Assertion: gamma ray | /r/Desires | 1 cm
Facets:
value: of lead
type: OTHER
value: to reduce their intensity
type: PURPOSE
Source sentences:
text: For example, gamma rays that require 1 cm (0.4″) of lead to reduce their intensity by 50% will also have their intensity reduced in half by 4.1 cm of granite rock, 6 cm (2½″) of concrete, or 9 cm (3½″) of packed soil.