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Cosmic Ray Detectors

NSSDCA ID: 1964-078C-04

Mission Name: Zond 2
Principal Investigator:Prof. S. N. Vernov


Zond 2 carried Cosmic Ray Detectors designed to record the cosmic radiation intensity and its variation at the Earth, in space as distance from the Sun increased, and at Mars. The apparatus consisted of two scintillation counters and two gas-discharge proportional counters.

One of the scintillation counters was housed inside the station and was based on a cylindrical NaI crystal 2 cm in diameter and 2 cm high. The counter measured the total ionization produced by radiation in the crystal and counted the number of times the energy release was above 30 keV and above 2.5 MeV. The second scintillation counter was mounted on the outside of the station. This counter had a cylindrical CsI crystal 2.0 cm in diameter and 0.3 cm high. On the side facing free space over a solid angle of about 3 steradians the crystal was covered with thin aluminum foil (2.2 mg/square cm). In the other direction the crystal and photomultiplier were covered with 1 g/square cm thick aluminum. The counter tracked particles which released an energy over 30 keV (electrons with energy over 70-80 keV or protons with energy over about 500 keV).

The two gas-discharge counters (sometimes referred to as Geiger counters) were mounted inside the stations. They were unshielded self-quenched halogen STS-5 counters with a filament anode, with a working length of 5.0 cm and a diameter of 1.0 cm. The tubes were filled with neon and 5% bromine, with a small amount of argon. The tube casings (cathodes) were made of thin steel (0.05 g/square cm) with stiffeners to provide mechanical strength. The energy required to pass through the casing was about 0.5 MeV for electrons and 5 MeV for protons.

Shielding from the spacecraft itself amounted to about 10 to 100 g/square cm. The STS-5 counters averaged 5.62 pulses per second per square cm over the period from December 1 through 25, with only a 4% variation in the daily averages.

Alternate Names

  • Zond2/CosmicRayDetectors


  • Space Physics: Magnetospheric Studies

Additional Information

Questions and comments about this experiment can be directed to: Dr. David R. Williams



NameRoleOriginal AffiliationE-mail
Prof. S. N. VernovPrincipal InvestigatorMoscow State University
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