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The capabilities of lead slowing-down neutron spectrometry are demonstrated. The paper reviews the results of a series of studies on the measurement of the fission cross sections of curium isotopes 243Cm, 244Cm, 245Cm, 246Cm, 247Cm, and 248Cm by neutrons with energies below 100 keV. These studies were carried out by a joint group of researchers from the Institute for Nuclear Research, Russian Academy of Sciences (INR RAS), and the State Scientific Center of the Russian Federation, Leypunsky Institute of Physics and Power Engineering (SSC RF LIPPE) using an SVZ-100 lead slowing-down neutron spectrometer. This third-generation spectrometer possesses high luminosity, enabling the investigation of neutron-nuclear processes in microgram-scale samples of radioactive nuclides, which is unattainable in experiments using time-of-flight spectrometry. The results of research at the INR RAS and the SSC RF LIPPE are reflected in international nuclear data repositories, supplementing known experimental data and indicating, in several cases, the need for adjustments to recommended values. [ABSTRACT FROM AUTHOR]

This paper is an overview of the results obtained by a collaborative team of researchers from the Institute for Nuclear Research, Russian Academy of Sciences (INR RAS), and State Scientific Center of the Russian Federation—Institute of Physics and Power Engineering (SSC RF—IPPE) using the SVZ-100 lead slowing-down neutron spectrometer. The study focuses on measuring the fission cross sections of americium isotopes 241Am, 242mAm, and 243Am when bombarded by neutrons with energies below 100 keV. The high efficiency of the SVZ-100, facilitated by its substantial working-substance mass (100 t of high-purity lead) and neutron generation through proton irradiation with a 209-MeV accelerator at the INR RAS, enables the investigation of neutron-nuclear processes in microgram samples of radioactive nuclides, which is unattainable in experiments using time-of-flight spectrometry. Unique scientific information is acquired through lead slowing-down neutron spectrometry by collaborative research efforts at the INR RAS and SSC RF—IPPE. This information partially fills gaps or complements existing but often contradictory or insufficient data from experiments conducted on both time-of-flight installations and lead slowing-down neutron spectrometers at other research centers. The results of collaboration of the INR RAS and SSC RF—IPPE are documented in international nuclear data repositories, indicating, in several instances, the need for adjustments to recommended approximating and calculated values. Information is given on some implemented and planned studies on neutron fission cross sections of americium isotopes at other centers following completion of the collaboration of the INR RAS and SSC RF—IPPE. [ABSTRACT FROM AUTHOR]

The fission cross section of Am at neutron energies 0.2 eV-10 keV is measured using an SVZ-100 moderated neutron lead spectrometer at the Institute for Nuclear Research of the Russian Academy of Sciences. The fission resonance integrals and the area and fission width of the allowed resonances are calculated. The results are compared with existing and recommended evaluations. [ABSTRACT FROM AUTHOR]

The cross section for the neutron-induced fission of Am at neutron energies between 0.2 eV and 10 keV was measured by means of a lead slowing-down spectrometer (LSDS-100). The parameters of the intermediate structure in the behavior of the fission strength function were estimated. [ABSTRACT FROM AUTHOR]

The SVZ-100 lead moderation time neutron spectrometer at the Institute of Nuclear Physics of the Russian Academy of Sciences was used to measure the fission cross section for Am in the neutron energy range E = 0.3 eV - 10 keV. The resonance fission integrals and the area and fission width of the resolved resonances were calculated. The properties of the intermediate-structure resonances were evaluated. The results were compared with existing data and recommended evaluations. [ABSTRACT FROM AUTHOR]

The fission cross sections of Cm nuclei for neutron energies 0.1 eV-20 keV have been measured using an SVZ-100 lead moderation time neutron spectrometer at the Institute of Nuclear Research of the Russian Academy of Sciences. The fission resonance integrals have been calculated. The results are compared with the existing data and recommended evaluations. [ABSTRACT FROM AUTHOR]

The cross section for Cm fission induced by neutrons of energy in the range 0.1 eV-20 keV was measured by the neutron lead slowing-down spectrometer (LSDS-100) of the Institute for Nuclear Research (INR, Russian Academy of Sciences, Moscow). The parameters of the resonance area and of the fission width were evaluated for several low-lying s-wave neutron resonances. The parameters of the intermediate structure in the cross section for the subbarrier fusion of Cm nuclei were found. The results obtained in this way were compared with available experimental data and with recommended evaluated data. [ABSTRACT FROM AUTHOR]

The cross section for Cm fission induced by neutrons of energy in the range between 0.07 eV and 20 keV was measured by using the lead slowing-down spectrometer (LSDS-100) of the Institute for Nuclear Research (Russian Academy of Sciences, Moscow). The parameters of the resonance areas were determined for the lowest eight s-wave neutron resonances, and the respective fission widths were evaluated. Also, the parameters of the intermediate structure in the cross section for the subbarrier fission of Cm nuclei were evaluated. The results were compared with available data and recommendations based on evaluations. [ABSTRACT FROM AUTHOR]

The neutron fission cross section of 243Cm for neutron energies 0.03 eV – 20 keV is measured with a neutron spectrometer at the Institute for Nuclear Research of the Russian Academy of Sciences on the basis of the moderation time in lead (SVZ-100). The values of the resonance fission integral and the Westcott factor g(T) are obtained. A comparison is made with existing data and recommended values. A new evaluation of the fission cross section for thermal neutrons is made. [ABSTRACT FROM AUTHOR]

The cross section for 236U fission in the neutron-energy range E n = 0.001–20 keV was measured by using the INR RAS (Institute of Nuclear Research, Russian Academy of Sciences, Moscow) LSDS-100 neutron spectrometer of the lead slowing-down spectrometer type. The resonance fission areas of the resonances at 5.45 eV and 1.28 keV were found, and the fission widths of these resonances were evaluated. The cross section for the 238U( n, f) fission process was measured, and the threshold sensitivity of the LSDS-100 to small values of fission cross sections was estimated. The well-known intermediate structure in the cross section for the neutron-induced subbarrier fission of 236U was confirmed. [ABSTRACT FROM AUTHOR]