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The Particle Environment Monitor (PEM) level 2 High-Energy Particle Spectrometer (HEPS) A daily product contains electron high-resolution spectral data converted to number intensity units from the HEPS telescopes mounted on the zenith UARS boom. PEM was flown on the UARS spacecraft to measure the type, amount, energy, and distribution of charged particles injected into the Earth's thermosphere, mesosphere, and stratosphere. The PEM HEPS electron data covers roughly the energy range from 35 keV to 5 MeV. There are four telescopes mounted in different directions. These measure -15 deg, +15 deg, +45 deg, and +90 degrees with respect to the spacecraft -z-axis and along the spacecraft +x-axis. The HEPS electron units accumulate a spectrum in 4.086 seconds. There are two HEPS units in these data product files (labeled HEPS1 and HEPS2), each containing 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. There is one data file per day for the PEM HEPSA product, and the temporal coverage is from Oct. 1, 1991 to Aug. 23, 2005. Spatial coverage for the HEPSA product ranges between -57 and +57 degrees latitude. The HEPSA data files are written in network binary format. For more information please review the PEM HEPSA data format guide.

Map of Earth