Beta particle
An electron or positron which has been emitted by an atomic nucleus in a nuclear transformation. Most beta particles can be stopped by a few millimeters of aluminum or glass.
See: Decay
Glossary Source
JRC EU CBRNe Glossary
(
EU Glossary on Chemical, Biological, Radiological, Nuclear, and Explosive risks
)
https://publications.jrc.ec.europa.eu/repository/bitstream/JRC128863/JRC128863_01.pdf