Fission of Pb nuclei induced by 0.5, 1.0, 1.5, 3.7 and 7.4 GeV protons in the volume of massive U/Pb and Pb targets

Experiments with relativistic protons accelerated at the Synchrophasotron L HE, Dubna, with energies of 0.5, 1.0, 1.5, 3.7 and 7.5 GeV hitting massive targets of (nat. U)/Pb and Pb were carried out using SSNTD during the years 1996-1999. The beam profiles and intensities of both primary particles and fast secondary neutrons were measured inside the massive cylinder blocks o f Pb and U by counting fission fragment tracks due to the induced fission o f Pb nuclei. The beam diameter typically increases by 20-30% at the depth 1 0 and 20 cm. With increasing the energy of protons the number of secondary neutrons increases with the depth of the target. Further studies on beam profile measurements inside the massive heavy metal targets are discussed. (C) 2001 Elsevier Science Ltd. All rights reserved.