SSNTD studies of lead nuclei fission induced by 0.5 and 1.0 GeV protons inside massive Hg, Pb and U targets

Full text: A series of experiments was carried out with 0.5 and 1.0 GeV protons accelerated at synchrophasotron LHE, Dubna, which hits the massive Hg, Pb and U targets. The beam profiles and volume intensities of both primary relativistic protons and secondary particles-mainly neutrons - were measured using polyterephtalate plastic track detectors inside the massive cylinder metallic block target mentioned above by counting of fission fragment tracks due to the induced fission of Pb nuclei. The beam diameter increases typically at the depth 10 cm of the target. With decreasing of the proton energy from 1.0 GeV to 0.5 GeV the number of fast projectiles drops down very significantly at the depth 20 cm. It means that the effective thickness of heavy metallic target of Hg, Pb or U for the electronuclear transmutation reactor assembly shall not exceed 20 cm for proton energy 0.5 GeV and 25-30 cm for 1.0 GeV protons of the further studies of beam profile and energy spectra of secondary particles inside massive heavy metal targets with different threshold target nucleus are planned