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Ulysses COSPIN High Energy Telescope Daily Average Proton and Helium Fluxes


Availability: At NSSDC, Ready for Electronic Access

Time span: 1990-10-23 to 2004-09-08


This data collection consists of daily average fluxes in certain energy intervals for interplanetary protons and helium nuclei stopping in the detectors K1 - K6 of the High Energy Telescope (HET) sensor in the COSPIN experiment on Ulysses. The particles contributing to these fluxes have been identified by pulse height analysis which allows subtraction of telescope backgrounds and computation of fluxes with known geometric factors. The data file in ascii table format includes proton fluxes in /cm2-s-sr-MeV units at 39 - 70 MeV and 71 - 94 MeV, and helium fluxes in /cm2-s-sr-MeV/n units at 39 - 71 and 72 - 95 MeV/nucleon. Errors are also given for each flux in the same units and correspond to one-sigma counting errors for Poisson statistics. Other errors due to uncertainties in geometric factors and energy bands are estimated at 10 to 20 percent of the measured flux. During solar energetic particle events, HET count rates are dominated by low energy protons, and fluxes of higher energy protons and helium nuclei may be underestimated. Missing, invalid, or meaningless data are represented by values of -1.0. Times are given at the mid-point of each daily interval in fractional year and day of year (noon Jan. 1 = 1.5). The HET sensor is described in detail by Simpson et al. (Astron. & Astrophys., vol 92, pp. 365-399, 1992).

This collection is available on-line under directory het_pha_flux_h_he_1day/ at:

Alternate Names

  • COSPIN HET 24-hr Proton,Hel Flux
  • SPDF0793


  • Space Physics: Heliospheric Studies


  • 90-090B-02G

Additional Information



Questions and comments about this data collection can be directed to: Dr. John F. Cooper



NameRoleOriginal AffiliationE-mail
Dr. R. Bruce McKibbenGeneral

Selected References

  • Simpson, J. A., et al., The Ulysses cosmic ray and solar particle investigation, Astron. Astrophys. Suppl. Ser., 92, No. 2, 365-399, Jan. 1992.
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