RAD-34

Collision stopping snapshot

Bethe log term.

Reading speed

Radiationstopping

Governing equation

S_{\mathrm{col}}\propto Z/(\beta^2 A)\ln(2m_e c^2\beta^2/I)

where

Z: Z (—)
A: A (—)
\beta: β (—)
I: I (eV)
S: S/ρ (MeV cm²/g)

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-34 — Collision stopping snapshot) is the form associated with stopping. Working symbols: $Z$ , $A$ , $\beta$ , $I$ $\rightarrow$ $S$ . Bethe log term.

Purpose

Purpose: compute

S

from

Z

A

\beta

I

in Radiation physics via

S_{\mathrm{col}}\propto Z/(\beta^2 A)\ln(2m_e c^2\beta^2/I)

Bethe log term. 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

Z = 6.000\,\mathrm{—}

A = 12.000\,\mathrm{—}

\beta = 0.500\,\mathrm{—}

I = 80.000\,\mathrm{eV}

, the governing relation

S_{\mathrm{col}}\propto Z/(\beta^2 A)\ln(2m_e c^2\beta^2/I)

yields

S = 5.131\,\mathrm{MeV cm^{2}/g}

. Bethe log term. Move a slider: the numbers are this situation, not a canned story.

Calculator

Inputs

Z Z6 —A A12 —β \beta0.5 —I I80 eV

Outputs

S/ρ S5.131 MeV cm²/g

Reading speed

Watch on YouTube

Free library

Full library

Free PDF / open book

YouTube channels

00:0 / 00:08

Narration of this film

Bethe log term.

Reading speed

Watch on YouTube