This page describes an image The discovery of positron
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Image caption:
This historic photograph shows the track of a positron moving through a cloud chamber from bottom to top. When a charged particle moves through a cloud chamber it leaves behind a line of condensation, making its path visible. Cloud chambers are normally build with magnetic fields. This curves the path of the charged particle, with the curve of the path giving more information about the properties of the particle.
Here we see the first positron (the antiparticle of an electron). A thick horizontal band in the middle is a lead plate in the cloud chamber that slowed the particle down, causing the positron's path to curve more sharply after crossing the plate. This image, taken in 1932, provided the first clear visual evidence of the positron.
The discovery of the positron confirmed that antimatter exists and opened an important field of research in modern physics.
Image credit: Carl D. Anderson Credit Link
Related glossary terms:
Antimatter
Image license: Public Domain Public Domain icons
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