Cosmic ray
The California High School Cosmic Ray Observatory, (abbreviated "CHICOS", for California HIgh school Cosmic ray ObServatory), operated by the Kellogg Laboratory at the California Institute of Technology in Pasadena, California, United States, is one of the world's largest ongoing Cosmic Ray observatory programs. It is known for its large network within the Los Angeles County area, based mainly on high school sites carrying cosmic ray detector units, though there are also detector units on associated elementary schools and middle schools.