= 20., a);
a = 55.8474*g/mole;
  G4Element* elNi  = new G4Element(name="Iron",symbol="Fe" , z= 26., a);



  density =2.7*g/cm3;
  G4Material* Concrete = new G4Material(name="Concrete ",density,ncomponents=6);
  Concrete->AddElement(elH, fractionmass=0.4*perCent);
  Concrete->AddElement(elO, fractionmass=50.9*perCent);
 Concrete->AddElement(elAl, fractionmass=3.4*perCent);
 Concrete->AddElement(elSi, fractionmass=34.5*perCent);
 Concrete->AddElement(elCa, fractionmass=7.0*perCent);
 Concrete->AddElement(elNi, fractionmass=3.8*perCent);

Relative Rates

The first step in the simulation will be to compare relative radiation rates at the exit of the accelerator room. The radiation exiting the accelerator room before and after moving the accelerator will be simulated. Although all particles can be tracked we will mostly be interested in gamma and neutron fluxes through the door. The ratio of before/after moving fluxes for gamma and neutron should be plotted as a function of energy.

Geometry

[HRRL room dimension measured by Jason Swanson]

HRRL Geom by Sadiq

what is the thicknes of the walls below.

No dirt inside walls.

Wall Number 3, 4 and 5 are 1 feet thick.

Ceiling is 5 feet thick. Above that is 1st floor metal structure.

GEANT4 Simulation Setup

HRRL Room Top view

Wall is not real wall. Its material is air, this wall is just used as detector to detect particles and photons.

HRRL Room 45 Degree View

HRRL Room Side view

HRRL Electron Source and Tungsten Target 45 Degree View

HRRL Electron Source and Tungsten Target Top View

HRRL New Electron Source

Geant4 Codes

GPS e- Source

/gps/particle e-

/gps/energy 10. MeV

/gps/pos/type Plane

/gps/pos/shape Circle

/gps/pos/radius 0.6 cm

/gps/pos/sigma_r 3 mm

/gps/pos/sigma_x 3 mm

/gps/pos/sigma_y 3 mm

Old Position, -Z direction:

/gps/pos/centre 380 101.6 -93.68 cm

New Postion, X direction:

/gps/pos/centre 66.5 101.6 93.93 cm

/gps/direction 1 0 0

Physics List

File:Physics List.txt

10 MeV Gamma hit 2 meter D2O target to show neutron from disintegrated deuterium.

Yellow: neutron

Red: electron

Gray: gamma

It is better to show the tracking output in 
order to see the physics process and particles created.

Dectector Construction

File:Detector Construction.txt

Electron and photon interactions with the target and the walls

Electron in Target

*********************************************************************************************************
* G4Track Information:   Particle = e-,   Track ID = 8,   Parent ID = 2
*********************************************************************************************************


#Step#      X         Y         Z        KineE    dEStep   StepLeng  TrakLeng    Volume     Process
    1 1.66401 m  1.01473 m  93.5217 cm      0 eV 147.944 keV29.1396 um 29.1396 um       Target       eIoni

Electron go into Wall3

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


#Step#      X         Y         Z        KineE    dEStep   StepLeng  TrakLeng    Volume     Process
    1 1.64085 m  1.03791 m  93.998 cm 9.76788 MeV198.526 keV97.4316 cm 97.4316 cm        World       eIoni

#Step#      X         Y         Z        KineE    dEStep   StepLeng  TrakLeng    Volume     Process
    2 1.67863 m  1.03716 m  93.7509 cm 9.73665 MeV7.70861 keV3.7869 cm 1.01218 m         World       eIoni

#Step#      X         Y         Z        KineE    dEStep   StepLeng  TrakLeng    Volume     Process
    3 2.38158 m  1.04721 m  88.1765 cm 9.53633 MeV 137.3 keV70.5761 cm 1.71795 m         World       eIoni

#Step#      X         Y         Z        KineE    dEStep   StepLeng  TrakLeng    Volume     Process
    4 4.8856 m  1.06243 m  1.22615 m  9.04023 MeV496.099 keV2.5446 m  4.26254 m         World  Transportation

#Step#      X         Y         Z        KineE    dEStep   StepLeng  TrakLeng    Volume     Process
    5  5.194 m   1.034 m  1.28563 m  8.91744 MeV122.789 keV31.6299 cm 4.57884 m         Wall3  Transportation

#Step#      X         Y         Z        KineE    dEStep   StepLeng  TrakLeng    Volume     Process
    6    7.5 m  95.4945 cm 1.63263 m  8.49278 MeV424.668 keV2.34972 m  6.92856 m    OutOfWorld  Transportation

Gamma go into Wall3

*********************************************************************************************************
* G4Track Information:   Particle = gamma,   Track ID = 3,   Parent ID = 1
*********************************************************************************************************


#Step#      X         Y         Z        KineE    dEStep   StepLeng  TrakLeng    Volume     Process
    1 4.8856 m  98.0398 cm 24.6372 cm 78.0395 keV     0 eV 3.08802 m  3.08802 m         World  Transportation

#Step#      X         Y         Z        KineE    dEStep   StepLeng  TrakLeng    Volume     Process
    2  5.194 m  97.6205 cm 17.6225 cm 78.0395 keV     0 eV 31.6305 cm 3.40432 m         Wall3  Transportation

#Step#      X         Y         Z        KineE    dEStep   StepLeng  TrakLeng    Volume     Process
    3 5.97662 m  96.5562 cm -1.78528 mm      0 eV    403 eV 80.2682 cm  4.207 m         World        phot

Gamma go into Wall4


*********************************************************************************************************
* G4Track Information:   Particle = gamma,   Track ID = 2,   Parent ID = 1
*********************************************************************************************************


#Step#      X         Y         Z        KineE    dEStep   StepLeng  TrakLeng    Volume     Process
    1 2.98112 m  1.42043 m  1.8796 m  92.4831 keV     0 eV 1.72044 m  1.72044 m         World  Transportation

#Step#      X         Y         Z        KineE    dEStep   StepLeng  TrakLeng    Volume     Process
    2 3.42618 m  1.53616 m  2.1844 m  92.4831 keV     0 eV 55.1695 cm 2.27214 m         Wall4  Transportation

#Step#      X         Y         Z        KineE    dEStep   StepLeng  TrakLeng    Volume     Process
    3    7.5 m  2.59551 m  4.97442 m  92.4831 keV     0 eV   5.05 m  7.32214 m    OutOfWorld  Transportation

File:Interaction.txt

Radiation Ratio estimate for Wall 8 2/25/10

A GEANT4 simulation was used to compare the radiation footprint of the HRRL before and after its relocation. The ratio of radiation incident at the exit of the accelerator room (identified as Wall #8 in the pictures below) was estimated by tracking electrons, photons, and neutrons.

The red line in the figure below indicates the interaction point of an electron from the HRRL accelerator with a Tungsten radiator used to convert the incident electron into e+e- pairs. The proposed location for the HRRL is to move it just below wall #6 and in front of the "Z" axis label..

The drawing below identifies the location of Wall #8. Wall 8 is composed of air, this wall is just used as detector to detect particles and photons.

Number of particles

Simulation results by number of particles for 10 million run.

Particle	Numbers at Old Position [1]	Numbers at New Position [2]	Ration (new:old)
e-	697728	2397851	3.43665583
gamma	375260	779381	0.481484665

G4 code for registering particles in wall8. Daughter particles are also registered as long as they are in wall8.

if(  fTrack->GetVolume()->GetName() =="Wall8"  && (fTrack->GetDefinition()->GetPDGEncoding()==22 ||fTrack->GetDefinition()->GetPDGEncoding()==11 ||fTrack->GetDefinition()->GetPDGEncoding()==2212 ||fTrack->GetDefinition()->GetPDGEncoding()==2112 ))
  	{   
	if (fTrack->GetDefinition()->GetPDGEncoding()==22 ) //if gamma 
	{     ig++; 
	      outfile 
	       << ig  << " 22 "	
	      <<fTrack->GetKineticEnergy() << " "
	      << fTrack->GetPosition().x()<< " "
	      << fTrack->GetPosition().y()<< " "
	      << fTrack->GetPosition().z()<< " "
	      << fTrack->GetMomentum().x() << " "
	      << fTrack->GetMomentum().y() << " "
	      << fTrack->GetMomentum().z() << " "<< G4endl;}
	if (fTrack->GetDefinition()->GetPDGEncoding()==11 ) //if e-
	{ie++; 
		outfile 
	      << ie  << " 11 "	
	      <<fTrack->GetKineticEnergy() << " "
	      << fTrack->GetPosition().x()<< " "
	      << fTrack->GetPosition().y()<< " "
	      << fTrack->GetPosition().z()<< " "
	      << fTrack->GetMomentum().x() << " "
	      << fTrack->GetMomentum().y() << " "
	      << fTrack->GetMomentum().z() << " "<< G4endl;}
	if (fTrack->GetDefinition()->GetPDGEncoding()==2212 ) //if proton
	{ip++; 
		outfile 
	      << ip  << " 2212 "	
	      <<fTrack->GetKineticEnergy() << " "
	      << fTrack->GetPosition().x()<< " "
	      << fTrack->GetPosition().y()<< " "
	      << fTrack->GetPosition().z()<< " "
	      << fTrack->GetMomentum().x() << " "
	      << fTrack->GetMomentum().y() << " "
	      << fTrack->GetMomentum().z() << " "<< G4endl;}
	if (fTrack->GetDefinition()->GetPDGEncoding()==2112 ) //if neutron
	{in++; 
		outfile 
	      << in  << " 2112 "	
	      <<fTrack->GetKineticEnergy() << " "
	      << fTrack->GetPosition().x()<< " "
	      << fTrack->GetPosition().y()<< " "
	      << fTrack->GetPosition().z()<< " "
	      << fTrack->GetMomentum().x() << " "
	      << fTrack->GetMomentum().y() << " "
	      << fTrack->GetMomentum().z() << " "<< G4endl;}
	}

Energy profile

The figures below illustrate the energy spectrum of radiation entering wall #8 (described above) as predicted by a GEANT4 simulation of the HRRL accelerator room.