SAMPEX HILT 6-Second Rate Data Documentation

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This data set consists of 6-second particle rates from the HILT instrument. The data set covers the complete mission, from launch through 2004-182. The rates are not calibrated or converted into physical units. Calibrated particle intensities are also available.

The data are derived from the SAMPEX RS Set data, documented in the SAMPEX NGDF Data File Description.

The time-stamps for the attitude/orbit (PS Set) data have been synced (in ground data processing) with the time-stamps for these 6-second rate data, and with the time-stamps for the particle intensity data.

Thus, the timestamps in each of these data sets may be used to associate the appropriate attitude/orbit data with each 6-second intensity or rates data record.

In addition, the intensity, attitude/orbit, and rates data have been filled so that they all contain the same number of records per day.

The Basic Rates are counts accumulated over 6-second intervals, while the multiplexed rates have a time resolution of 24 or 48 seconds (see individiual descriptions below).
Note: The Basic rates HE1, HE2, HZ1, and HZ2 are raw accumulator counts, and are not corrected for effects such as background, livetime, and gain changes.

More information on the SAMPEX spacecraft, instruments, operations, and the science data may be found in the SAMPEX Mission and Instrument Documentation.

Description of each data field

  1. year:
    Four-digit year

  2. day:
    Day of year (starting at 1)

  3. hr:
    Hour of day

  4. min:
    Minute of hour

  5. sec:
    Second of minute

  6. fp_year:
    Year, floating-point

  7. fp_doy:
    Day of year, floating-point

  8. sec_of_day:
    Second of day

  9. Subcom:
    The subcom defines the multiplexed rates for HILT, MAST, and PET. Valid values are 6 thru 21. Thus, each subcom cycle lasts 16×9 = 96 seconds.

    Basic Rates

    Note: The Basic rates HE1, HE2, HZ1, and HZ2 are raw accumulator counts, and are not corrected for effects such as background, livetime, and gain changes.

  10. HE1:
    Helium, 4.3-9 MeV/Nucleon. 6 second time resolution.

  11. HE2:
    Helium, 9-38 MeV/Nucleon. 6 second time resolution.

  12. HZ1:
    Z>=6, 8.2-42 MeV/nucleon (for 16O). 6 second time resolution.

  13. HZ2:
    Z>=6, 42-220 MeV/nucleon (for 16O). 6 second time resolution.

    Multiplexed Rates

    The multiplexed rates include singles rates of the individual detectors and of the coincidence logic. The energy ranges of these rates are provided in Table II of the HILT instrument paper.

  14. SSD1:
    SSD Row 1 singles rate. 24 second time resolution. Read out when Subcom=6, 10, 14, 18

  15. SSD2:
    SSD Row 2 singles rate. 24 second time resolution. Read out when Subcom=7, 11, 15, 19

  16. SSD3:
    SSD Row 3 singles rate. 24 second time resolution. Read out when Subcom=8, 12, 16, 20

  17. SSD4:
    SSD Row 4 singles rate. 24 second time resolution. Read out when Subcom=9, 13, 17, 21

  18. Strobe:
    Logic rate, Singles rate. 48 second time resolution. Read out when Subcom=6, 14

  19. PCF0:
    Front proportional counter singles rate. 48 second time resolution. Read out when Subcom=7, 15

  20. IK0_AC:
    Ionization chamber singles rate. 48 second time resolution. Read out when Subcom=8, 16

  21. CSI:
    CsI crystal singles rate. 48 second time resolution. Read out when Subcom=9, 17

  22. PCR0:
    Rear Proportional counter Singles rate. 48 second time resolution. Read out when Subcom=10, 18

  23. NO_PC_SSD:
    Logic rate, singles rate. 48 second time resolution. Read out when Subcom=11, 19

  24. Pile_up:
    Logic rate, Singles rate. 48 second time resolution. Read out when Subcom=12, 20

  25. Inval_Ary:
    Logic rate, Singles rate. 48 second time resolution. Read out when Subcom=13, 21

    System Idle Rates

    Idle_1 and Idle_2 are used for dead-time correction of the 4 Basic Rates HE1, HE2, HZ1, HZ2. The dead-time correction algorithm for 6s accumulation time is:
    HE1_cor = HE1 * beta1
    HE2_cor = HE2 * beta2
    HZ1_cor = HZ1 * beta1
    HZ2_cor = HZ2 * beta1
    beta1 = 1.0 / ((Idle_1+Idle_2)/6.0E6-1.0)
    beta2 = 1.0 / (Idle_1 / 6.0E6)

  26. Idle_1:
    IDLE time, 6 second time resolution, in microsec.

  27. Idle_2:
    IDLE time, 6 second time resolution, in microsec.

    Attitude/Orbit

    A subset of the SAMPEX attitude/orbit data. For more, see the Complete attitude/orbit data set.

  28. GEO_Long
    Longitude in GEO coordinate system (0 to 360 degrees).

  29. GEO_Lat
    Longitude in GEO coordinate system (0 to 360 degrees).

  30. L_Shell
    L-shell parameter.

  31. Invariant_Lat
    Invariant latitude (degrees).

  32. Pitch
    Pitch angle of a particle heading down the instrument boresight (i.e., angle between S/C z-axis and (-1) times the local magnetic field vector), in degrees.

  33. Magnetic_Lat
    Algebraic magnetic latitude (degrees).

  34. Mag_Local_Tm
    Local time at magnetic equator along current field line (hr) ECD.

  35. Att_Flag
    Flag, data quality flag indicating source of attitude information (Applies only to pitch angle for the attitude/orbit data subset included here).
    Executive summary: flag =0,1,100, or 101 means attitude is OK. Other values indicate attitude is not OK.