RPR-16

Lead thickness from TVL

x = TVL log10(1/B). Lead (or concrete) needed for transmission B.

Reading speed

ShieldingLead thickness

Governing equation

x=\mathrm{TVL}\,\log_{10}(1/B)

where

TVL: Tenth-value layer (mm)
B: Required transmission (—)
x: Shield thickness (mm)
n: Number of TVLs (—)

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-16 — Lead thickness from TVL) is the form associated with Lead thickness. Working symbols: $TVL$ , $B$ $\rightarrow$ $x$ , $n$ . First TVL is larger than equilibrium TVL. Diagnostic lead: ~0.3–0.5 mm HVL at 80 kV; linac concrete: tens of cm.

Purpose

Purpose: compute

x

n

from

TVL

B

in Radiation protection via

x=\mathrm{TVL}\,\log_{10}(1/B)

x = TVL log10(1/B). Lead (or concrete) needed for transmission B. 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

TVL = 12.000\,\mathrm{mm}

B = 0.010\,\mathrm{—}

, the governing relation

x=\mathrm{TVL}\,\log_{10}(1/B)

yields

x = 24.00\,\mathrm{mm}

n = 2.00\,\mathrm{—}

. A required B and a stack of tenth-value sheets. Move a slider: the numbers are this situation, not a canned story.

Calculator

Inputs

Tenth-value layer TVL12 mmRequired transmission B0.01 —

Outputs

Shield thickness x24.00 mm
Number of TVLs n2.00 —

Reading speed

Watch on YouTube

Free library

Full library

Free PDF / open book

YouTube channels

00:0 / 00:08

Narration of this film

A required B and a stack of tenth-value sheets.

First TVL is larger than equilibrium TVL. Diagnostic lead: ~0.3–0.5 mm HVL at 80 kV; linac concrete: tens of cm.

Reading speed

Watch on YouTube