Home > Program > Session 2 > Hands-on

Hands-on

Code for download: session2_start.tar.gz

To get the environment setup called automatically when a new terminal is open, you can add the commands for this setting in your login script, for example in $HOME/.bash_profile file if bash is your default shell. Open this file in your editor and add the following lines:

# Geant4 environment
source /nfsapp/physics/geant4.bash -n

Hands-on 2a:

The picture shows geometry which will be implemented in this session.

Inspect the code of the geometry already implemented and modify materials to correspond to the geometry description below. The code already present describes the geometry of the first arm detector.
- Identify the code used for printing all materials.
Add following materials (using NIST manager):
- Argon gas (G4_Ar), CsI (G4_CESIUM_IODIDE) and Copper (G4_Cu)
- and update the materials in the First Arm detector according to the geometry description below
Implement the geometry of the second arm described below.
- Get inspired by the code already present
- Proceed step by step. After adding each piece of geometry (solid, logical volume and its placement(s)), recompile and test your application with visualization.
- Note that the Second Arm detector has similar components as the First Arm detector but not same.
Check your geometry with the geometry scene tree browser

Geometry to be implemented:

Extend Second arm detector with:
- EM calorimeter (in yellow colour)
  - of a box shape with hx=1.5*m, hy=30.*cm, hz=15.*cm
  - of CsI material
  - placed at 2*m in z-direction from the center of its parent volume (Second Arm Detector).
- Fill the EM calorimeter with 15*cm layers along x-direction of the same material (CsI)

Geometry already implemented, to be updated:

Material Air defined using NIST manager (the remaining materials have to be added and assigned to the volumes )
World volume
- represented as a box of hx=10.*m, hy=3.*m, hz=10.*m
- of Air material
Tube volume
- of a tube shape with rmin = 0.*m, rmax=1.*m, hz=1.*m
- of Air material
First arm detector:
- represented as a box of hx=1.5*m, hy=1.0*m, hz=3.0*m
- of Air material
- placed in -5.*m in z-direction (in front of Tube (in blue colour).)
- including:
  1. 5 Drift chambers (in green colour)
    - of a box shape with hx=1.*m, hy=30.*cm, hz=1.*cm
    - of Air material to be changed to Argon gas
    - placed along z-axis with a distance of 0.5*m from each other with the middle one in the center of the parent volume
  2. Wire plane
    - of a box shape with hx=1.*m, hy=30.*cm, hz=0.1*mm
    - of Air material to be changed to Copper
    - placed inside each drift chamber in its center.
Second arm detector
- represented as a box of hx=1.5*m, hy=1.*m, hz=3.*m
- of Air material
- placed in 5.*m in z-direction (behind Tube (in blue colour)).
- Including:
  1. 5 Drift chambers (in green colour)
    - of a box shape with hx=1.5*m, hy=30.*cm, hz=1.*cm
    - of Air material to be changed to Argon gas material
    - placed along z-axis with a distance of 0.5*m from each other with the middle one in the center of the parent volume.
  2. Wire plane
    - of a box shape with hx=1.5*m, hy=30.*cm, hz=0.1*mm
    - of Air material to be changed to Copper material
    - placed inside each drift chamber in its center

Hands-on 2b:

Explore provided macros init_vis.mac and run.mac. Run the application exampleED in batch mode (using a provided macro).
Explore implemented geometry:
- Add visualization attributes for added volumes in vis.mac macro file
  - Tips : First change the color with the scene tree browser and look in the output for the command name
- Add axes on your scene to check your geometry (use Qt User Interface Help widget)