1. GAMOS tutorial Plug-in’s Exercises
Pedro Arce Dubois
CIEMAT
Pedro Arce
Introducción a GEANT4

2. Introduction Introducción a GEANT4 Pedro Arce
This set of exercises are meant for a primer user to practice with each of the most common components used in the simulation of detectors
Geometry
Visualisation
Primary generator
Electromagnetic/hadronic physics
Production cuts and user limits
Scoring
Sensitive detectors
They represent examples on
How to do simulation using GAMOS commands
How to extend GAMOS adding new C++ code
They are sequential
Use the commands of the previous exercise (only change what indicated)
Some examples use code that is compiled in the previous examples
Pedro Arce
Introducción a GEANT4

3. RT simulation Exercises
Ex. 1: Basic example
Ex. 2: More difficult geometry
Generator
Ex. 3: Physics/cuts
Ex. 4: User actions
Ex. 5: Scoring
Ex. 6: Sensitive detectors
Pedro Arce
Introducción a GEANT4

4. Exercise 1: simple geometry
Tube radius 100cm length 200cm of Water
inside Box 30cm X 30cm X 40cm of Aluminun
Standard electromagnetic physics
Primary particle: gamma 10 MeV at (0,0,0) in random direction
Pedro Arce
Introducción a GEANT4

5. Exercise 1b: visualisation
Visualize geometry and tracks
OGLIX
VRML2FILE
DAWNFILE
Pedro Arce
Introducción a GEANT4

6. Exercise 1c: use different e.m. physics
Use low energy electromagnetic
Use Penelope
(Make statistics on processes/particles)
Pedro Arce
Introducción a GEANT4

7. Exercise 2: more difficult geometry
“Calorimeter”
1cm X 1cm X 5cm LSO crystals, placed along X axis
LSO: Lu %, Si %, O %
Block of 4X4 crystals
Place three crystal blocks at (5,-5,0), (5,0,0), (5,5,0) cm
“Tracker”
Box 40cm X 20cm X 20cm of CO2 (50%) Al (50%)
Place at (50,0,0) cm
Pedro Arce
Introducción a GEANT4

8. Exercise 2b: change generator position and direction
Position of primary gammas at (-200,0,0) mm
Direction along X axis
Pedro Arce
Introducción a GEANT4

9. Exercise 2c: create C++ generator position distribution
Create position distribution:
Along a semicircumpherence of radius 1 cm in YZ plane, centered in (0,0,0)
Change radius at the input script
Make it a plug-in and select it at the input script
Pedro Arce
Introducción a GEANT4

10. Exercise 3: Cuts by region
Production cut 0.1 mm in crystals, 0.01 mm in tracker
Limit step to 1 mm in crystals
Pedro Arce
Introducción a GEANT4

11. Exercise 3b: Change physics list
Primary particle: gamma 10 MeV
Use new physics list: eScatteringPhysicsList
Make it a plug-in
Pedro Arce
Introducción a GEANT4

12. Exercise 4a: User actions
Kill event if primary particle does not leave all its energy in crystal
If it exits the crystals
(it might exit and enter back and leave some energy in the meantime…)
Pedro Arce
Introducción a GEANT4

13. Exercise 4b: User actions
For each event count the energy deposited in the crystal when the process that defined the step is ionisation
Make an histogram of it
Pedro Arce
Introducción a GEANT4

14. Exercise 5: Scoring
Count number of secondaries with energy > 100 keV produced in the crystals per event
Count energy deposited in the tracker per event
Pedro Arce
Introducción a GEANT4

15. Exercise 6: Sensitive detector / hits
Make the crystals and the tracker sensitive detectors
Plot hits variables with GmHitsHistosUA
Save hits in a file
Pedro Arce
Introducción a GEANT4

16. Exercise 6b: Study detector effects
Use as primary particle F18 at position (50,0,0)mm with 1 miliCurie
Make energy resolution of crystals 20% and tracker 2%
Make measuring time 1 milisecond for both SD
Make dead time 1 milisecond for both SD
(look for number of hits and good hits in hits.root/hits.csv)
Make dead time 10 nanoseconds for both SD
Make energy resolution of crystals 0% and tracker 0%
(look at hits output file)
Pedro Arce
Introducción a GEANT4

17. Exercise 6c: Create SD with C++
Assign Sensitive Detector to crystals
Create hits with:
Track ID
Deposited energy
Position
Print number of hits in each event
Print Track ID, deposited energy and position of each hit
Pedro Arce
Introducción a GEANT4