RPR-31

Number of half-value layers

n = log2(1/B). How many HVLs a transmission B requires.

Reading speed

ShieldingHVL count

Governing equation

n=\log_2(1/B)

where

B: Transmission B (—)
n: Half-value layers (—)

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-31 — Number of half-value layers) is the form associated with HVL count. Working symbols: $B$ $\rightarrow$ $n$ . Ten HVLs is 10^{−3} transmission (because 2^{10} ≈ 10^3). Pair with HVL of the actual material and energy.

Purpose

Purpose: compute

n

from

B

in Radiation protection via

n=\log_2(1/B)

n = log2(1/B). How many HVLs a transmission B requires. 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

B = 0.010\,\mathrm{—}

, the governing relation

n=\log_2(1/B)

yields

n = 6.644\,\mathrm{—}

. A required B counted in doublings of attenuation. Move a slider: the numbers are this situation, not a canned story.

Calculator

Inputs

Transmission B B0.01 —

Outputs

Half-value layers n6.644 —

Reading speed

Watch on YouTube

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Narration of this film

A required B counted in doublings of attenuation.

Ten HVLs is 10^{−3} transmission (because 2^{10} ≈ 10^3). Pair with HVL of the actual material and energy.

Reading speed

Watch on YouTube