Photography in detectors

This cloud-chamber photograph, showing the track of a positively charged particle of electronic mass slowed down by passing upward through a lead plate, was among the earliest evidence of the existence of the positron adduced by C.D. Anderson (1932).

One of the first cloud chamber photographs showing the track of a cosmic ray. It was taken by Dmitry Skobeltzyn in his laboratory in Leningrad in the Soviet Union in 1927.

This photograph shows particle tracks in a cloud chamber. As charged particles pass through the supersaturated vapor in this chamber, they leave behind a visible trail of tiny droplets. Notice the pairs of curved trails that meet at the top of the image to form a curved, upside-down "v" shape. The curvature results from a magnetic field at right angles to the plane of the photograph, which bends the paths of charged particles into circular arcs.

September 21 st is Donald Glaser's birthday. Glaser is an American physicist and neurobiologist who was awarded the 1960 Nobel Prize in Physics for the invention of the bubble chamber. The bubble chamber is a detection device for particle physics that works on the same basic principle as the cloud chamber. A vessel is filled with a transparent liquid (usually liquid hydrogen) heated to just below its boiling point and aligned with a magnetic field. When the scientist is ready to take a reading, a piston is used to expand the chamber. This causes the liquid to become superheated. Any charged particles passing through the vessel will ionize the liquid and cause bubbles to appear along the particle's path. The bubble density and path shape can give information on the type, charge and lifetime of the particles.

FermilabFermilab's disused 15 foot diameter bubble chamber. Supposedly, Glaser was inspired by the bubbles in a glass of beer; however, in a 2006 talk, he refuted this story, saying that although beer was not the inspiration for the bubble chamber, he did experiments using beer to fill early prototypes. beer prototypes