Shielding Help
What this calculator does
HPCalc shielding estimates photon shielding using narrow-beam exponential attenuation (single slab, μ per cm, thickness in cm) to support transmission, dose-rate scaling, HVL/TVL, and target-thickness questions.
It supports bundled tabulated linear attenuation coefficients (μ) and an audited custom μ override workflow with structured documentation fields for exports.
What this calculator does not do
- No buildup factor model.
- No scatter correction or broad-beam geometry treatment.
- No workload, occupancy, or use-factor engine.
- No skyshine, duct, or leakage path modeling.
- No formal structural shielding design certification or code check.
Core concepts
- HVL: thickness that reduces intensity to 50%.
- TVL: thickness that reduces intensity to 10%.
- Target transmission thickness: thickness required to reach a selected transmission fraction.
- Target dose-rate thickness: thickness needed to reduce from initial to target dose rate.
- Material comparison: side-by-side μ/HVL/TVL screening values for selected energy/tolerance.
Custom μ workflow
When you use custom μ, HPCalc requires source type, override reason, and source note before report export.
Optional reference IDs should be slug-like identifiers so provenance stays structured.
Confidence labels and report/export behavior
Tabulated μ rows carry confidence metadata; custom μ requires source type, override reason, and source note before JSON/Markdown export succeeds.
Reports include assumptions, warnings, references, and the screening disclaimer. If validation fails or required audit fields are missing, export actions stay blocked until you fix the issues shown in the UI.
Common mistakes
- Using a μ value at mismatched photon energy without documenting the mismatch.
- Treating narrow-beam screening outputs as final facility design values.
- Skipping custom μ provenance fields, which blocks report export.
Professional judgment required