Montecarlo method for geometric acceptance

This program evaluates the geometric acceptance of a flat disc-shaped detector using a Montecarlo method. The setup consists of:

• An emissive disc (the source), assumed to emit particles isotropically from each point on its surface.
• A detector disc, positioned above the source at a configurable height and horizontal offset.

The simulation models how many particles, emitted randomly from the source, successfully reach the detector, based purely on geometry and random numbers generation.

Features

• Fully configurable parameters:
  • Source radius
  • Detector radius
  • Detector height (distance above the source)
  • Horizontal offset of the detector
  • Number of simulated events
• Output includes full point data and detection hits for further analysis and plotting.

Compile and run

To compile the C simulation code, use:

gcc -o path/to/executable simulation.c -lm

You can replace gcc with any C compiler you prefer.

To run the simulation, use:

path/to/executable number_of_points source_radius detector_x detector_y detector_z detector_radius file_name

Arguments:

• number_of_points: total number of Montecarlo samples to simulate.
• source_radius: radius of the emissive disc (can be 0);
• detector_x, *_y, *_z: Coordinates of the center of the detector. *_z must be positive;
• detector_radius: radius of the detector disc (must be positive);
• output_file_name: name of the file where the output will be saved.

The the output is saved in the tmp directory as ./tmp/file_name.i.txt, where:

• i=1 contains the randomly generated source points and directions;
• i=2 contains the coordinates of starting and ending point that resulted in successful hits.

Dependencies

• A C compiler such as gcc;
• Python 3 for plotting
  • Required Python packages: matplotlib, numpy, mpl_toolkits.

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Other files

The old/ directory contains legacy .c files used for testing simplified scenarios (e.g. no offset or point-like sources). These are provided for reference only and are not part of the main simulation.