Inverse Square Law (Radiation)
Compute the radiation intensity at a new distance from a point source, I₂ = I₁·(d₁/d₂)², by the inverse square law: intensity falls with the square of distance. Doubling the distance reduces the dose to a quarter — which is why distance is one of the three basic radiation-protection defenses (time, distance and shielding) and the most effective and cheapest. Enter the initial intensity and distance and the new distance.
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Lei do inverso do quadrado (radiação)
Uma fonte pontual de radiação espalha sua energia em todas as direções, sobre a superfície de uma esfera que cresce com o quadrado do raio. Por isso a intensidade que chega a um ponto cai com o quadrado da distância: I₂ = I₁·(d₁/d₂)². A consequência é poderosa para a segurança: dobrar a distância reduz a dose a um quarto; triplicá-la, a um nono. É por isso que a distância é uma das três defesas clássicas da radioproteção — junto com tempo (menos exposição) e blindagem — e a mais barata e eficaz: afastar-se alguns metros de uma fonte, ou usar pinças e manipuladores longos, derruba a dose drasticamente sem gastar nada. (A lei vale rigorosamente para fontes pontuais no vácuo; fontes extensas ou meios absorvedores modificam um pouco a relação.) Informe a intensidade e a distância iniciais e a nova distância.
Related Tools
Radiation Shielding Attenuation
Compute the radiation intensity after passing through shielding, I = I₀·e^(−μ·x), by the exponential attenuation law, from the initial intensity (I₀), the material's linear attenuation coefficient (μ) and the thickness (x). Unlike alpha and beta particles (which have a finite range), gamma rays and X-rays are only exponentially attenuated — never fully blocked. It is the basis of shielding calculation. Enter the initial intensity, the attenuation coefficient and the thickness.
Gamma Exposure Rate
Compute the exposure (or dose) rate of a point gamma source, X = Γ·A/d², from the exposure-rate constant (Γ, specific to the radionuclide), the source activity (A) and the distance (d). It combines the source strength with the inverse square law, allowing you to estimate the dose received at a given distance — fundamental in planning tasks with radioactive sources. Enter the gamma constant, the activity and the distance.
Effective Dose
Compute the effective dose, E = H·wT, multiplying the equivalent dose in an organ (H, in mSv) by the tissue weighting factor (wT) reflecting the tissue's radiosensitivity. While the equivalent dose accounts for the radiation type, the effective dose weights the risk by the irradiated organ (gonads and marrow are more sensitive than skin or bone). It is the quantity used in occupational dose limits. Enter the equivalent dose and the tissue weighting factor.
The results provided by this tool are for general informational and educational purposes only and do not constitute professional, financial, medical, legal, tax or accounting advice. Always confirm important decisions with a qualified professional and official sources.