1. Pedro Arce Introducción a GEANT4 1 GAMOS tutorial Plug-in’s Exercises Pedro Arce Dubois CIEMAT http://fismed.ciemat.es/GAMOS

2. Pedro Arce Introducción a GEANT4 2 Introduction This set of exercises are meant for a primer user to practice with each of the most common components usual 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 compiled in the previous examples

3. Pedro Arce Introducción a GEANT4 3 RT simulation Exercises Ex. 0: Installation Ex. 1: Basic example Ex. 2: More difficult geometry Generato r Ex. 3: Physics/cuts Ex. 4: User actions Ex. 5: Scoring Ex. 6: Sensitive detectors

4. Pedro Arce Introducción a GEANT4 4 Exercise 0: installation Download installation scripts from http://wwwae.ciemat.es/~arce/GAMOS/download/scripts. tgz http://wwwae.ciemat.es/~arce/GAMOS/download/scripts. tgz Uncompress it tar xvzf scripts.tgz Install it (under csh) cd scripts csh source installGamos.csh $HOME/gamos

5. Pedro Arce Introducción a GEANT4 5 Exercise 1: simple geometry 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

6. Pedro Arce Introducción a GEANT4 6 Exercise 1b: visualisation Visualize geometry and tracks OGLIX VRML2FILE DAWNFILE

7. Pedro Arce Introducción a GEANT4 7 Exercise 1c: use different e.m. physics Use low energy electromagnetic Use Penelope (Make statistics on processes/particles)

8. Pedro Arce Introducción a GEANT4 8 Exercise 2: more difficult geometry “Calorimeter” 1cm X 1cm X 5cm LSO crystals, placed along X axis LSO: Lu 76.4016%, Si 6.1328%, O 17.4656% 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 CO 2 (50%) Al (50%) Place at (50,0,0) cm

9. Pedro Arce Introducción a GEANT4 9 Exercise 2b: change generator position and direction Position of primary gammas at (-200,0,0) mm Direction along X axis

10. Pedro Arce Introducción a GEANT4 10 Exercise 2c: create C++ generator position distribution Create position distribution: Along a semicircunpherence 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

11. Pedro Arce Introducción a GEANT4 11 Exercise 3: Cuts by region Production cut 0.1 mm in crystals, 0.01 mm in tracker Limit step to 1 mm in crystals

12. Pedro Arce Introducción a GEANT4 12 Exercise 3b: Hadronic physics Primary particle: neutron 10 MeV Use QGSP_BERT_HP physics list Make it a plug-in

13. Pedro Arce Introducción a GEANT4 13 Exercise 4: 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…)

14. Pedro Arce Introducción a GEANT4 14 Exercise 4: User actions (II) For each event count the energy deposited in the crystal when the process that defined the step is ionisation Make an histogram of it

15. Pedro Arce Introducción a GEANT4 15 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

16. Pedro Arce Introducción a GEANT4 16 Exercise 6: Sensitive detector / hits Make the crystals and the tracker sensitive detectors Plot hits variables with GmHitsHistosUA Save hits in a file

17. Pedro Arce Introducción a GEANT4 17 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)

18. Pedro Arce Introducción a GEANT4 18 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