Authors & Affiliations
Gremyachkin D.E., Piksaikin V.M., Egorov A.S., Mitrofanov V.F., Samylin B.F., Mitrofanov K.V.
A.I. Leypunsky Institute for Physics and Power Engineering, Obninsk, Russia
Piksaikin V.M. – Leading researcher, Cand. Sci. (Phys.-Math.), A.I. Leypunsky Institute for Physics and Power Engineering.
Egorov A.S. – Researcher, A.I. Leypunsky Institute for Physics and Power Engineering.
Mitrofanov V.F. – Deputy Head of Department, A.I. Leypunsky Institute for Physics and Power Engineering.
Samylin B.F. – Senior Research Engineer, A.I. Leypunsky Institute for Physics and Power Engineering.
Mitrofanov K.V. – Head of Laboratory, A.I. Leypunsky Institute for Physics and Power Engineering.
In the present work, measurements of the relative abundances of delayed neutrons and half-lives of their precursors in the neutron induced fission of 238U in the energy range from 14 to 18 MeV, have been done. Measurements have been done using 4π-neutron detector consisted of 30 boron counters SNM-11 type embedded in polyethylene moderator. The data obtained experimentally have been processed taking into account the effect of detector blocking (of the detector) and effect of additional neutron source. Values of energy residual after neutrons emission have been calculated by the means of equation of the energy balance. Energy dependence of the average half-life of delayed neutron precursors emitted by the fission products on the final stage of the fission process of heavy nuclei and systematics of the average half-life of delayed neutron precursors allowed us to calculate average half-lives of delayed neutron precursors for the fission of compound nucleus arising in the process of emissive fission. Using the data obtained in the present work and data from different works the analysis of the chance structure of the emissive fission cross section of the 238U have been done in the terms of average half-life of delayed neutron precursors.
relative abundances, delayed neutrons, chance structure, emissive fission, average half-life
1. Roshchenko V.A., Piksaikin V.M., Korolev G.G., Egorov A.S. Time Features of Delayed Neutrons and Partial Emissive-Fission Cross Sections for the Neutron-Induced Fission of 232Th Nuclei in the Energy Range 3.2–17.9 MeV. Physics of Atomic Nuclei, 2010, vol. 73, no. 6, pp. 913–921.
2. Caldwell J.T., Dowdy E.J., Alvarez R.A., Berman B.L., Meyer P. Experimental Determination of Photofission Neutron Multiplicities for 235U, 236U, 238U, and 232Th Using Monoenergetic Photons. Nuclear Science and Engineering, 1980, vol. 73, no. 2, pp. 153-163.
3. Frehaut J. Progress in transactinium isotope neutron data measurements. Proc. III Advisory Group Meeting on Transactinium Isotope Nuclear Data. Upsala, 1984. IAEA-TECDOC-336, 1985. P. 105.
4. Piksaikin V.M., Kazakov L.E., Isaev S.G., Tarasko M.Z. et al. Energy Dependence of Relative Abundances and Periods of Delayed Neutrons from Neutron-Induced Fission of 235U, 238U, 239Pu in 6- and 8-Group Model Representation. Progress in Nuclear Energy, 2002, vol. 41, no. 1–4, pp. 203–222.
5. Kudyaev G.A., Ostapenko Yu.B. et al. Description and analysis of the chance structure in the cross section for neutron-induced fission of 233-238U. Yadernaya fizika, 1993, vol. 56, pp. 29–42.
6. Database. Abailable at: http://www.oecd-nea.org/janis/. (accessed 28.08.17).
7. Piksaikin V.M., Isaev S.G., Goverdovski A.A. Characteristics of Delayed Neutrons: Systematics and Correlation Properties. Progress in Nuclear Energy, 2002, vol. 41, no. 1–4, pp. 361–384.
8. Egorov A.S., Piksaikin V.M., Goverdovski A.A., Gremyachkin D.E., Mitrofanov K.V., Mitrofanov V.F., Samylin B.F., Vaishnene L.A., Moroz F.V., Vorobyev A.S., Shcherbakov O.A. Measurement of the delayed neutron characteristics in the interaction of relativistic protons with 238U nuclei. Progress in Nuclear Energy, 2017, vol. 97, pp. 106-114.
9. Sun K.H., Charpie R.A., Pecjak F.A., Jennings B., Nechaj J.F., Allen A.J. Delayed Neutrons from 238U and 232Th Fission. Physical Review, 1950, vol. 79, no. 1, pp. 3.
10. Hermann G., Fiedler J., Benedict G., Eckhardt W., Luthardt G., Patzelt P., Schussler H.D. Comparison of Observed Delayed-Neutron Abundances with Calculated Fission Yields of Neutron Precursors. Proc. Sympos. on Physics and Chemistry of Fission. IAEA, Vienna, 1965, vol. 2, pp. 197.
11. Hermann G. Recent Work on Delayed Fission Neutrons at the University of Mainz. Proc. of a Panel on Delayed Fission Neutrons. IAEA, Vienna, 1967, pp. 147.
12. Auguston R.H., East L.V., Menlove H.O. Delayed Neutron Abundances and Half-Lives for 14.9-MeV Fission. Program Status Report LA-4315-MS, Los Alamos National Laboratory, 1969, pp. 18.
13. Benedict G., Luthardt G., Hermann G. Delayed-Neutron Yields from Fission of 238U and 232Th by 14.8-MeV Neutrons. Radiochimica Acta, 1972, vol. 17, no. 1, pp. 61.
14. Brown M.G., Lyle S.J., Marti E.B.M. Delayed Neutron Yields from 14.8 MeV Neutron Induced Fission of 238U, 232Th, and 231Pa. Radiochimica Acta, 1971, vol. 15, no. 3, pp. 109.
15. East L.V., Auguston R.H., Menlove H.O. Delayed Neutron Abundances and Half-Lives for 14.7-MeV Fission. Program Status Report LA-4605-MS, Los Alamos National Laboratory, 1970, pp. 15.
16. Bucko M. Investigation of Delayed Neutrons Arising from the Fission of 238U Nuclei by 14.7-MeV Neutrons. Soviet Atomic Energy, 1966, vol. 20, pp. 187.
17. Maksyutenko B.P. et al. Delayed Neutrons from Nuclear Fission by Neutrons with Energies of 15 to 21 MeV. Proc. of a Panel on Delayed Fission Neutrons. IAEA, Vienna, 1967, pp. 203.
18. Notea A. Delayed Neutrons from Thermal and 14 MeV Neutron Fission of Uranium and Thorium. Research Laboratories Annual Report. January through December 1968, IA-1190, Israel AEC, 95 (1969).
19. Piksaikin V.M., Egorov A.S., Mitrofanov K.V. The absolute total delayed neutron yields, relative abundances and half-lives of delayed neutron groups from neutron induced fission of 232Th, 233U, 236U, 239Pu and 241Am. INDC(NDS)-0646, 2013.
20. Kravtsov V.A. Massy atomov i energii svyazi yader [Masses of atoms and binding energies of nuclei]. Moscow, Atomizdat Publ., 1974.
21. Svirin M.I., Lovchikova G.N., Trufanov A.M. Osobennosti formy spektrov, soprovozhdayushchikh emissionnoe delenie 238U neytronami [Features of the shape of the spectra accompanying the emission fission of 238U neutrons]. Yadernaya fizika, 1997, vol. 60, no. 5, pp. 812–832.
22. Boykov G.S., Dmitriev V.D., Kudyaev G.A., Ostapenko Yu.B., Svirin M.I., Smirenkin G.N. Spektr neytronov pri delenii 232Th, 235U, 238U neytronami s energiey 2,9 i 14,7 MeV (nizhe i vyshe poroga emissionnogo deleniya) [The neutron spectrum in the fission of 232Th, 235U, 238U neutrons with energies of 2.9 and 14.7 MeV (below and above the emission fission threshold)]. Yadernaya fizika, 1991, vol. 53, no. 3.
23. Ignatyuk A.V., Maslov V.M. Opisanie secheniy deleniya transuranovykh yader bystrymi neytronami [Description of fission cross sections of transuranium nuclei by fast neutrons]. Yadernaya fizika, 1990, vol. 51, no. 5, pp. 1227–1237.