Abstract:A detailed description of photofission process at intermediate energies (200 to 1000 MeV) is presented. The study of the reaction is performed by a Monte Carlo method which allows the investigation of properties of residual nuclei and fissioning nuclei. The information obtained indicate that multifragmentation is negligible at the photon energies studied here, and that the symmetrical fission is dominant. Energy and mass distributions of residual and fissioning nuclei were calculated.
“…It is important to emphasize that the CRISP code has been used to simulate nuclear reactions of several kinds, such as those induced by protons [33][34][35], photons [19,27,[36][37][38], electrons [39,40], or hypernuclei [21,41,42], with energies from 50 MeV up to 3.5 GeV, and on nuclei with masses going from A = 12 up to A = 240 and with several observables: spallation products, strange particles, fission products, hyperon-decay particles, fragment mass, and atomic number distributions. The code has been applied in the study for development of nuclear reactors [43][44][45].…”
In this work we present the results for the investigation of intermediate-mass fragment (IMF) production with the proton-induced reaction at 660 MeV on 238 U and 237 Np target. The data were obtained with the LNR Phasotron U-400M Cyclotron at Joint Institute for Nuclear Research (JINR), Dubna, Russia. A total of 93 isotopes, in the mass range of 30 < A < 200, were unambiguously identified with high precision. The fragment production cross sections were obtained by means of the induced-activation method in an off-line analysis. Mass-yield distributions were derived from the data and compared with the results of the simulation code CRISP for multimodal fission. A discussion of the superasymmetric fragment production mechanism is also given.
“…It is important to emphasize that the CRISP code has been used to simulate nuclear reactions of several kinds, such as those induced by protons [33][34][35], photons [19,27,[36][37][38], electrons [39,40], or hypernuclei [21,41,42], with energies from 50 MeV up to 3.5 GeV, and on nuclei with masses going from A = 12 up to A = 240 and with several observables: spallation products, strange particles, fission products, hyperon-decay particles, fragment mass, and atomic number distributions. The code has been applied in the study for development of nuclear reactors [43][44][45].…”
In this work we present the results for the investigation of intermediate-mass fragment (IMF) production with the proton-induced reaction at 660 MeV on 238 U and 237 Np target. The data were obtained with the LNR Phasotron U-400M Cyclotron at Joint Institute for Nuclear Research (JINR), Dubna, Russia. A total of 93 isotopes, in the mass range of 30 < A < 200, were unambiguously identified with high precision. The fragment production cross sections were obtained by means of the induced-activation method in an off-line analysis. Mass-yield distributions were derived from the data and compared with the results of the simulation code CRISP for multimodal fission. A discussion of the superasymmetric fragment production mechanism is also given.
“…With formula (9) it is now possible to calculate the probability of fission, P f , at each step of the evaporation/fission competition process. Whenever the fission channel is chosen, two fragments are formed [39,40], the heaviest one having mass and atomic numbers, A H and Z H , respectively, is sorted according to a probability distribution given by the statistical scission model (SSM) from Brosa et al [41]. The lighter fragment has mass and atomic numbers given, respectively, by A L = A F − A H and Z L = Z F − Z H .…”
The fragments produced in nuclear reactions for accelarator driven systems (ADS) operation form elements that can have effects on the structure of the reactor. In this regard, the calculation of fragment distributions gives important information for the development of ADS. To obtain those distributions, the Monte Carlo (MC) method is an important tool, and in this work we describe calculations of fragment distributions through a MC code for reactions initiated by intermediate- and high-energy protons and photons on actinide and preactinide nuclei. We study the production of fragments through spallation and fission reactions. The results show good qualitative agreement with experimental data.
“…A diferença fundamental está no fato dos resultados serem nitidamente melhores, com alguns bons acordos tanto de forma como de seção de choque total para as primeiras três parábolas. Um acordo inferior porém valioso também se nota para os produtos 79 Au, 78 Pt e 77 Ir.…”
Section: Fotofissão E Spallationunclassified
“…[51] A energias intermediárias e altas, os valores de posição e largura para cada modo de fissão, como obtidos de um ajuste direto da expressão (2.52) podem ser alterados em virtude das distribuições de massa e número atômico do núcleo fissionante [77,78,79]. Os efeitos da distribuição de massa do núcleo fissionante na descrição dos modos de fissão já foram estudados em reações entre 238 U e deutério a 1 GeV/nucleon [77], e podem também ter efeitos sobre os resultados de reações com fótons e prótons a energias intermediárias [20,25].…”
Section: Distribuição De Massa De Fragmentos De Fissãounclassified
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