248 research outputs found
Fixed-Point Arithmetic in FPGA
Arithmetic operations are among the most frequently-used operations in contemporary digital integrated circuits. Various structures have been designed, utilizing different features of IC architectures. Nevertheless, there are very few studies that consider the design of arithmetic operations in Field Programmable Gate Arrays (FPGAs), a re-programmable type of digital integrated circuit. This text compares the results achieved when implementation of basic fixed-point arithmetic units in FPGA.
Efeitos do treinamento aquático em posição vertical: diferentes aplicações e suas respostas fisiológicas
It is demonstrated that available experimental information on photon strength functions
(PSFs) at energies below about 10 MeV is far from desired. Problems that occur during the
extraction of PSFs from (n, γ), (γ,γ′),
and 3He-induced reactions are discussed
First Measurement of 72Ge(n,γ) at n_TOF
9th European Summer School on Experimental Nuclear AstrophysicsThe slow neutron capture process (s-process) is responsible for producing about half of the elemental abundances heavier than iron in the universo
Determination of the electromagnetic character of soft dipole modes solely based on quasicontinuous gamma spectroscopy
We show that the combined analysis of the quasicontinuous gamma spectra from
the (He-3,alpha) and the (n-thermal,2gamma) reactions gives the possibility to
measure the electromagnetic character of soft dipole resonances. Two-step
gamma-cascade spectra have been calculated, using level densities and radiative
strength functions from the (He-3,alpha gamma) reaction. The calculations show
that the intensity of the two-step cascades depends on the electromagnetic
character of the soft dipole resonance under study. The difference reaches
40-100% which can be measured experimentally.Comment: 9 pages including 1 table and 2 figure
Recent results in nuclear astrophysics at the n_TOF facility at CERN
The neutron time of flight (n_TOF) facility at CERN is a spallation source characterized by a white neutron spectrum. The innovative features of the facility, in the two experimental areas, (20 m and 185 m), allow for an accurate determination of the neutron cross section for radioactive samples or for isotopes with small neutron capture cross section, of interest for Nuclear Astrophysics. The recent results obtained at n_TOF facility are presented
Thermal and electromagnetic properties of 166-Er and 167-Er
The primary gamma-ray spectra of 166-Er and 167-Er are deduced from the
(3-He,alpha gamma) and (3-He,3-He' gamma) reaction, respectively, enabling a
simultaneous extraction of the level density and the gamma-ray strength
function. Entropy, temperature and heat capacity are deduced from the level
density within the micro-canonical and the canonical ensemble, displaying
signals of a phase-like transition from the pair-correlated ground state to an
uncorrelated state at Tc=0.5 MeV. The gamma-ray strength function displays a
bump around E-gamma=3 MeV, interpreted as the pygmy resonance.Comment: 21 pages including 2 tables and 11 figure
High precision measurement of the radiative capture cross section of 238U at the n-TOF CERN facility
The importance of improving the accuracy on the capture cross-section of 238U has been addressed
by the Nuclear Energy Agency, since its uncertainty significantly affects the uncertainties of key design
parameters for both fast and thermal nuclear reactors. Within the 7th framework programme ANDES of the
European Commission three different measurements have been carried out with the aim of providing the
238U(n,γ) cross-section with an accuracy which varies from 1 to 5%, depending on the energy range. Hereby
the final results of the measurement performed at the n TOF CERN facility in a wide energy range from 1 eV
to 700 keV will be presented
Level density and thermal properties in rare earth nuclei
A convergent method to extract the nuclear level density and the gamma-ray
strength function from primary gamma-ray spectra has been established.
Thermodynamical quantities have been obtained within the microcanonical and
canonical ensemble theory. Structures in the caloric curve and in the heat
capacity curve are interpreted as fingerprints of breaking of Cooper pairs and
quenching of pairing correlations. The strength function can be described using
models and common parameterizations for the E1, M1 and pygmy resonance
strength. However, a significant decrease of the pygmy resonance strength at
finite temperatures has been observed.Comment: 15 pages including 8 figures. Proceedings article for the conference
Nuclear Structure and Related Topics, Dubna, Russia, June 6-10, 200
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