30TH INTERNATIONAL COSMIC RAY CONFERENCE Upper limits on high-energy solar neutrons from satellite-detected flares with the Yangbajing neutron monitor

We report a systematic search for solar neutrons using the Ya ngbajing neutron monitor. Making use of the onset times of >∼ 25 keV hard x-ray emissions detected by BATSE, we search the Yangbajing neutron monitor data for possible count enhance ments due to solar neutrons from the BATSEdetected flares. As a result, statistically significant sign als from individual flares were not found. We hence deduced 99 % confidence level upper limits on > 50 MeV solar-neutron flux at 1 AU, comparing them with absolute neutron fluxes deduced from past positive det ctions.