This experiment used two telescopes to measure the composition and energy spectra of solar (and galactic) particles above about 0.5 MeV/nucleon. The main telescope consisted of five collinear elements (three solid state, one CsI, and one sapphire Cerenkov) surrounded by a plastic anticoincidence shield. The telescope had a 60-deg, full-angle acceptance cone with its axis approximately normal to the spacecraft spin axis, permitting 8-sectored information on particle arrival direction. Four elements of the main telescope were pulse-height analyzed, and low- and high-gain modes could be selected by command to permit resolution of the elements H through Ni or of electrons and the isotopes of H, He, and light nuclei. A selection-priority scheme was included to permit sampling of less abundant particle species under normal and solar-flare conditions. The low-energy telescope was essentially a two-element, shielded, solid-state detector with a 70-deg, full-angle acceptance cone. The first element was pulse-height analyzed, and data were recorded by sectors. Data include the interplanetary region.

Instrument Overview
  ===================
    The charged particle detector had four measuring systems: two
    particle telescopes that operated in interplanetary space, and two
    that measured the intense trapped electrons and protons inside the
    Jovian radiation belts.
 
    During the interplanetary phase of the mission, before and after
    encounter with Jupiter, the experiment sought to identify the
    chemical elements hydrogen, helium, lithium, beryllium, boron,
    carbon, and nitrogen, and to separate hydrogen, deuterium, helium-3
    and helium-4 in an attempt to differentiate between particles coming
    from the Sun and those from the Galaxy. The instrument was also used
    to determine how the streams of high energy particles from the Sun
    travel through interplanetary space. The main telescope of seven
    solid-state detectors measured the composition of cosmic rays from 1
    to 500 million electron volts (MeV), and a three-element, low
    energy telescope measures 0.4 to 10 MeV protons and helium nuclei.
 
    Two types of sensors were used to cope with the extremely high
    intensities of trapped radiation in the magnetosphere of Jupiter. A
    solid-state electron current detector, operating below -40
    degrees C, was designed to detect those electrons above 3 MeV that
    generate the decimetric radio waves emitted from Jupiter. A trapped
    proton detector contains a foil of thorium which undergoes nuclear
    fission when impacted with protons above 30 MeV, but is insensitive
    to electrons.
 
  ['Instrument Overview' was adapted from FIMMELETAL p. 52.]

extracted metadata from PDS3 catalog and
                    modified to comply with PDS4 Information Model

Pioneer 11 Charged Particle Instrument

Description

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