Galactic Cosmic Ray "proton" count rates from CRIS
Hourly averaged CRIS E9 rate, after cuts to clean the data of artifacts and remove active periods (SEPs). The tabulated E9 rate is the AVERAGE of E9AB and E9CD. Omitted hours have avg E9 value of 0.0000.
The E9 rate is the singles rate of a detector used in anticoincidence to guard against penetrating particles (see CRIS instrument paper, Stone et al., SSRv 86, 285, 1998). As a singles rate, particles coming from any direction, even through the instrument and spacecraft walls, may be detected. The 3-mm thick Si detector has a threshold low enough (~300 keV) to trigger on minimum-ionizing protons. We have not carefully calibrated or modeled its response to particles, but we estimate that during solar quiet periods its count rate is dominated by GCR protons at energies >120 MeV. Because of its large area (4 10-cm diameter 3-mm thick Si detectors) the statistical accuracy of its count rate is quite high. This rate may be useful in studies of short-term GCR modulation (for example, it has been used for such a study in Ghanbari et al., ApJ 882:54, 2019).
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Plots of the data, the first page is an overview of the entire mission; subsequent pages are year-by-year..
PDF format. Last update: October 2024. -
Text file containing the rate data.
Text format. Last update: October 2024.
Contributed Data Page
Last modified: Oct 23, 2024