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RPR-04

ICRP neutron wR(E)

wR(E) from ICRP 103. Photons and electrons are 1; α is 20.

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QuantitiesICRP 103 wR

Governing equation

wR(E)=2.5+18.2 e−(ln⁡E)2/6 (E<1 MeV)w_R(E)=2.5+18.2\,e^{-(\ln E)^2/6}\ (E<1\,\mathrm{MeV})

E∈[0.01,200]E \in \left[0.01, 200\right]

where

E
Neutron energy (MeV)
w_R
Radiation weighting factor (—)

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RPR-04 · spectrum
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①

Governing law — red

wR(E)=2.5+18.2 e−(ln⁡E)2/6 (E<1 MeV)w_R(E)=2.5+18.2\,e^{-(\ln E)^2/6}\ (E<1\,\mathrm{MeV})

E∈[0.01,200]E \in \left[0.01, 200\right]

E=0.01E = 0.01wR=3.031w_R = 3.031

②

Domain of the variable — blue

Emin⁡=0.01,Emax⁡=200E_{\min} = 0.01,\quad E_{\max} = 200

E∈[0.01,200]E \in \left[0.01, 200\right]

E=0.01E = 0.01E=0.01E = 0.01

③

Response curve — green

wR(E)=2.5+18.2 e−(ln⁡E)2/6 (E<1 MeV)w_R(E)=2.5+18.2\,e^{-(\ln E)^2/6}\ (E<1\,\mathrm{MeV})

E∈[0.01,200]E \in \left[0.01, 200\right]

E=0.01E = 0.01wR=3.031w_R = 3.031

④

Rate of change — amber

dwRdE\frac{\mathrm{d}w_R}{\mathrm{d}E}

E∈[0.01,200]E \in \left[0.01, 200\right]

E=1.268E = 1.268wR′=5.147w_R^{\prime} = 5.147

Lecture brief

Historical brief

Inverse-square, half-value layer, ICRP weighting and ALARA are the protection craft since the 1920s commissions. The lab computes transmission, equivalent dose and a shielding snapshot. This sheet (RPR-04 — ICRP neutron wR(E)) is the form associated with ICRP 103 wR. Working symbols: EE →\rightarrow wRw_R. A continuous log-Gaussian in neutron energy. Peak wR sits near 1 MeV.

Purpose

Purpose: compute wRw_R from EE in Radiation protection via wR(E)=2.5+18.2 e−(ln⁡E)2/6 (E<1 MeV)w_R(E)=2.5+18.2\,e^{-(\ln E)^2/6}\ (E<1\,\mathrm{MeV}) wR(E) from ICRP 103. Photons and electrons are 1; α is 20. Use it when a real radiation protection question must be answered in SI before a code check.

Live realistic example

In symbols

Live case. Given E=1.000 MeVE = 1.000\,\mathrm{MeV}, the governing relation wR(E)=2.5+18.2 e−(ln⁡E)2/6 (E<1 MeV)w_R(E)=2.5+18.2\,e^{-(\ln E)^2/6}\ (E<1\,\mathrm{MeV}) yields wR=20.69 —w_R = 20.69\,\mathrm{—}. A neutron energy slider and a wR bar. Move a slider: the numbers are this situation, not a canned story.

Calculator

Inputs

Outputs

  • Radiation weighting factor w_R20.69 —
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RPR-04 · spectrum
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Narration of this film

A neutron energy slider and a wR bar.

A continuous log-Gaussian in neutron energy. Peak wR sits near 1 MeV.

Reading speed

Watch on YouTube