BRIEF DESCRIPTION Energetic Electron and Proton Detector (Principal Investigator: Keppler) HELIOS-A and -B spacecrafts were the pair of deep space probes developed by the Federal Republic of Germany (FRG) in a cooperative program with NASA. The purpose of the mission was to make pioneering measurements of the interplanetary medium from the vicinity of the earth's orbit to 0.3 AU. The objective of the experiment (E8) was to study the origin and the distribution mechanism of low-energy electrons and protons. The instrument, a magnetic spectrometer, consisted of six semiconductor detectors with the field of view in the plane of the ecliptic. Species separation was achieved by an inhomogeneous magnetic field oriented perpendicular to the particle path. Four electron and two proton detectors measured electrons from 20 to 1000 keV and protons from 80 to 1000 keV. The proton measurements were made with a two-detector telescope employing coincidence and anticoincidence logic. Both particle species were measured in 16 energy channels through pulse-height analysis. For further information see pp. 261-263 of Raumfahrtforschung, v.19, n. 5, 1975. The h-a-ep*.dat and h-b-ep*.dat files contains hourly averaged electron and proton data written in ASCII-codes. Each named file contains data blocks of fixed length (4440 bytes) and one blank line. Each item within one data block has a length of 4 bytes. Each contains a count of the number of hourly intervals in the record. Electron as well as proton averages pertain to 16 sectors in the ecliptic plane, with sector 1 pointing to the sun. For each sector, the electron data pertain to 15 energy channels, spanning the total range of 17-835 keV, plus a channel that counts electrons of energy greater than 835 keV. Likewise, for protons, 15 channels cover the total range of 21-677 keV; the 16-th channel counts protons of E>677 keV. For h-a-ep*.dat files: Time Coverage: 1974/12/10 - 1980/12/31 For h-b-ep*.dat files: Time Coverage: 1976/01/15 - 1980/03/08 The 1110 items are described in the following table: Item Type Description ____________________________________________________________________________ 1 Integer ((YEAR - 1974) * 366 + DOY) * 24 + HOUR 2 Integer YEAR (begin of time interval) 3 Integer DOY (begin of time interval) 4 Integer HOUR (begin of time interval) 5 Integer MINUTE (begin of time interval) 6 Integer Length of time interval in minutes (60) 7 Real Importante for tape generation, only 8 Real sequence number of the source tape 9 Real reel number of the source tape 10 Real 0 - Helios A, 1 - Helios B 11 Real 1 - E8 mode A, 0 - E8 mode B 12-14 Real not defined 15 Real rate, F - data channel 1, sector 1, electrons 16 Real corresponding measuring time <= 3600/256 sec 17-46 Real is repetitions of 15-16 for energy channels 2-16, sector 1 47-526 Real is repetitions 0f 15-526 for the sectors 2-16 527-1038 Real same as 15-526 for protons 1039-1040 Real rate, measuring time <= 3600/32 sec for R-electrons, sector 1 1041-1070 Real is repetitions of 1039-1040 for the sectors 2-16 1071-1102 Real same as 1041-1070 for protons 1103-1104 Real W4 (rate, measuring time <= 3600sec) 1105-1106 Real W23 (rate, measuring time <= 3600sec) 1107-1108 Real W24 (rate, measuring time <= 3600sec) 1109-1110 Real W44 (rate, measuring time <= 3600sec) blank line ____________________________________________________________________________ Note: Negative rates indicate missing or invalid data.