For immediate release US and Japanese physicists are cooperating in a research project which aims to fly balloon-borne cosmic ray detectors around the South Pole from McMurdo Station, Antarctica. A research balloon carrying an unmanned scientific gondola was launched from Williams Field, near McMurdo Station, on 22 December 1994. The balloon flew above 120,000 feet, and took over 300 hours to go completely around Antarctica and return to the vicinity of the launch site. Balloon flight operations are being performed by the NASA-operated National Scientific Balloon Facility, in collaboration with the US National Science Foundation, which operates all Antarctic research programs. The scientific payload was prepared and will be analyzed by a team of physicists from all participating institutions.
Cosmic rays are radiation reaching the earth from outer space.
Cosmic ray measurements must be performed via balloon or space flights because of the shielding effect of the earth's atmosphere. The intensity of cosmic radiation is very weak, comparable to starlight in terms of the amount of energy striking the earth. Thus long exposures of large detectors are required to obtain a significant measurement. The photographic emulsion material is similar to that used in making black and white film, but has been supersensitized to record the tracks of individual subatomic particles. The photographic plates are used to record the tracks of incoming cosmic ray particles, and also the tracks of secondary particles produced when the cosmic rays collide with a nucleus in the detector itself.