Radioactive Decay Calculator
Calculate the remaining quantity of a radioactive substance after a given time period using the exponential decay formula: N(t) = N₀ × e^(-λt)
atoms/grams/moles
s⁻¹
Results:
Remaining Quantity:
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Percentage Remaining:
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Quantity Decayed:
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Half-Life Calculator
Calculate half-life, decay constant, or remaining quantity using the relationship: t₁/₂ = ln(2)/λ = 0.693/λ
Results:
Remaining Quantity:
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Number of Half-Lives:
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Decay Constant:
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Activity Unit Converter
Convert between different radioactivity units: Becquerel (Bq), Curie (Ci), and their multiples
Conversion Result:
Enter values and click convert
Common Conversions:
| 1 Ci | = | 3.7 × 10¹⁰ Bq |
| 1 mCi | = | 3.7 × 10⁷ Bq |
| 1 μCi | = | 3.7 × 10⁴ Bq |
| 1 GBq | = | 27.03 mCi |
Radiation Dose Calculator
Calculate absorbed dose, equivalent dose, and effective dose using standard radiation protection formulas
Dose Calculations:
Dose Rate:
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Total Dose:
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Equivalent Dose:
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Safety Reference:
- Annual limit for radiation workers: 20 mSv/year
- Annual limit for general public: 1 mSv/year
- Natural background radiation: ~2-3 mSv/year
Decay Constant Calculator
Calculate decay constant (λ), mean lifetime (τ), and related parameters using fundamental relationships
u (atomic mass units)
Calculated Parameters:
Decay Constant (λ):
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Mean Lifetime (τ):
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Initial Activity (A₀):
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Specific Activity:
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Key Formulas:
- λ = ln(2) / t₁/₂ = 0.693 / t₁/₂
- τ = 1 / λ = t₁/₂ / ln(2)
- A₀ = λ × N₀
- N(t) = N₀ × e^(-λt)
Distance & Inverse Square
Calculate the dose rate at a given distance from a point source
Dose Rate Calculation:
Dose Rate:
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Shielding Calculator
Calculate the reduction in dose rate due to shielding material
Reduced Dose Rate:
Reduced Dose Rate:
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Unit Conversions
Common Radioactive Materials
| Isotope | Half-Life | Radiation | Energy (MeV) | Uses |
|---|---|---|---|---|
| Cobalt-60 | 5.27 years | Gamma | 1.17, 1.33 | Radiotherapy, Industrial Radiography |
| Cesium-137 | 30.1 years | Gamma | 0.662 | Level Gauges, Brachytherapy |
| Iodine-131 | 8 days | Beta, Gamma | 0.364 | Thyroid Treatment |
| Technetium-99m | 6 hours | Gamma | 0.140 | Medical Imaging (SPECT) |
| Am-241 | 432 years | Alpha, Gamma | 0.0595 | Smoke Detectors |