PEPE CODMAC level 2 data format (F.Crary, 13 JAN 02) There will be one file per product, per day. The file shall contain measurements which begin between 00:00:00 on that day and 00:00:00 on the following day (SCET). Measurement numbers will be the same for all data products, i.e. if a measurement of ELC data is missing, the measurement numbers in the ELC file will skip the appropriate number. The files will be flat, binary data, with a fixed series of values repeated as many times as necessary. This format only describes the data products generated during and around the encounter with P/19 Borrelly. File names are of the form xxxyyddd.dat where: xxx = elc Electron data hsk Housekeeping data ion Ion singles data log Ion logicals data mq Ion mass over charge data tof Ion time of flight data yy = 01 Year ddd = Day of year Electron data are the flux of electrons as a function of energy and angle. Housekeeping data are selected housekeeping values of use in analysis of the PEPE data. Ion singles are the flux of all ions as a function of energy and angle. (In terms of instrument operations, these are the number of start counts in the time of flight system, regardless of the ion's time of flight, or even whether or not a valid stop signal was measured.) Ion mass over charge data are the flux of selected ions as a function of energy and angle. The ions are selected on the basis of time of flight (i.e. composition) For example, the MQ 0 data are the energy/angle spectra of all proton. The 15 MQ bins have a one-to-one correspondence to time of flight, but not necessarily to species (e.g. most of the counts in MQ bin 1 are He++, but some protons also fall into the MQ 1 time of flight bin.) TOF spectra are the flux of ions as a function of time of flight (related to composition) and summed over all energies and angles. All integers are unsigned =========================================================================== Electron (elc*) data format: Name Type Length Description =========================================================================== Measurement number Integer 16 Measurement number from start of day Time Integer 32 Measurement start time, sec. from J2000 Offset time Integer 16 Seconds from start of measurement Energy Step Integer 16 Energy step number Elevation Step Integer 16 Elevation step number Data, Azimuth 1 Integer 16 Counts in azimuth 1 Data, Azimuth 2 Integer 16 Counts in azimuth 2 Data, Azimuth 3 Integer 16 Counts in azimuth 3 Data, Azimuth 4 Integer 16 Counts in azimuth 4 There are 144 bits per row and 256 rows per measurement =========================================================================== Ion singles (ion*) data format: Name Type Length Description =========================================================================== Measurement number Integer 16 Measurement number from start of day Time Integer 32 Measurement start time, sec. from J2000 Offset time Integer 16 Seconds from start of measurement Energy Step Integer 16 Energy step number Elevation Step Integer 16 Elevation step number Data, Azimuth 1 Integer 16 Counts in azimuth 1 Data, Azimuth 2 Integer 16 Counts in azimuth 2 Data, Azimuth 3 Integer 16 Counts in azimuth 3 Data, Azimuth 4 Integer 16 Counts in azimuth 4 Data, Azimuth 5 Integer 16 Counts in azimuth 5 Data, Azimuth 6 Integer 16 Counts in azimuth 6 Data, Azimuth 7 Integer 16 Counts in azimuth 7 Data, Azimuth 8 Integer 16 Counts in azimuth 8 There are 208 bits per row and 512 rows per measurement =========================================================================== Logicals (LOG) data format: Name Type Length Description =========================================================================== Measurement number Integer 16 Measurement number from start of day Time Integer 32 Measurement start time, sec. from J2000 Offset time Integer 16 Seconds from start of measurement Energy Step Integer 16 Energy step number Elevation Step Integer 16 Elevation step number Data, Coarse starts Integer 16 Start counts in coarse azimuths Data, Fine starts Integer 16 Start counts in fine azimuths Data, Stops Integer 16 Stop counts Data, Resets Integer 16 Resets There are 144 bits per row and 128 rows per measurement =========================================================================== Mass over charge (MQ) data format: Name Type Length Description =========================================================================== Measurement number Integer 16 Measurement number from start of day Time Integer 32 Measurement start time, sec. from J2000 Offset time Integer 16 Seconds from start of measurement Energy Step Integer 16 Energy step number Energy step Data, bin 0 Integer 16 Counts in M/Q bin 0 Energy step Data, bin 1 Integer 16 Counts in M/Q bin 1 Energy step Data, bin 2 Integer 16 Counts in M/Q bin 2 Energy step Data, bin 3 Integer 16 Counts in M/Q bin 3 Energy step Data, bin 4 Integer 16 Counts in M/Q bin 4 Energy step Data, bin 5 Integer 16 Counts in M/Q bin 5 Energy step Data, bin 6 Integer 16 Counts in M/Q bin 6 Energy step Data, bin 7 Integer 16 Counts in M/Q bin 7 Energy step Data, bin 8 Integer 16 Counts in M/Q bin 8 Energy step Data, bin 9 Integer 16 Counts in M/Q bin 9 Energy step Data, bin10 Integer 16 Counts in M/Q bin 10 Energy step Data, bin11 Integer 16 Counts in M/Q bin 11 Energy step Data, bin12 Integer 16 Counts in M/Q bin 12 Energy step Data, bin13 Integer 16 Counts in M/Q bin 13 Energy step Data, bin14 Integer 16 Counts in M/Q bin 14 There are 312 bits per row and 64 rows per measurement =========================================================================== Time of flight (TOF) data format: Name Type Length Description =========================================================================== Measurement number Integer 16 Measurement number from start of day Time Integer 32 Measurement start time, sec. from J2000 Data, bin 0 Integer 16 Counts in TOF bin 0 Data, bin 1 Integer 16 Counts in TOF bin 1 ... Data, bin 1023 Integer 16 Counts in TOF bin 1023 There are 16432 bits per row and one row per measurement =========================================================================== Housekeeping (HSK) data format: (Data files TBS) Name Type Length Description =========================================================================== Measurement number Integer 16 Measurement number from start of day Time Integer 32 Measurement start time, sec. from J2000 Time Integer 32 Measurement start time, SCLK Integration time Integer 16 Integration time per sample, multiples of 28.62 ms (legal values are 1, 10 and 20) SC_IPS Integer 16 Ion propulsion system thrust level, [1/10 mN] SC_RSC_SUM Integer 16 RSC thruster on time, [1/16 sec] SC_SUN_AZ Integer 16 Sun azimuth, s/c coordinates [deg] SC_SUN_EL Integer 16 Sun elevation, s/c coordinates [deg] ION_HIST_MOD Integer 8 TBS ION_HIST_PK Integer 8 TBS ION_HIST_DMD Integer 8 TBS ION_HIST_DPK Integer 8 TBS 192 bits/measurement, 1507 measurements in the encounter data set