Search citation statements
Paper Sections
Citation Types
Year Published
Publication Types
Relationship
Authors
Journals
Ternary fission has been investigated by irradiating a natural uranium target with 13.5 MeV deuterons. The energy and angular distributions of ternary alpha particles do not differ from those observed in spontaneous or thermal neutron induced fission. The angle between alpha particles and light fragments has a most probable value of~r 82.1 ~ + 0.6 ~ with a dispersion (FWHM) of A~= 1B.4 ~ +-1,2 ~ The corresponding values of the energy distribution are Em = (14.8 * 0.5)MeV and ~E(FWHM) = (9.1 + 1.1)MeV.'The peak-to-valley ratio of the ternary fission fragment mass distribution is found to increase with increasing alpha energy. For near-symmetric mass division a strong broadening of the angular distribution is observed.Most of the light charged particles (icp) accompanying fission at low excitation energies are long range alpha particles (lra) with a sharply peaked angular distribution. The equatorial emission within a plane perpendicular to the fission axis is attributed to the origin of the alpha trajectories in the very vicinity of the neck, Many detailed investigations of spontaneous and thermal neutron induced ternary fission confirmed this hypothesis and showed the possibility of learning more about the scission point dynamics by studying various correlations of lra and fission fragment (ff) observables.In the present work, in-beam measurements were performed at the Rossendorf cyclotron U-120 by irradiating a natural UO 2 target with i].5 MeV deuterons. Both fission fragments were recorded with a large position-sensitive doubie-grid avalanche counter (DGAC) and a smaller paralielplate avaianche counter (PPAC) arranged perpendicular to the beam axis in 180 ~ geometry ( fig. i). The coincident light particles were identified by a time-of-fIight (TOF) system consisting of a small transmission PPAC and a large surface barrier detector as start and stop/E detectors, respectively. An additional veto PPAC for recording recoil nuclei was arranged under 45 ~ with respect to the beam axis in order to suppress random ff-~ coincidences caused by ~x-particies originating from (d,~)-reactions. Six parameter events consisting of TOFIco, Elco, zITff_ic o, ZITff-ff, Xand Y were recorUed in'list mode bnto magnetic disk.Every single event was off-line transformed into a physical relevant parameter set Mlco, Elco, A~ff_lcp, Mff, ~ff-lco and ~ . Making use-of the Viola systematics,-the ff mass was deduced from the ff TOF-difference corrected for flight path variations. The 4.104 accumulated events were then analyzed by generating different two-dimensional correlation fields. Besides the huge background of random coincidences, about i0 ) true lra events with E~ ii MeV could be identified.
Ternary fission has been investigated by irradiating a natural uranium target with 13.5 MeV deuterons. The energy and angular distributions of ternary alpha particles do not differ from those observed in spontaneous or thermal neutron induced fission. The angle between alpha particles and light fragments has a most probable value of~r 82.1 ~ + 0.6 ~ with a dispersion (FWHM) of A~= 1B.4 ~ +-1,2 ~ The corresponding values of the energy distribution are Em = (14.8 * 0.5)MeV and ~E(FWHM) = (9.1 + 1.1)MeV.'The peak-to-valley ratio of the ternary fission fragment mass distribution is found to increase with increasing alpha energy. For near-symmetric mass division a strong broadening of the angular distribution is observed.Most of the light charged particles (icp) accompanying fission at low excitation energies are long range alpha particles (lra) with a sharply peaked angular distribution. The equatorial emission within a plane perpendicular to the fission axis is attributed to the origin of the alpha trajectories in the very vicinity of the neck, Many detailed investigations of spontaneous and thermal neutron induced ternary fission confirmed this hypothesis and showed the possibility of learning more about the scission point dynamics by studying various correlations of lra and fission fragment (ff) observables.In the present work, in-beam measurements were performed at the Rossendorf cyclotron U-120 by irradiating a natural UO 2 target with i].5 MeV deuterons. Both fission fragments were recorded with a large position-sensitive doubie-grid avalanche counter (DGAC) and a smaller paralielplate avaianche counter (PPAC) arranged perpendicular to the beam axis in 180 ~ geometry ( fig. i). The coincident light particles were identified by a time-of-fIight (TOF) system consisting of a small transmission PPAC and a large surface barrier detector as start and stop/E detectors, respectively. An additional veto PPAC for recording recoil nuclei was arranged under 45 ~ with respect to the beam axis in order to suppress random ff-~ coincidences caused by ~x-particies originating from (d,~)-reactions. Six parameter events consisting of TOFIco, Elco, zITff_ic o, ZITff-ff, Xand Y were recorUed in'list mode bnto magnetic disk.Every single event was off-line transformed into a physical relevant parameter set Mlco, Elco, A~ff_lcp, Mff, ~ff-lco and ~ . Making use-of the Viola systematics,-the ff mass was deduced from the ff TOF-difference corrected for flight path variations. The 4.104 accumulated events were then analyzed by generating different two-dimensional correlation fields. Besides the huge background of random coincidences, about i0 ) true lra events with E~ ii MeV could be identified.
Nuclear fission accompanied by long-range alpha particles has been investigated. Fission was induced by irradiating a natural uranium target with 13.5 MeV deuterons. The alpha energy and angular distributions are similar to those observed in spontaneous or thermal neutron induced fission. The correlation angle between alpha particles and light fission fragments has a most probable value of O~s_~= 82.1 ~ ~ and a dispersion (FWHM) of A 0= 18.4~ 1.2 ~ The mean value and dispersion of the energy distribution are/~= 14.8 _+ 1.0 MeV and AE = 9.1 + 1.2 MeV (FWHM), respectively. The peak-to-valley ratio of the ternary fission fragment mass distribution is found to increase with increasing alpha energy. For near-symmetric mass division, a strong broadening of the angular distribution is observed. The results are discussed in the frame of a multichannelfission model.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.