G0 experiment.Simulation.

G⁰ Simulation

2 types of simulations are required in this experiment. The first one is based on an exact calculation of the magnetic field and then allows a very precise determination of the proton trajectories. This is needed to precisely define the shape and the location of the detectors. We can use also this simulation to predict the contributions of the physical background (background reactions coming from the target). The second type of simulation uses the GEANT software from the CERN. It permits a very good and complete description of a particle passing through the matter. An exact field calculation is not possible in this simulation because of the computing time. The program will be used to simulate the neutral background (neutrons, gamma) which can interact with the detector.

The simulation without GEANT:
- Kinematics of G₀ experiment for the forward angles measurements.
- Impact of the trajectories in the focal plane (detector plane).

The simulation with GEANT:
- Get the simulation (last update the 11/01/2002), and read the README file.
- Comparison of GRAAL photoproduction and Orsay photoproduction and electroproduction
- Goals
- Forward angles measurement.
  - Generators and experimental measurement of background particles.
  - Results (counting rates and time of flight of particles).
  - Report on detected particles with a current of 1000 A in the magnet (postscript).
  - Report on detected particles with a current of 3500 A and 4000 A in the magnet. Calculation of asymmetries and errors (postscript).
  - Asymmetry calculations for 3 GeV at 5000 A and 4000 A and for 2.056 GeV at 4000 A (postscript).
  - Asymmetry calculations for 3 GeV at 4500 A (postscript).
- Back angles measurements.
  - Generators and experimental measurement of background particles.
  - Results (counting rates and time of flight of particles) for first version of geometry (g0-5a.euclid) with no Cerenkov and FPD at their nominal position (same results for LD2 target).
  - Results (counting rates and time of flight of particles) for the version 2 of geometry (g0-5b.euclid), with Cerenkov and FPD moved by 35 cm (downstream) from their nominal position (same results for LD2 target).
    Get the postscripts files for:
    LH2 rates for 424 MeV, 576 MeV, 799 MeV.
    LD2 rates for 424 MeV, 576 MeV, 799 MeV.
    Ratio upstream/downstream window of the target for pions at 424 MeV, 576 MeV, 799 MeV.
    And virtual/real ratio for pions and LD2 target at 424 MeV, 576 MeV, 799 MeV.

Simulation of the data stream with realistic Time Of Fligth using the results of Geant. Creation of coda files.