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_Geant4 Version: 11.2
_Operating System: Windows 10
_Compiler/Version: MSVC/14.29.30133
_CMake Version: 3.22.1.0
I’m trying to define the same source by different definitions to compare the results. For example, a point source of Co-60:
- Define a point source and decay process:
# specify a physics list
/physics_lists/select Shielding
## initialize geometry and physics
/run/initialize
/process/list Decay
/process/had/rdm/thresholdForVeryLongDecayTime 1.0e+60 year
# Source position and structure
# Co-60
/gps/particle ion
/gps/ion 27 60 0 0
/gps/energy 0
/gps/pos/type Point
/gps/pos/centre 0 0 0 cm
- Define a point source and energy histogram:
# specify a physics list
/physics_lists/select Shielding
## initialize geometry and physics
/run/initialize
# Source position and structure
# Co-60
/gps/particle gamma
/gps/pos/type Point
/gps/pos/centre 0 0 0 cm
/gps/ang/type iso
/gps/ene/type User
/gps/hist/type energy
/gps/hist/point 0.34693 0.000076
/gps/hist/point 0.82606 0.000076
/gps/hist/point 1.173237 0.999736
/gps/hist/point 1.332501 0.999856
/gps/hist/point 2.15857 0.0000111
/gps/hist/point 2.505 2.0E-8
- Define a point source of gammas with different intensities:
# specify a physics list
/physics_lists/select Shielding
## initialize geometry and physics
/run/initialize
# Source position and structure
# Co-60
# Gamma 1
/gps/source/intensity 0.000076 # 0.0076%
/gps/particle gamma
/gps/pos/type Point
/gps/pos/centre 0 0 0 cm
/gps/ang/type iso
/gps/ene/type Mono
/gps/ene/mono 346.93 keV
# Gamma 2
/gps/source/add 0.000076 # 0.0076%
/gps/particle gamma
/gps/pos/type Point
/gps/pos/centre 0 0 0 cm
/gps/ang/type iso
/gps/ene/type Mono
/gps/ene/mono 826.06 keV
# Gamma 3
/gps/source/add 0.999736 # 99.9736%
/gps/particle gamma
/gps/pos/type Point
/gps/pos/centre 0 0 0 cm
/gps/ang/type iso
/gps/ene/type Mono
/gps/ene/mono 1173.237 keV
# Gamma 4
/gps/source/add 0.999856 # 99.9856%
/gps/particle gamma
/gps/pos/type Point
/gps/pos/centre 0 0 0 cm
/gps/ang/type iso
/gps/ene/type Mono
/gps/ene/mono 1332.501 keV
# Gamma 5
/gps/source/add 0.0000111 # 0.00111%
/gps/particle gamma
/gps/pos/type Point
/gps/pos/centre 0 0 0 cm
/gps/ang/type iso
/gps/ene/type Mono
/gps/ene/mono 2158.57 keV
# Gamma 6
/gps/source/add 2.0E-8 # 2.0E-6%
/gps/particle gamma
/gps/pos/type Point
/gps/pos/centre 0 0 0 cm
/gps/ang/type iso
/gps/ene/type Mono
/gps/ene/mono 2505 keV
When scoring dose deposition in a probe at a 30 cm distance from the source, i’m getting different results for each source definition. Around 30% difference between 2 and 3. And 300% between1 and 2.
Can anyone explain to me what could be the difference in each case? Excuse my limited background in Geant-4.
Thanks