Chicago Air Shower Array
Encyclopedia
The Chicago Air Shower Array (CASA) was a very large array of scintillation counters located in Utah
, fifty miles (80 kilometers) southwest of Salt Lake City
in Dugway Proving Grounds. CASA began operating in 1992, in coincidence with a second array, the Michigan Anti (MIA), under the name CASA-MIA. The array was made of 2500 square meters of buried muon
detectors. At the time of its completion, the CASA was the most sensitive experiment built to date in the study of gamma ray
and cosmic ray
interactions at energies above 100 TeV
(1014 electronvolt
s or 16 microjoules). Research topics on data from this experiment covered a wide variety of physics issues, including the search for gamma-rays from extragalactic sources (quasars and gamma-ray bursts), the study of diffuse gamma-ray emission from the Galactic plane, and a measurement of the cosmic ray composition in the poorly understood region from 100 to 100,000 TeV. The project was decommissioned sometime before the summer of 2001.
Utah
Utah is a state in the Western United States. It was the 45th state to join the Union, on January 4, 1896. Approximately 80% of Utah's 2,763,885 people live along the Wasatch Front, centering on Salt Lake City. This leaves vast expanses of the state nearly uninhabited, making the population the...
, fifty miles (80 kilometers) southwest of Salt Lake City
Salt Lake City, Utah
Salt Lake City is the capital and the most populous city of the U.S. state of Utah. The name of the city is often shortened to Salt Lake or SLC. With a population of 186,440 as of the 2010 Census, the city lies in the Salt Lake City metropolitan area, which has a total population of 1,124,197...
in Dugway Proving Grounds. CASA began operating in 1992, in coincidence with a second array, the Michigan Anti (MIA), under the name CASA-MIA. The array was made of 2500 square meters of buried muon
Muon
The muon |mu]] used to represent it) is an elementary particle similar to the electron, with a unitary negative electric charge and a spin of ½. Together with the electron, the tau, and the three neutrinos, it is classified as a lepton...
detectors. At the time of its completion, the CASA was the most sensitive experiment built to date in the study of gamma ray
Gamma ray
Gamma radiation, also known as gamma rays or hyphenated as gamma-rays and denoted as γ, is electromagnetic radiation of high frequency . Gamma rays are usually naturally produced on Earth by decay of high energy states in atomic nuclei...
and cosmic ray
Cosmic ray
Cosmic rays are energetic charged subatomic particles, originating from outer space. They may produce secondary particles that penetrate the Earth's atmosphere and surface. The term ray is historical as cosmic rays were thought to be electromagnetic radiation...
interactions at energies above 100 TeV
TEV
TEV may refer to:* TeV, or teraelectronvolt, a measure of energy* Total Enterprise Value, a financial measure* Total Economic Value, an economic measure* Tobacco etch virus, a plant pathogenic virus of the family Potyviridae....
(1014 electronvolt
Electronvolt
In physics, the electron volt is a unit of energy equal to approximately joule . By definition, it is equal to the amount of kinetic energy gained by a single unbound electron when it accelerates through an electric potential difference of one volt...
s or 16 microjoules). Research topics on data from this experiment covered a wide variety of physics issues, including the search for gamma-rays from extragalactic sources (quasars and gamma-ray bursts), the study of diffuse gamma-ray emission from the Galactic plane, and a measurement of the cosmic ray composition in the poorly understood region from 100 to 100,000 TeV. The project was decommissioned sometime before the summer of 2001.