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Index/Radiation physics/RAD-33

RAD-33

Bragg–Gray

Cavity to medium.

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RadiationBragg–Gray

Governing equation

Dw=Dg(S/ρ)wgD_w=D_g(S/\rho)_w^g

Dg∈[1×10−4,1]D_g \in \left[1\times 10^{-4}, 1\right]

where

D_g
Gas dose (Gy)
(S/\rho)_w^g
Stopping ratio (—)
D_w
Water dose (Gy)

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RAD-33 · dose
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①

Governing law — red

Dw=Dg(S/ρ)wgD_w=D_g(S/\rho)_w^g

Dg∈[1×10−4,1]D_g \in \left[1\times 10^{-4}, 1\right]

Dg=1×10−4D_g = 1\times 10^{-4}Dw=1.13×10−4D_w = 1.13\times 10^{-4}

②

Domain of the variable — blue

D_g_{\min} = 1\times 10^{-4},\quad D_g_{\max} = 1

Dg∈[1×10−4,1]D_g \in \left[1\times 10^{-4}, 1\right]

Dg=1×10−4D_g = 1\times 10^{-4}Dg=1×10−4D_g = 1\times 10^{-4}

③

Response curve — green

Dw=Dg(S/ρ)wgD_w=D_g(S/\rho)_w^g

Dg∈[1×10−4,1]D_g \in \left[1\times 10^{-4}, 1\right]

Dg=1×10−4D_g = 1\times 10^{-4}Dw=1.13×10−4D_w = 1.13\times 10^{-4}

④

Rate of change — amber

dDwdDg\frac{\mathrm{d}D_w}{\mathrm{d}D_g}

Dg∈[1×10−4,1]D_g \in \left[1\times 10^{-4}, 1\right]

Dg=0.006D_g = 0.006Dw′=1.13D_w^{\prime} = 1.13

Lecture brief

Historical brief

Beer attenuation, Compton (1923), Klein–Nishina, Bragg–Gray cavity and KERMA are the transport of photons and charged particles in matter. The sheets compute fluence, kerma and stopping. This sheet (RAD-33 — Bragg–Gray) is the form associated with Bragg–Gray. Working symbols: DgD_g, (S/ρ)wg(S/\rho)_w^g →\rightarrow DwD_w. Cavity to medium.

Purpose

Purpose: compute DwD_w from DgD_g, (S/ρ)wg(S/\rho)_w^g in Radiation physics via Dw=Dg(S/ρ)wgD_w=D_g(S/\rho)_w^g Cavity to medium. Use it when a real radiation physics question must be answered in SI before a code check.

Live realistic example

In symbols

Live case. Given Dg=0.010 GyD_g = 0.010\,\mathrm{Gy}, (S/ρ)wg=1.130 —(S/\rho)_w^g = 1.130\,\mathrm{—}, the governing relation Dw=Dg(S/ρ)wgD_w=D_g(S/\rho)_w^g yields Dw=0.01130 GyD_w = 0.01130\,\mathrm{Gy}. Cavity to medium. Move a slider: the numbers are this situation, not a canned story.

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Inputs

Outputs

  • Water dose D_w0.01130 Gy
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RAD-33 · dose
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Narration of this film

Cavity to medium.

Cavity to medium.

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