_v02 Data files provide more accurate He++ fluxes. BUT there is a software error in the file generation software that leads to UNDER REPORTING the fluxes in regions of high count rate. High count rates are found in the radiation belts (primarily background) and in the cusp. Data from _V02 files should not be used for quantitative investigations of cusp fluxes.

_v03 Data files have been regenerated with corrected software. They have the same format as _v02 data files.

Limitations of _v01 data files

• He⁺⁺ fluxes, where reported, are not overstated.

• The algorithm generating the files has been significantly improved to more accurately subtract backgrounds arising from "spill over" from H⁺ into the He⁺⁺ and other ion's channels.

• Estimates of the uncertainties of the fluxes in _v02 files include estimates of the uncertainty introduced by the new algorithm. I.e. 50% of the applied corrections are added to the values of the Sigma_H, Sigma_O, Sigma_He_1, and Sigma_He_2 variables to account for the uncertainty introduced by making the corrections for "spill over". Note that the part of the uncertainty introduced by the correction for "spill over" is a systematic uncertainty which cannot be reduced by averaging.

• In order to identify data with excessive spill over, only those values of Flux variables (Flux_H, Flux_O, Flux_He_1, and Flux_He_2) are reported as valid data if their associated uncertainties are not too large, or if spill over is expected to be minimal which is the case if the countrate is low or if the countrate is dominated by background. The specific algorithm is to report valid data:
  IF
  • The data value is greater than its estimated uncertainty

    OR

  • The "Fast Event Counter" value corresponding to the total counts obtained at the specific energy step and pitch-angle is less than 400. The Fec value included in the high resolution data file is a sum of the fast event counter value in all of the energy steps sampled in one data interval.

    OR

  • The "Background Counting Rate" value corresponding to the total background counts is greater than the number in the "Fast Event Counter." The Bcr value included in the high resolution data file is a sum of the background sampled by the whole detector in one data interval.

  Otherwise the data value is set to the CDF standard fill value (-1.0 x 10³¹ ) to indicate that the data value is not valid. Note this test is applied for each element in the Flux_H, Flux_O, Flux_He_1, and Flux_He_2 variables.

• To retain compatibilty with the TIMAS PAPCO display module the meaning of the "Quality" variable has been changed.

  The TIMAS Papco module defines two levels of data quality:

  • High quality: When the quality flag is less than or equal to 2.
  • Adequate quality: When the quality flag is less than or equal to 4.
  • _v01 values of the Quality flag
    • 0 OK
    • 1 Some data missing.
    • 2 Slight MCP saturation.
    • 3 Moderate MCP saturation.
    • 4 Severe MCP saturation.
    • 5 Warning flags set.
    • 99 No valid data.
  • _v02 values of the Quality flag
    • 0 OK
    • 1 Some data missing.
    • 2 More than 5% of data missing (i.e. set to the CDF standard fill value)
    • 3 Not used.
    • 4 Not used
    • 5 Warning flags set.
    • 99 No valid data.

• H⁺/He⁺⁺ ratios calculated from _v02 values must be interpreted with caution. They are valid only to the extent that the the calculation accurately reflects the uncertainty values reported in the Sigma_H and Sigma_He_2 variables and any missing (i.e. having excessive spill over) Flux_H and Flux_He_2 data values at, typically, energies where the maximum fluxes are encountered in the cusp.

NASA Common Data Format Skeleton (i.e., descriptor) file for _v02 data files

_v03 Data files have been regenerated with corrected software. They have the same format as _v02 data files.
NASA Common Data Format Skeleton (i.e., descriptor) file for _v03 data files