GENERATION OF NEUTRONS AND RADIOACTIVE NUCLIDES BY HADRONIC CASCADES IN WATER

The yields of neutrons and the spatial distributions of radionuclides generated by neutrons in hadronic cascades are computed. Simulation th at employs the SHIELD code is based on the Dubna version of the cascad e model for describing hadron-nucleus interactions and on the quark-gl uon string model for describing interactions of high-energy particles. Cascade arising from interactions between negative pions with energie s in the range 0.3-10.0 GeV and nuclei in water are considered. A code simulating nuclear deexcitation is used to take into account Fermi br eakup, multifragmentation, and evaporation (or fission). Neutron trans port is included in the analysis through the original algorithm LOENT. More than 50% of neutrons and radionuclides generated by them are dis tributed at distances greater than 0.57 m form the shower core. The re sults may be used to estimated background due to cosmic muons in exper imental searches for rare and hypothetical processes.