Results 1 - 10 of 156
Results 1 - 10 of 156. Search took: 0.023 seconds
|Sort by: date | relevance|
[en] The ternary fission of 238-256Cf even-A isotopes is studied in the framework of the three-cluster model within the spherical approximation. The study is confined to those decays in which the accompanied light charged particle is of mass A = 10. The most probable ternary fission path is obtained as the one that has a peak in the Q-value and a minimum in the driving potential, with respect to the mass and charge asymmetries. Assuming both equatorial and collinear configurations of the different emissions of the light charged particles with A = 10, the ternary fission of 252Cf is found to be most favored with 10Be. The predicted favorable fragmentation channels of the 10Be-accompanied ternary fission of 238-256Cf, even-A, isotopes are discussed in detail. The closed-shell structure of the produced heaviest fragment is found to play a key role for the detected most favorable channels. A nucleus with a closed neutron shell or even doubly closed shell always appears as the heaviest nucleus in the favored channel of the ternary fission of all mentioned isotopes. As the isospin asymmetry of the isotope increases, the width of its cold fission valley around the symmetric mass region decreases, with more shifting towards the centre of the symmetric region. Neither the most favorable ternary emissions nor the behavior of the ternary fragmentation potential changed with the type of nuclear interaction potential (Yukawa, folding potential with Migdal force, and proximity 77). Also, almost no change is observed according to the method of emission of the fragments (equatorially or collinearly) or when the calculations are performed without inserting the nuclear interaction potential. (author)
[en] A new approach to the interpretation of the process of spontaneous fission of heavy nuclei is suggested. It is based on nuclear physics data which are obtained in heavy ion collisions. The process of spontaneous fission consists of three sequential stages: clusterization of the valent nucleons of a heavy nucleus into a light nucleus-cluster, which leads to the formation of a dinuclear system; evolution of the dinuclear system which proceeds by nucleon transfer from the heavy to light nucleus; and decay of the dinuclear system from the equilibrium configuration into two fragments.
[ru]Предлагается новый подход к интерпретации процесса спонтанного деления тяжелых ядер, который опирается на данные, полученные в ядерно-физических исследованиях с тяжелыми ионами. Спонтанное деление включает в себя три последовательно протекающие стадии: кластеризацию валентных нуклонов тяжелого ядра в легкое ядро-кластер, в результате чего возникает двойная ядерная система; эволюцию двойной ядерной системы, протекающую путем передачи нуклонов от тяжелого к легкому ядру, и распад двойной системы из равновесной конфигурации на два ядра-осколка.
[en] Design of a hybrid gaseous detector for slow neutrons. Construction of the hybrid gaseous detector and tests with a 52Cf isotope and the MC-50 cyclotron. Designs, constructions, and tests for hybrid scintillators using various neutron sensitive materials (2nd year). Application to development of detectors for high energy physics (2nd year). Practical R and Ds for applications to medical and industrial purposes (3rd year)
[en] Gas catchers allow the transformation of radioactive recoils from various sources into a good optical quality low-energy radioactive beam that is then available for experiments at low-energy or for further acceleration. The CARIBU project uses such a large gas catcher to create beams of neutron-rich isotopes from a Californium source for post-acceleration through the ATLAS superconducting linac to open new research opportunities for nuclear structure physics and astrophysics. The RF gas catcher developed at Argonne has now demonstrated operation at the high intensity required for this application.
[en] One hundred and five isotopes of the transuranium elements neptunium, plutonium, americium, curium, berkelium, and californium have been observed so far; the discovery of these isotopes is described. For each isotope a brief summary of the first refereed publication, including the production and identification method, is presented
[en] This standard is applicable to operations with the following: 23793Np, 2393894Pu, 24094Pu, 24194Pu, 24294Pu, 24195Am, 242m95Am, 24395Am, 24396Cm, 24496Cm, 24596Cm, 24796Cm, 24998Cf and 25198Cf. Subcritical mass limits are presented for isolated fissionable units. The limits are not applicable to interacting units
[en] Berkelium, californium, einsteinium, and fermium are currently produced in the High Flux Isotope Reactor (HFIR) and recovered in the Radiochemical Engineering Development Center (REDC) at the Oak Ridge National Laboratory (ORNL). All the isotopes are used for research. In addition, 252Cf, 253Es, and 255Fm have been considered or are used for industrial or medical applications. ORNL is the sole producer of these transcurium isotopes in the western world. A wide range of actinide samples were irradiated in special test assemblies at the Fast Flux Test Facility (FFTF) at Hanford, Washington. The purpose of the experiments was to evaluate the usefulness of the two-group flux model for transmutations in the special assemblies with an eventual goal of determining the feasibility of producing macro amounts of transcurium isotopes in the FFTF. Preliminary results from the production of 254gEs from 252Cf will be discussed. 14 refs., 5 tabs
[en] Electrodepositions of californium isotopes were successfully performed at Oak Ridge National Laboratory involving two different types of deposition solutions, ammonium acetate and isobutanol. A californium product that was decay-enriched in 251Cf was recovered for use in super-heavy element research. The californium was purified and then electrodeposited using the isobutanol method onto thin titanium foils for use at the Joint Institute for Nuclear Research. An ammonium acetate method was used to produce a deposition containing 1.7 ± 0.1 Ci of 252Cf onto a stainless steel substrate. This is the largest single electrodeposition of 252Cf ever prepared. (author)