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Solar Neutron Telescope Count Peaks Not Due to Gamma Rays

E. Bramlitt

in 35th International Cosmic Ray Conference

Contribution: pdf


Abstract: The 7 March 2011 count history of the solar neutron telescope (SNT) at Mt. Sierra Negra shows two peaks of equal intensity one hour apart. Several reasons have been given for a peak to be due to solar gamma rays, and it was the first experimental data of solar gamma rays reaching the ground. The significant result is solar gamma rays must have exposed aircraft flying at low latitudes. The Fermi satellite, in Earth orbit, detected a solar gamma ray event that day, but gamma rays did not arrive at Fermi until after the first SNT count peak, and the maximum flux at Fermi was less than the SNT peak count rate. Further, the second SNT peak occurred when the Sun was closer to the SNT at Mt. Mauna Kea, and that SNT did not register any count peaks. Weather data rule out thunderstorms as causing counts, and the SNT energy threshold excludes radioactivity. In conclusion, solar gamma rays were not counted at the ground, so there is no proof they reached flight levels.