Proton-induced production of residual radionuclides in lead at intermediate energies

Integral excitation functions for the production of residual nuclides are b asic quantities for the calculation of radioactive inventories of spallatio n targets in spallation neutron sources and in accelerator-driven devices f or energy amplification or for transmutation of nuclear waste. We present c omprehensive measurements of such data for the proton-induced production of residual nuclides from lead for proton energies between 64.8 MeV and 2.6 G eV. About 2000 individual cross-sections for 127 reactions were determined by means of off-line gamma -spectrometry. The phenomenology of excitation f unctions which exhibit clearly distinguishable reaction modes like multi-fr agmentation, three different types of asymmetric and symmetric fission and deep spallation is discussed. The experimental data are compared with calcu lations based on an intranuclear cascade/evaporation model in form of the L AHET code system. Together with earlier model exercises this comparison dem onstrates the necessity for further improvements of models and codes if med ium-energy activation cross-sections for applications shall be reliably pre dicted by theory. Today, experimental investigations remain indispensable. (C) 2001 Elsevier Science B.V. All rights reserved.