by Boris Kuzhevsky, Cand. Sc. (Phys. & Math.), senior researcher, Institute of Nuclear Physics, Lomonosov Moscow State University A NEUTRON CORONA AROUND THE SUN? For several months our research team had been getting ready to obtain experimental proof on a neutron corona of the sun. Both the theoretical and the empirical data of astronomical observations showed continuous nuclear reactions to be occurring in the luminary's atmosphere.* So the sun should be surrounded by a corona of neutrons with mean energy of hundreds of thousands of electron-volts (eV). Yet detecting that corona in near space, from circumterrestrial orbit, seemed a Utopia. Neutrons are unstable particles. Each of them has a rather short lifetime, about 15 minutes, and so singly it can hardly make it to our planet. Their flux will be so small as to escape detection with conventional instruments-one needs super-sensitive gadgets with very great light-gathering power. But our Institute of Nuclear Physics has done this job: a team under Dr. Mikhail Panasyuk has developed such instruments on the basis of gas-discharge helium counters that have performed well in cosmic experiments. And thus equipped with this gear we-Oleg Nechayev, Viktor Shiltsyn of our staff, the author of this article and Igor Kuzhevsky, a schoolboy volunteer-set out for Tixi where we were to have a kit of instruments lifted in a balloon during a total solar eclipse. But why this day and this method? You see, we can register neutrons on the surface of the earth from outer space only if their energy amounts to hundreds of millions of eV and more. Otherwise these particles will never pierce the atmosphere of our planet. Colliding with the nuclei of oxygen and nitrogen atoms, they attenuate and develop * See: L. Miroshnichenko, "Solar Cosmic Rays: Puzzles and Discoveries", Science in Russia, No. 4, l995.-Ed. page 13 page 14 into thermal particles, whereupon they live on for yet another 0.1s to be absorbed by nitrogen ... Read more