Carl Anderson, Cloud Chamber photograph of a Positron

Carl Anderson, Cloud Chamber photograph of a Positron, 1932

Carl Anderson
1905 New York City, New York – 1991 San Marino, California
Cloud Chamber photograph of a Positron
1932
digital reproduction


Cloud chambers are used to detect charged particles, X-rays, and gamma rays which are not visible. These scientific devices contain water or alcohol and create vapor trails as subatomic particles pass through. Carl Anderson created this photograph of the first positron ever identified.

Positrons are subatomic particles with a positive charge and the same mass as negatively charged electrons. They are also known as anti-matter; almost identical to their matter counterparts, aside from their charge and spin direction. When antimatter like positrons and matter meet, they immediately annihilate into energy.