Radiation Shielding Calculator

Shielding Parameters

Shielding Equation:

I = I₀ × (d₀/d)² × 10^(−x/TVL)

Where:

  • I = Transmitted dose rate
  • I₀ = Dose rate at reference distance d₀
  • d₀ = Reference distance (1 m)
  • d = Distance from source
  • x = Shield thickness
  • TVL = Tenth-Value Layer (broad-beam, NCRP 151)

Note: TVL-based (10−x/TVL) and exponential (e−μx) forms are equivalent, related by TVL = ln(10)/μ ≈ 2.303/μ. They are alternatives — not multiplied together. Broad-beam TVLs already incorporate the build-up factor, so no separate build-up term is applied here.

Reference Standards:
• NCRP Report 151 (Megavoltage)
• NCRP Report 147 (Brachytherapy)
• AAPM Task Group Reports

Calculation Results

Dose Before Barrier:
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Transmission Factor:
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Dose After Barrier:
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Attenuation (TVLs):
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Material TVL:
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Side View Diagram

3.0 m 30 cm Measurement Point Source Concrete

Exponential Attenuation Curve