Principal Investigator: R.E. Vogt
The following section on instrumentation has been extracted from the NSSDC documentation for the Voyager Cosmic Ray Subsystem (Reference_ID = NSSDCCRS1979).
As its name implies, the Cosmic Ray Subsystem (CRS) was designed for cosmic ray studies [STONEETAL1977B]. It consists of two high Energy Telescopes (HET), four Low Energy Telescopes (LET) and The Electron Telescope (TET).
The detectors have large geometric factors (~ 0.48 to 8 cm^2 ster) and long electronic time constants (~ 24 [micro]sec) for low power consumption and good stability.
Normally, the data are primarily derived from comprehensive ([Delta]E, [Delta]E and E) pulse- height information about individual events. Because of the high particle fluxes encountered at Jupiter and Saturn, greater reliance had to be placed on counting rates in single detectors and various coincidence rates. In interplanetary space, guard counters are placed in anticoincidence with the primary detectors to reduce the background from high-energy particles penetrating through the sides of the telescopes. These guard counters were turned off in the Jovian magnetosphere when the accidental anticoincidence rate became high enough to block a substantial fraction of the desired counts. Fortunately, under these conditions the spectra were sufficiently soft that the background, due to penetrating particles, was small.
The data on proton and ion fluxes at Jupiter were obtained with the LET. The thicknesses of individual solid-state detectors in the LET and their trigger thresholds were chosen such that, even in the Jovian magnetosphere, electrons made, at most, a very minor contribution to the proton counting rates [LUPTON&STONE1972]. Dead time corrections and accidental coincidences were small (< 20%) throughout most of the magnetotail, but were substantial (> 50%) at flux maxima within 40 R[J] Of Jupiter. Data have been included in this package for those periods when the corrections are less than ~ 50% and can be corrected by the user with the dead time appropriate to the detector (2 to 25 [micro]sec). The high counting rates, however, caused some baseline shift which may have rais