Proton Induced Fission Cross Sections
Proton Induced Fission Cross Sections for Heavy Nuclei in the Energy Range 200-1000 MeV
Tech Area / Field
- PHY-PFA/Particles, Fields and Accelerator Physics/Physics
- FUS-HSF/Hybrid Systems and Fuel Cycle/Fusion
8 Project completed
Senior Project Manager
Bugaev D V
Nuclear Physics Institute, Russia, Leningrad reg., Gatchina
- FEI (IPPE), Russia, Kaluga reg., Obninsk
- JAERI / Tokai Research Establishment, Japan, Tokai Mura\nJAERI / Tokai Research Establishment, Japan, Tokai Mura
Project summaryThe main purpose of this project is the measurements of fission cross sections of natPb, 209Bi, 232Th, 233, 235, 238U, 237Np and 239Pu target nuclei induced by protons with energies from 200 to 1000 MeV with an interval of 100 MeV and with an accuracy of 5-10%.
The need for data on the total cross sections of heavy nuclei is motivated by new energy production concepts with the help of accelerator driven systems (ADS), nuclear waste transmutation technologies, accelerator and cosmic device radiation shields, as well as by applications in medicine and solid state investigations. All existing experimental data on total cross sections of the fission process induced in heavy nuclei by protons are dispersed (sometimes up to 100%) due to different experimental methods and various selection criteria. Moreover, for some nuclei total fission cross sections are absent in the chosen energy range.
Experiments are planned to be carried out at the external proton beam of the 1 GeV PNPI synchrocyclotron. Proton beams in the energy range 200 - 900 MeV will be obtained by decreasing the energy of the primary 1 GeV proton beam with a suitable absorber as well as by secondary beam production beam production in thick copper targets. The transportation and formation system of the external proton beam, consisting of a bending magnet and quadrupole magnetic lenses, represents a magnetic spectrometer with an energy resolution of 30 MeV in the energy range 200 - 1000 MeV.
Fission fragments produced in the target by the proton beam will be detected in coincidence using improved experimental equipment for fission cross section measurements on the basis of gas parallel plate avalanche counters with large solid angle acceptance.
For the planned experiments, the experimental installation which was successfully used for measurements of fission cross sections of some nuclei at 1 GeV proton beam will be improved so that the range of nuclei to be investigated can be enlarged. The experimental part of this work includes the design and construction of a new kind of parallel plate avalanche detector, target preparation, improvement of the proton beam installation so that the beam energy can be decreased and construction of new electronic modules. As a result measurements of the total fission cross sections with an accuracy of better than 10% are expected.
For the first year, the proton beam installation will be updated in order to provide proton beams with energies from 1000 down to 200 MeV, the experimental arrangement for measurements of fission cross sections will be improved, the targets will be prepared, and test runs will be performed.
For the second and third years, we plan to measure fission cross sections of natPb, 209Bi, 232Th, 233, 235, 238U, 237Np and 239Pu nuclei induced by protons from 200 to 1000 MeV with an interval of 100 MeV, to carry out experimental data processing, and to compare the obtained results with theoretical calculations.
In addition to these planned measurements the project will also involve simulations of the proton-nucleus interactions with intranuclear cascade calculations that take into account the direct and preequilibrium processes, the de-excitation of recoils, and the statistical model. They will be performed using computer codes developed at PNPI and elsewhere.
As a result new experimental absolute total fission cross sections of natPb, 209Bi, 232Th, 233, 235, 238U, 237Np and 239Pu nuclei induced by protons with energies from 200 to 1000 MeV will be obtained with an accuracy of better than 10%. Comparisons with theoretical calculations will also be carried out.
In addition to the Russian participants, scientists experienced in fission cross section measurements from Florida State University and George Washington University, USA, will take part in this project. They will participate in data analysis, theoretical calculations, comparison of the experimental and calculated results as well as in seminars and workshops during the course of the project.