Topology of 16O fragmentation at 4.5 A Gev/c with emulsion nuclei is reported. The charges Z2 of projectile fragments were carefully measured and identified.The experimental measurements of partial production cross-section of the multiple helium fragments emitted from 16O beam are studied and compared with that obtained from different projectiles and various energies. We present results using a special type of events,selected to separate the events due to collision of singly charged particle Z=1 from 16O compared with collision of neutron from 16O beam. Those when neutron from 16O is collided. We describe a topological structure of such events.