Nuclear charge dispersion of products in the light-mass region formed in the fission of 233U by protons of energy 20–85 MeV

Abstract

The independent formation cross sections of 9~b and 9~b and the cumulative yields of 95zr, 97Zr and 99.Mo from the fission of 233ij by protons were deter.mined radiochemically for bambarding energies of 20, 30, 40, 50, 60, 72 and 85 MeV, and charge dispersion curves were constructed from these cross sections. The displacement of the most probable charge from stability was found to be between 2.9 and 3.2 charge units, and the full-width at half-ma.x:imum of the curves was about 2.9 charge units. These results are very close to those for the charge dispersion of the light-mass products of the fission of 2.3.!U and 23Bu in this energy range, and thus differ from those for the charge dispersion of the heavy mass products, which show a marked dependence on the neutron-to-proton ratio of the target.It is proposed that the extra neutrons in the heavier members of a set of isotopic fission targets appear in the heavy-mass fission fragments. List of FiguresMass distributions for the fission of 23àU induced by protons of 10 -150 MeV. 5The effect of isotopie charge dispersion of a variation of with masseThe effect on isotopie charge dispersion of a variation of N/Z p with masse 10(ZA-Z ) as a function of bombarding energy, for varioRs targets. ~2The energies at which the excitation functibns of heavy-mass fragments reach their maxima~' and the FWHM of the charge dispersions, for various targets. 12The target holder.A peak in a Y -ray spectrum as recorded by a Ge(Li) detector and 1600-channel analyser.The annihilation radiation peak of M·Cu.The excitation function of 9SNb (independent yield).The excitation function of 97Nb (independent yield).The excitation function of 9SZr (cumulative yield).The excitation function of 97Z r (cumulative yield).The excitation function of 99Mo (cumulative yield). Charge dispersion curve at 85 MeV ( <r Y.ê. N/Z).Charge dispersion parameters for the fission of 233U, 23SU, and 23EU as a function of bombarding energy.Mass distributions from the thermal-neutron fission of 239Pu and 2~lPu.Mass distributions from the thermal-neutron fission of 233U and 23SU. iii Table l Table II List of Tables Energies and abundances of -rays observed.Cross sections for the monitor reaction 65Cu(p,pn)6~Cu. 20.24 Table III Formation cross sections. 29 Table IV Parametèrs of charge dispersion curves for 233 U • 43 Table V Parameters for charge dispersion curves for 233U, 235U, and 238U.45 Table VI Neutron emission characteristics of the compound nucleus and the heavy fragment for the proton-induced fission of 233U, 235U, and ~38U.47 Table VII Comparison of 233U and 235U fission. 50 Heavy nuclei may be excited and induced to fission by bombardment with neutrons, protons, or heavier particles. At low bombardment energies the projectile is absorbed into the nucleus, and the added energy distributed through the whole compound nucleus. At energies in the order of 50 MeV the mechanism becomes that of direct interaction between the projectile and a few of the nucleons within the nucleus. The incomin...

Nuclear charge distribution in the region of symmetric fission of 238U by protons of energy 20–85 MeV

“…Nevertheless, a variety of fissile systems (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14) has been studied at medium energies.…”