a. For detailed radiation transport calculations, the following shall be done:
1. Use for the calculation the characteristics of the actual materials used in the final structure or subsystem, or by agreement with the customer alternative materials that have similar electromagnetic (electron-photon) and nuclear cross-sections.
NOTE Detailed radiation “transport” calculations provide a more accurate treatment of the radiation interaction processes in which the particle numbers, species, energy, and direction of propagation can change in a complex manner according to the Boltzmann transport equation. This type of calculation approach is used where aspects of the equipment or component performance and the influence of shielding cannot be adequately treated within a sector shielding analysis.
2. If undertaken, agree with the customer the level of physics simulation to use.
NOTE The objective is to ensure accurate treatment of the production of secondary particles which can affect the component, system or human, as well as the attenuation and scattering of the primary radiation (see ECSS-E-HB-10-12 Section 5.6).
3. Agree with the customer the number of dimensions (1-D. 2-D or 3‑D) to use in the simulation.
NOTE The objective is to ensure that geometries are well represented and the analysis is conservative.
4. Use a number of primary particle simulations such that the statistical errors for the results used to infer component response are within the project’s design margins for the radiation shielding model.
NOTE
Radiation simulations employing