Development of a chemical code applicable to ions based on the PHITS code for efficient and visual radiolysis
Yusuke Matsuya1,2, Yuji Yoshii3, Tamon Kusumoto4
1Nuclear Science and Engineering Center, Japan Atomic Energy Agency, 2-4 Shirane Shirakata, Tokai, Ibaraki 319-1195, Japan.
Physical Chemistry Chemical Physics : PCCP
|March 21, 2025
Summary
This study enhances the PHITS-Chem code for faster water radiolysis simulations, improving the calculation of species yields (G values) for various ion beams. The optimized code provides accurate, visualized insights into radiation biology and ion-beam radiotherapy.
Area of Science:
- * Radiation chemistry and physics
- * Computational modeling of biological systems
- * Medical physics and radiotherapy
Background:
- * Water radiolysis is crucial for understanding radiation-induced biological effects, including DNA damage and carcinogenesis.
- * Existing Monte Carlo simulation codes for water radiolysis are computationally intensive and limited to specific ion types.
- * The Particle and Heavy Ion Transport code System (PHITS) previously included a chemical code (PHITS-Chem) for electron radiolysis.
Purpose of the Study:
- * To enhance the PHITS-Chem code to support a wider range of ion beam species.
- * To significantly reduce computational time for water radiolysis simulations.
- * To maintain and validate the accuracy of the simulation results.
Main Methods:
- * Developed an updated PHITS-Chem code supporting diverse ion beam species.
- * Implemented a space partitioning method to improve reaction detection efficiency.
- * Incorporated a radical scavenger model to shorten OH radical lifetimes.
- * Benchmarked the code using protons, alpha particles, and carbon ions against literature data.
- * Integrated 4D visualization capabilities with PHIG-3D software.
Main Results:
- * The enhanced PHITS-Chem code achieved an approximate 28-fold reduction in computation time for G value calculations under 1-MeV electron exposure.
- * Calculation accuracy was maintained despite the significant speed improvement.
- * The code successfully simulated radiolysis for protons, alpha particles, and carbon ions.
- * Demonstrated the capability to handle specific OH radical scavengers like tris(hydroxymethyl)aminomethane and dimethyl sulfoxide.
Conclusions:
- * The updated PHITS-Chem code offers a computationally efficient and accurate tool for simulating water radiolysis across various ion beams.
- * Its 4D visualization feature provides intuitive insights into radiation-induced chemical species.
- * The code is expected to advance the understanding of biological effects in ion-beam radiotherapy.
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