258 research outputs found
High-energy threshold reaction rates on 0.8 GeV proton-irradiated thick Pb-target
This works presents results of activation-aided determination of threshold
reaction rates in 92 209Bi, natPb, 197Au, 181Ta, 169Tm, natIn, 93Nb, 64Zn,
65Cu, 63Cu, 59Co, 19F, and 12C samples and in 121 27Al samples. All the samples
were aligned with the proton beam axis inside and outside the demountable 92-cm
thick Pb target of 15-cm diameter assembled of 23 4-cm thick discs. The samples
were placed on 12 target disks to reproduce the long axis distribution of
protons and neutrons. In June 2006, the target was exposed for 18 hours to a
800-MeV proton beam extracted from the ITEP U-10 accelerator. The proton
fluence and the proton beam shape were determined using the 27Al(p,x)7Be
monitor reaction. The reaction rates were determined by the direct
gamma-spectrometry techniques. In total, 1196 gamma-spectra have been measured,
and about 1500 reaction rates determined. The measured reaction rates were
simulated by the MCNPX code using the following databases: ENDF/B6 for neutrons
below 20 MeV, MENDL2 for 20-100 MeV neutrons, and MENDL2P for proton cross
sections up to 200 MeV. An acceptable agreement of simulations with
experimental data has been found.Comment: 4 pages, 5 figures, 3 tables, only pdf file, to be published in Proc.
Int. Conf. on Nucl. Data for Sci. and Technology (ND2007), Nice, France,
April 22-27, 200
Residual nuclide formation in 206,207,208,nat-Pb and 209-Bi induced by 0.04-2.6 GeV Protons as well as in 56-Fe induced by 0.3-2.6 GeV Protons
5972 independent and cumulative yields of radioactive residuals nuclei have
been measured in 55 thin 206,207,208,nat-Pb and 209-Bi targets irradiated by
0.04, 0.07, 0.10, 0.15, 0.25, 0.6, 0.8, 1.2, 1.4, 1.6, and 2.6 GeV protons.
Besides, 219 yields have been measured in 0.3, 0.5, 0.75, 1.0, 1.5, and 2.6 GeV
proton-irradiated 56-Fe target. The protons were extracted from the ITEP U-10
synchrotron. The measured data are compared with experimental results obtained
elsewhere and with theoretical calculations by LAHET, MCNPX, CEM03, LAQGSM03,
CASCADE, CASCADO, and LAHETO codes. The predictive power was found to be
different for each of the codes tested, but was satisfactory on the whole in
the case of spallation products. At the same time, none of the codes can
de-scribe well the product yields throughout the whole product mass range, and
all codes must be further improved.Comment: 4 pages, 4 figures, 2 tables, only pdf file, to be published in Proc.
Int. Conf. on Nucl. Data for Sci. and Technology (ND2007), Nice, France,
April 22-27, 20
Russian representation of the Chinese national character (second half of XIX - early XX cen)
В статье рассматриваются особенности становления и развития представлений русского общества XIX – начала XX вв. о Китае и его жителях. Целью исследования стал анализ специфики представлений русских о китайском национальном характере. Исследование выполнено в рамках научного направления – имагологии.The article describes the formation and development specifics of the views about China and its inhabitants in Russian society of the 19th – early 20th century. The aim of the study was to analyze the specifics of Russian representations of the Chinese national character. The research is performed within the framework of the imagology research prospect
Verification of high-energy transport codes on the basis of activation data
Nuclide production cross sections measured at ITEP for the targets of nat-Cr,
56-Fe, nat-Ni, 93-Nb, 181-Ta, nat-W, nat-Pb, 209-Bi irradiated by protons with
energies from 40 to 2600 MeV were used to estimate the predictive accuracy of
several popular high-energy transport codes. A general agreement of the ITEP
data with the data obtained by other groups, including the numerous GSI data
measured by the inverse kinematics method was found. Simulations of the
measured data were performed with the MCNPX (Bertini and ISABEL options),
CEM03.02, INCL4.2+ABLA, INCL4.5+ABLA07, PHITS, and CASCADE.07 codes. Deviation
factors between the calculated and experimental cross sections have been
estimated for each target and for the whole energy range covered by our
measurements. Two-dimensional diagrams of deviation factor values were produced
for estimating the predictive power of every code for intermediate, not
measured masses of nuclei-targets and bombarding energies of protons. Further
improvements of all tested here codes are recommended. In addition, new
measurements at ITEP of nuclide yields from a 208-Pb target irradiated by 500
MeV protons are presented. A good agreement between these new data and the GSI
measurements obtained by the inverse kinematics method was foundComment: 31 pages, 18 figures, 6 tables, only pdf, LANL Report LA-UR-11-02704,
Los Alamos (2011), submitted to Phys. Rev.
Multilevel Parallelization: Grid Methods for Solving Direct and Inverse Problems
In this paper we present grid methods which we have developed for solving direct and inverse problems, and their realization with different levels of optimization. We have focused on solving systems of hyperbolic equations using finite difference and finite volume numerical methods on multicore architectures. Several levels of parallelism have been applied: geometric decomposition of the calculative domain, workload distribution over threads within OpenMP directives, and vectorization. The run-time efficiency of these methods has been investigated. These developments have been tested using the astrophysics code AstroPhi on a hybrid cluster Polytechnic RSC PetaStream (consisting of Intel Xeon Phi accelerators) and a geophysics (seismic wave) code on an Intel Core i7-3930K multicore processor. We present the results of the calculations and study MPI run-time energy efficiency
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