Simulation of germanium detector calibration using the Monte Carlo method: comparison between point and surface...

Area of Science:

• Nuclear instrumentation and measurement
• Computational physics

Background:

• Detector calibration is crucial for accurate measurements.
• Monte Carlo simulations, specifically using the MCNP code, offer a convenient approach for detector calibration.
• Previous simulations using a point source model showed discrepancies with experimental data.

Purpose of the Study:

• To compare the accuracy of point and surface source models in MCNP simulations for detector calibration.
• To investigate the impact of collimator diameter and detector-source distance on simulation accuracy.
• To validate simulation results against laboratory measurements using a disc-shaped standard source.

Main Methods:

• Simulated a disc-shaped standard source using both point and surface source models in MCNP.
• Compared simulation results with laboratory measurements.
• Analyzed the influence of collimator diameter and detector-source distance on the discrepancies between models and experiments.

Main Results:

• The surface source model demonstrated improved accuracy compared to the point source model, aligning better with experimental measurements.
• The point source model provided acceptable results for large collimator diameters and increased detector-source distances.
• A surface source model was necessary for accurate simulations with smaller collimator diameters and shorter detector-source distances.

Conclusions:

• The choice of source model in Monte Carlo simulations significantly impacts detector calibration accuracy.
• Surface source models are recommended for scenarios involving small collimators and short source-detector distances.
• Point source models can be sufficient under specific conditions of larger collimators and greater distances, offering computational efficiency.