The Particle Environment Monitor (PEM) on NASA's Upper Atmosphere
Research Satellite (UARS) measures the type, amount, energy, and
distribution of charged particles injected into the Earth's
thermosphere, mesosphere, and stratosphere. PEM consists of four
instruments: the ... Atmospheric X-Ray Imaging Spectrometer (AXIS),
the High Energy Particle Spectrometer (HEPS), the Medium Energy
Spectrometer (MEPS), and the Vector Magnetometer (VMAG).
The UARS PEM level 2 HEPSB daily product (UARPE2HEPSB) contains
the electron high-resolution spectral data converted to number
intensity units from the HEPS telescopes mounted on the nadir UARS
boom and the proton high-resolution spectral data converted to
number intensity units from the HEPS telescopes mounted on the zenith boom.
There are no HEPS proton measuring instruments on the nadir boom.
HEPS nadir boom electron data covers the rough range from 35 keV to
5 MeV. There are two telescopes mounted in different directions. These
measure -165 deg and +165 deg with respect to the spacecraft -z-axis and
along the spacecraft +x-axis. The HEPS electron units accumulate a spectrum
in 16.384 sec.
HEPS zenith boom proton data covers the rough range from 70 keV to
150 MeV for mounting angles less than 30 deg and 500 keV to 150 MeV for
mounting angles greater than 30 deg. There are six telescopes mounted
in four different directions. These measure -15 deg, +15 deg, +45 deg,
and +90 deg with respect to the spacecraft -z-axis and along the spacecraft
+x-axis. The HEPS proton units accumulate a spectrum in 16.384 sec.
The nadir HEPS electron unit in this file (labeled HEPS3) contains two
telescopes (labeled telescope 1 and telescope 2). Each telescope
contains a stack of solid state crystals. The signals from each
of the crystals are combined by energy processing electronics of the
instrument to yield two logical crystals or detectors, called the DE and
EE detectors. The DE detector has the rough energy range from 35 keV to
300 keV and the EE detector rough energy range is from 300 keV to 5 MeV.
These designations are used in the description of HEPS electron data.
There is one data file per day for the PEM HEPSB product, and the
temporal coverage is from Oct. 1, 1991 to Aug. 23, 2005. Spatial
coverage for the HEPSB product ranges between -57 and +57 deg latitude.
The HEPSB data files are written in network binary format. For more
information please review the PEM HEPSB data format guide.