Geant4 radiation detector simulation
A Geant4 Monte Carlo study of 662 keV gamma transmission through lead and energy deposition in a sodium iodide detector.

Software compatibility
The C++ application and run files are prepared for Geant4 11.4.2 with pinned datasets. MCNP, FLUKA, and proprietary detector-simulation files are not included.
Project definition
Problem statement
Gamma transmission and detector response depend on photon energy, shielding thickness, detector geometry, material interactions, scoring rules, and the number of simulated histories.
Project objectives
- Build a NaI detector with an aluminium housing, lead shielding, air world, and axial gamma source.
- Simulate 662 keV photons with the FTFP_BERT_EMZ reference physics list.
- Score deposited energy, interaction position, detection efficiency, full-energy efficiency, and uncollided transmission.
- Estimate statistical uncertainty and demonstrate convergence from 1,000 to 100,000 histories.
- Compare simulated lead transmission at 1 mm, 5 mm, and 10 mm with NIST attenuation data.
Project structure
Project components
Geometry and materials
Defines detector, housing, shielding, world volumes, materials, and overlap checks.
Primary generator
Configures particle, energy, direction, position, and reproducible random seeds.
Physics configuration
Selects a documented reference physics list and production and tracking cuts.
Scoring
Records energy deposition, events, interactions, positions, and efficiency measures.
Analysis
Builds spectra, uncertainty, convergence, geometry, and reference comparisons.
Methodology
Project workflow
- 01Verify geometry
Materials, dimensions, placements, and overlap checks are confirmed.
- 02Run shielding cases
The unshielded, 1 mm, 5 mm, and 10 mm lead cases each use 100,000 photons.
- 03Score detector response
Energy deposition, detection, full-energy events, and uncollided transmission are recorded.
- 04Check statistics
The 5 mm case is repeated with 1,000, 10,000, and 100,000 histories.
- 05Validate results
Transmission is compared with NIST predictions and automatic acceptance checks are run.
Demonstration scenario
A 662 keV gamma beam passes through 0 mm, 1 mm, 5 mm, and 10 mm of lead before reaching a NaI detector. The study compares transmission, efficiency, deposited-energy spectra, NIST predictions, and uncertainty convergence.
Engineering
Tools and method
- Tools
- The project uses Geant4 11.4.2, C++, CMake, ROOT for subject analysis, simulation, and results.
- Environment
- Geant4 11.4.2 C++ project with CMake, pinned Geant4 datasets, and a reproducible Docker build.
- Simulation
- Documented geometry, 662 keV source, FTFP_BERT_EMZ physics list, scoring cuts, and fixed random seeds.
- Scoring
- Sequential event scoring records energy, counts, positions, detector efficiencies, and primary transmission.
- Verification
- Geometry overlap checks, NIST lead attenuation comparison, numerical tests, and event-count convergence.
Testing
Evaluation
Evaluation measures
- Geometry and material overlap checks
- Relative difference from NIST transmission predictions
- Detection and full-energy efficiencies
- Deposited-energy spectra for four shielding cases
- Binomial standard uncertainty
- Uncertainty scaling from 1,000 to 100,000 histories
Project boundaries
- Only Geant4 11.4.2 source and run files are delivered.
- The detector and electronics response are simplified and do not constitute instrument calibration.
- The project uses simulated sources and does not require handling radioactive materials.
- Medical, shielding, dose, laboratory, or regulatory decisions require qualified experts and validated models.
Included
- 01Geant4 detector geometry and material source code
- 02Primary-source, physics-list, scoring, and run modules
- 03Energy-deposition, efficiency, spectrum, and uncertainty plots
- 04Prepared macro files, benchmark cases, and results
- 05Complete project files, models, calculations, and analysis material in a private GitHub repository
- 06Complete project documentation in PDF and editable Word formats with synopsis, abstract, methodology, detector diagrams, Monte Carlo results, screenshots, and conclusion
- 07Setup and usage guide
Project record
No information is collected on this page.
- Permanent project ID
- GP-PH-0T3MW47
- Catalogued
- 22 Aug 2026
- Completed
- 22 Aug 2026
- Verified
- 22 Aug 2026
- Demonstration
- Included in repository
Handover
After purchase
- 01Payment is confirmed
The project is marked unavailable and cannot be purchased again.
- 02Repository access is granted
The buyer's submitted GitHub account receives access to the private repository.
- 03The purchase record is delivered
The certification sheet is prepared from the reviewed buyer details and sent privately by email.