Data Set Overview
=================
 
    A wide range of ion species and velocity
    distributions are expected to be found as the Giotto
    spacecraft traverses the coma of Halley's Comet.  The
    outer coma is characterized by the interaction
    between solar wind and cometary plasmas, the inner
    coma by the outflow of cometary neutrals and their
    ionization products.  The resultant demands on
    instrument dynamic range preclude use of a single
    sensor for measurements of ion composition.  The
    Giotto Ion Mass Spectrometer (IMS) therefore consists
    of two sensors: one optimized for the outer and the
    other for the inner coma, with each obtaining
    complementary information in the region for which it
    is not optimized.  Both sensors feature mass imaging
    characteristics, thereby permitting simultaneous
    measurements of several ion species by means of
    multi-detector arrays.  The High Intensity
    Spectrometer (HIS) was designed to complement the
    HERS in the inner coma.
 
 
    Sampling Parameter Name        : TIME
    Sampling Parameter Resolution  : 8.0
    Minimum Available Sampling Int : 4.0
    Sampling Parameter Unit        : SECOND
    Data Set Parameter Name        : COUNTS
    Data Set Parameter Unit        : SEC**-1