Halo Events in Superhigh Energy Nuclear Interactions

Gamma family events with visible energies higher than 1015eV usually form halos in the emulsion chambers, which bring up some problems for further investigating the characteristics of superhigh energy nuclear interactions. At present, only a few gross quantities are used for describing the halo events. On the other hand, there are some fine structures inside the halo, which can give us more information. We have measured all the showers one by one in the superhigh energy family events and compared the results with those obtained by the method of halo measurements. Analyses and discussions are made for some special events.