排序方式: 共有43条查询结果,搜索用时 0 毫秒
1.
M. I. Krivopustov J. Adam V. Bradnova R. Brandt V. S. Butsev P. I. Golubev V. G. Kalinnikov J. Karachuk B. A. Kulakov E.-J. Langrock G. Modolo M. Ochs R. Odoj A. N. Premyshev V. S. Pronskich Th. Schmidt V. I. Stegailov J. S. Wan V. M. Zupko-Sitnikov 《Journal of Radioanalytical and Nuclear Chemistry》1997,222(1-2):267-270
First experiments on the transmutation of long-lived129I and237Np using relativistic protons of 3.7 GeV are described. Relativistic protons generate in extended Pb-targets substancial neutron fluences. These neutrons get moderated in paraffin and are used for transmutation as follows:129I(n,)130I and237Np(n,)238Np. The isotopes130I (T
1/2-12.36 h) and238Np (T
1/2=2.117 d) were identified radiochemically. One can estimate the transmutation cross-section (n,) in the given neutron field as (129I(n,))=(10±2)b and (237Np(n,))=(140±30)b The experiments were carried out in November 1996 at the Synchrophasotron, LHE, Dubna, Russia. The investigation has been performed at the Laboratory of High Energies, JINR, Dubna. 相似文献
2.
3.
J. Adam K. Katovsky A. Balabekyan V. G. Kalinnikov M. I. Krivopustov H. Kumawat A. A. Solnyshkin V. I. Stegailov S. G. Stetsenko V. M. Tsoupko-Sitnikov W. Westmeier 《Pramana》2007,68(2):201-212
Target-blanket facility ‘Energy + Transmutation’ was irradiated by proton beam extracted from the Nuclotron Accelerator in
Laboratory of High Energies of Joint Institute for Nuclear Research in Dubna, Russia. Neutrons generated by the spallation
reactions of 0.7, 1.0, 1.5 and 2 GeV protons and lead target interact with subcritical uranium blanket. In the neutron field
outside the blanket, radioactive iodine, neptunium, plutonium and americium samples were irradiated and transmutation reaction
yields (residual nuclei production yields) have been determined using γ-spectroscopy. Neutron field's energy distribution
has also been studied using a set of threshold detectors. Results of transmutation studies of 129I, 237Np, 238Pu, 239Pu and 241Am are presented.
相似文献
4.
G. E. Norman V. V. Stegailov A. V. Timofeev 《Journal of Experimental and Theoretical Physics》2011,113(5):887-900
The system of equations of motion of dust particles in a near-electrode layer of a gas discharge has been formulated taking
into account fluctuations of the charge of a dust particle and the features of the nearelectrode layer of the discharge. The
molecular dynamics simulation of the system of dust particles has been carried out. Performing a theoretical analysis of the
simulation results, a mechanism of increasing the average kinetic energy of dust particles in the gas discharge plasma has
been proposed. According to this mechanism, the heating of the vertical oscillations of dust particles is initiated by induced
oscillations generated by fluctuations of the charge of dust particles, and the energy transfer from vertical to horizontal
oscillations can be based on the parametric resonance phenomenon. The combination of the parametric and induced resonances
makes it possible to explain an anomalously high kinetic energy of dust particles. The estimate of the frequency, amplitude,
and kinetic energy of dust particles are close to the respective experimental values. 相似文献
5.
A. R. Balabekyan A. S. Danagulyan J. R. Drnoyan G. H. Hovhannisyan J. Adam V. G. Kalinnikov M. I. Krivopustov V. S. Pronskikh V. I. Stegailov A. A. Solnyshkin P. Chaloun V. M. Tsoupko-Sitnikov S. G. Mashnik K. K. Gudima 《Physics of Atomic Nuclei》2006,69(9):1485-1495
We measure cross sections for residual nuclide formation in the mass range 7 ≤ A ≤ 96 caused by bombardment with protons and deuterons of 3.65-GeV/nucleon energy of enriched tin isotopes (112,118,120,124Sn). The experimental data are compared with calculations by the codes FLUKA, LAHET, CEM03, and LAQGSM03. Scaling behavior
is observed for the whole mass region of residual nuclei, showing a possible multifragmentation mechanism for the formation
of light products (7 ≤ A ≤ 30). Our analysis of the isoscaling dependence also shows a possible contribution of multifragmentation to the production
of heavier nuclides, in the mass region 40 ≤ A ≤ 80.
The text was submitted by the authors in English. 相似文献
6.
The properties of a polyethylene matrix in contact with carbon nanoinclusions, such as carbon nanotubes and graphene plates, are studied via the molecular-dynamics method. Ultimate shear stresses for the polyethylene/graphene interface are calculated, and the effect of the filler aspect ratio on the nanocomposite elastic modulus is considered. 相似文献
7.
G. E. Norman S. V. Starikov V. V. Stegailov 《Journal of Experimental and Theoretical Physics》2012,114(5):792-800
The process of ablation of a gold target by femto- and picosecond laser radiation pulses has been studied by numerical simulations using an atomistic model with allowance for the electron subsystem and the dependence of the ion-ion interaction potential on the electron temperature. Using this potential, it is possible to take into account the change in the physical properties of the ion subsystem as a result of heating of the electron subsystem. The results of simulations reveal a significant difference between the characteristics of metal ablation by laser pulses of various durations. For ablation with subpicosecond pulses, two mechanisms of metal fracture related to the evolution of electronic pressure in the system are established. 相似文献
8.
M. Ochs I. G. Abdullaev I. Adam J. C. Adloff I. G. Bersina V. Bradnova R. Brandt M. Bognitzki V. S. Butsev M. Debeauvais K. K. Dwivedi F. Fernandes S. -L. Guo M. I. Krivopustov B. A. Kulakov E. -J. Langrock G. Modolo R. Odoj V. P. Perelygin A. N. Priemyshev V. S. Pronskich T. Schmidt A. N. Sosnin V. I. Stegailov R. Sudowe P. Vater J. -S. Wan M. Zamani V. M. Zupko-Sitnikov 《Radiation measurements》1997,28(1-6):255-268
Extended targets were irradiated for transmutation studies with relativistic heavy ions. For this, a metal core was surrounded by a paraffin moderator. The metal is either copper or lead and it was irradiated with deuterium, alpha, or carbon beams of 1.5 or 3.7 GeV/u at the SYNCHROPHASOTRON, LHE, JINR, Dubna, Russia. During this irradiation copious amounts of secondary neutrons are produced and studied with SSNTD detectors and radiochemical sensors, for example 139La (n, γ) 140La→β−. The yield of reaction products allows an estimation of secondary neutron fluxes. The yields of all kinds of reactions produced with deuterium and alpha beams obey to some extent the law of “limiting fragmentation”, i.e. they show little influence on the energy and the kind of incoming particles. However, one observes with 44 GeV 12C ions always enhanced nuclear cross-sections induced by secondary particles. This behavior could not be confirmed with theoretical estimations based on the Dubna Cascade Model in its Cascade Evaporation Model version (DCM-CEM). Finally, some results for transmutation studies on 127I and Cu will be presented. 相似文献
9.
F. Křížek V. Wagner J. Adam P. Čaloun V. Henzl D. Henzlová A. Krása A. Kugler M. Majerle M. I. Krivopustov V. I. Stegailov V. M. Tsoupko-Sitnikov 《Czechoslovak Journal of Physics》2006,56(3):243-252
The Neutron Activation Analysis Method was used to study neutron field in a setup consisting of a thick lead target and a
natural uranium blanket. This setup was exposed to 1.5 GeV proton beam from the Nuclotron accelerator. By means of gamma-ray
spectroscopic measurements we determined the yields of various nuclear reactions induced in the radio-chemical sensors. The
data obtained were then compared with the results of a MCNPX simulation. 相似文献
10.
A. R. Balabekyan A. S. Danagulyan J. R. Drnoyan N. A. Demekhina J. Adam V. G. Kalinnikov M. I. Krivopustov V. S. Pronskikh V. I. Stegailov A. A. Solnishkin P. Chaloun V. M. Tsoupko-Sitnikov G. Musulmanbekov 《Physics of Atomic Nuclei》2005,68(2):171-176
The cross sections for (d, xn), (d, pxn), (p, xn), and (p, pxn) reactions on enriched tin isotopes are obtained at a projectile energy of 3.65 GeV per nucleon. The yields in the energy range 0.66–8.1 GeV are analyzed with resort to experimental data obtained previously. Experimental data are compared with the results of theoretical calculations performed within the cascade-evaporation model. The dependence of the yields on the number of emitted neutrons, the projectile type, and the isotopic composition of a target is investigated. The cross sections for the (p, xpyn) reactions on a 120Sn target are presented at a primary-proton energy of 0.66 GeV. 相似文献