Surprisingly intense neutron emission from a flare behind the limb of the sun

The Oriented Scintillation Spectrometer Experiment onboard the Compton Gamm a Ray Observatory observed a strong flux of neutrons from the behind-the-li mb flare that occurred on 1991 June 1. This is surprising if the neutrons w ere produced by thin-target interactions in the Sun's corona, as is suggest ed by gamma-ray observations of this hare made by Granat/PHEBUS. We compare neutron and gamma-ray observations of the June 1 hare with thick-target em issions observed from a hare 3 days later, where the interactions took plac e in the chromosphere and photosphere. A very hard spectrum for the acceler ated particles is required to account for the number of neutrons observed o n June 1 if they were produced by thin-target interactions in the corona.