The In situ Measurements of Particles and CME Transients (IMPACT)
investigation makes observations of plasma electrons, magnetic
fields and energetic particles using an array of seven instruments.

The Solar Wind Electron Analyzer (SWEA; UCB) consists of a boom-
mounted hemispherical top-hat electrostatic analyzer and measures
the distribution function of solar wind core and halo electrons from
below an eV to several keV, with high spectral and angular resolution
over virtually the full spherical range.

The Suprathermal Electron
Telescope (STE; UCB) consists of two arrays of silicon semiconductor
devices measuring ~2-20 keV electrons. The arrays look in opposite
directions with 80 x 80 deg fields of view.

MAG (GSFC) is a boom-mounted triaxial fluxgate magnetometer just inboard
of the SWEA and STE instruments.

The Solar Electron Proton Telescope (SEPT; ESTEC; U. Kiel) consists of two dual,
double-ended magnet/foil solid state
detector particle telescopes that separate and measure directional
fluxes of 20-400 keV electrons and 20-7000 keV protons.

The Supratherman Ion Telescope (SIT; GSFC, MPI, U.Maryland) is a
time-of-flight ion mass spectrometer that measures elemental
composition of He-Fe ions over the 30-2000 keV/n energy range.

The Low Energy Telescope (LET; Caltech, GSFC, JPL) is a double-
fan array of 14 solid state detectors that measures 1.5-13 MeV/n
protons and helium ions and 2-30 MeV/n heavier ions.

The High Energy Telescope (HET; Caltech, GSFC, JPL) is a linear array of six solid
state detectors that measures protons and helium ions up to 100 MeV/n
and electrons up to 5 MeV.

Further IMPACT detail is available in Luhmann et al, Sp. Sci. Rev. (2008) 136: 117-184 and immediately following instrument-specific papers.