共查询到20条相似文献,搜索用时 15 毫秒
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Using the delayed coincidence method and the reaction19F(α, pγ)22Ne at 10.80 MeV alpha energy, the lifetime of the 5.14 MeV state in22Ne is determined to beτ=0.84 nsec±10%. 相似文献
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High resolution measurements of K X-ray intensities are combined with total X-ray production cross sections and charge-state dependent fluorescence yields to obtain production cross sections for ions having one K and multiple L-shell vacancies. Deduced charge state distributions are compared with those determined from inelastic scattering studies and are used to set limits on the probability of having an electron in an excited state at the time of X-ray emission. 相似文献
5.
Marco Fernández Ghiraldo Murillo Jesús Ramírez Olga Avila S.E. Darden M.C. Rozak J.L. Foster B.P. Hichwa P.L. Jolivette 《Nuclear Physics A》1981,369(3):425-452
Cross-section and analyzing power angular distributions have been measured for 20Ne(p, p)20Ne and 20Ne(p, p1)20Ne1(1.63 MeV) for proton energies between 3.7 and 7.9 MeV. The measurements were made in 25 keV intervals between 3.7 and 4.4 MeV, and in 10 keV intervals over most of the region between 4.4 and 7.9 MeV. A phase-shift analysis of the elastic-scattering data has yielded resonance parameters for thirty-three levels in 21Na in the excitation energy region 6.0–9.9 MeV. Some of the strong even-parity resonances can be understood within the framework of the Nilsson model or the shell model. These resonances are also predicted by a macroscopic coupled-channels calculation involving rotational excitation of the 2+ and 4+ states of 20Ne. 相似文献
6.
K. W. Schmid S. Krewald Amand Faessler L. Satpathy 《Zeitschrift für Physik A Hadrons and Nuclei》1974,271(2):149-159
Multi-Configuration-Hartree-Fock (MCHF) calculations with angular momentum projection before the variation of the internal degrees of freedom have been performed for the nuclei20Ne and22Ne. This procedure yields different correlated intrinsic states for the different members of a rotational band. Thus the angular momentum dependence of correlations has been studied. Experimentally, the ground state spectra of20Ne and22Ne show properties similar to the phase transitions observed in some rare earth nuclei which have been well reproduced through the present calculations. The calculated spectra andBE2-values show a significant improvement compared to the ones obtained by variation before the angular momentum projection is effected. 相似文献
7.
We present an analysis of π-20Ne elastic scattering at intermediate energy basing on the α+16O model of the 20Ne nucleus and in the framework of Glauber multiple scattering theory. Satisfactory agreement with the general features of the experimental data of pion elastic scattering on the neighboring 4N-type nuclei is obtained without any free parameters. Compared with the experimental angular distributions of pion elastic scattering on 12C, 16O, 24Mg, and 28Si nuclei, the diffractive patterns and the positions of the dips and peaks in the angular distributions of π-20Ne elastic scattering are reasonably predicted by the calculations. 相似文献
8.
The data on the excitation functions of20Ne(16O,12C)24Mg,20Ne(16O,12C)24Mg*(1.37, 2+),20Ne(16O,12C)24Mg*(4.12, 4++4.24, 2+) +20Ne(16O,12C*(4.44, 2+))24Mg,20Ne(16O,12C)24Mg*(6.01, 4++6.43, 0+),20Ne(16O,20Ne)16O,20Ne(16O,20Ne*(1.63, 2+))16O, and20Ne(16O,20Ne*(4.25, 4+))16O reactions atθ lab=13° fromE c.m.=22.8 to 38.6 MeV have been subjected to a statistical analysis comprising of the calculations of the distribution of cross sections, deviation functions, cross-correlation functions, summed excitation functions, cross-channel correlation coefficients and coherence widths. The analysis confirms the existence of nonstatistical structures atE c.m.=24.6, 27.8, 31.7 and 35.5 MeV, and identifies a new structure of the same nature atE c.m. =25.6 MeV. 相似文献
9.
Ramen Majumdar 《Zeitschrift für Physik A Hadrons and Nuclei》1993,345(3):293-295
The distribution of the 1g 9/2 proton state of the41Sc has been obtained within the framework of the coreparticle coupling model scheme. The theoretical distribution pattern of this high-spin proton orbital has been compared with the recent high resolution experimental works performed on the40Ca target nucleus. The results obtained in the work has also been compared with the other existing theoretical results. 相似文献
10.
Z. Elekes Zs. Dombrádi A. Saito N. Aoi H. Baba K. Demichi Zs. Fülöp J. Gibelin T. Gomi H. Hasegawa N. Imai M. Ishihara H. Iwasaki S. Kanno S. Kawai T. Kishida T. Kubo K. Kurita Y. Matsuyama S. Michimasa T. Minemura T. Motobayashi M. Notani T. K. Ohnishi H. J. Ong S. Ota A. Ozawa H. K. Sakai H. Sakurai S. Shimoura E. Takeshita S. Takeuchi M. Tamaki Y. Togano K. Yamada Y. Yanagisawa K. Yoneda 《The European physical journal. Special topics》2007,150(1):99-102
This paper reports on the 1H(28Ne,28Ne) and 1H(28Ne,27Ne)
reactions studied at intermediate energy using a liquid hydrogen target. From
the cross section populating the first 2+ excited state of 28Ne, and using the previously
determined B(E2) value, the neutron quadrupole transition matrix element has been
calculated to be Mn=13.8 ±3.7 fm2.
In the neutron knock-out reaction, two low-lying excited states were populated in 27Ne.
Only one of them can be interpreted by the sd shell model while the additional state
may intrude from the fp shell. These experimental observations
are consistent with the presence of fp shell configurations at low excitation energy
in 27,28Ne nuclei caused by a vanishing N=20 shell gap at Z=10. 相似文献
11.
P. -T. Ong Y. -X. Yang Q. -R. Li 《The European Physical Journal A - Hadrons and Nuclei》2009,41(2):229-234
The ground state of 20Ne is described as the clustering structure of + 16
O . The cluster wave function with an analytical and simple form is presented. Based on this model, the intermediate-energy
proton- 20Ne elastic scattering is calculated and compared with the experimental data. 相似文献
12.
Mitochondrial oxygen tension can be measured in vivo by means of oxygen-dependent quenching of delayed fluorescence of protoporphyrin IX (PpIX). Here we demonstrate that mitochondrial PO(2) (mitoPO(2)) can be measured in the skin of a rat after topical application of the PpIX precursor 5-aminolevulinic acid (ALA). Calibration of mitoPO(2) measurements was done by comparison with simultaneous measurements of the cutaneous microvascular PO(2) This was done under three different conditions: in normal skin tissue, in nonrespiration skin tissue due to the application of cyanide, and in anoxic skin tissue after the ventilation with 100% nitrogen. The results of this study show that it is feasible to measure the mitoPO(2) after the topical application of ALA cream by means of the PpIX-triplet state lifetime technique. 相似文献
13.
N. Perrin C. Bourgeois A. Korichi M. Pautrat H. Sergolle N. Barré C. Vieu N. Benouaret J. Vanhorenbeeck 《Zeitschrift für Physik A Hadrons and Nuclei》1997,359(4):373-376
The g factors of three high spin isomers in 187,189,191Au have been measured, using the time differential perturbed angular distributions. The reactions used and the results obtained for the g factors and the lifetimes are: 172Yb(19F, 4nγ) 187Au, g (31/2- or 35/2-) = 0.25 (3), T1/2 = 102 (5) ns; 181Ta ( 12C, 4nγ) 189Au, g (31/2+) = 0.42 (2), T1/2 = 242 (10) ns; and 176Yb(19F, 4nγ) 191Au, g (31/2+) = 0.42 (3) T1/2 = 402 (20) ns. These results show that the structure of these isomers is consistent with a 1 proton, 2 neutrons structure. The experimental set-up was cheked by measuring the g factor of the Coulomb excited 197 keV, T1/2 = 89.3 ns level of the 19F beam stopped in the lead backing. 相似文献
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The current status of the measurements of the neutron lifetime has been analyzed. The problem of experimental data discrepancy
has been analyzed and systematic errors of some experiments have been found out. The corrected table of measurements is given
and a new world average value of neutron lifetime 879.9 ± 0.9 s is presented. 相似文献
15.
A.J. Rutten A. Holthuizen J.A.G. De Raedt W.A. Sterrenburg G. Van Middelkoop 《Nuclear Physics A》1980,344(2):294-306
The g-factor and mean lifetime of the first-excited 2+ state at 1.67 MeV in 20O have been determined by means of a plunger set-up. The state was populated by the 3H(18O, pγ)20O reaction at . The analysis of p-γ anisotropies as a function of flight path of the recoiling ion in vacuum leads to a value for the g-factor of |g| = 0.352±0.015 and to a mean life of τ = 10.7±0.4 ps. 相似文献
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A. E. Kramida G. Nave 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2006,37(1):1-21
All observed spectral lines of Ne III in the
range 204 ? to 36 μm (277 cm-1 to 490000 cm-1) have been
compiled and critically evaluated. 57 visible and ultraviolet lines of Ne
III have been precisely measured using Fourier transform spectroscopy. An
optimized level scheme has been derived from the total list of observed
lines. Relative positions of about 180 out of a total of 226 previously
known energy levels of Ne III have been determined with improved accuracy
compared to previous studies. Excitation energies of almost all excited
levels have been revised by (1.5–2.0) cm-1. 127 precise wavelength
standards in the region 210 ? to 2900 ? have been derived. Concepts
of error current and covariance matrix have been implemented in a computational algorithm that permits one
to derive the uncertainties of Ritz wavelength standards obtained from a set
of least-squares-optimized energy levels. Nine new energy levels have been
found, and 16 new transitions have been identified in the extreme
ultraviolet region. The ionization potential has been increased by
4.5 cm-1. The new value is
(
(
). 相似文献
18.
J.A.J. Hermans G.A.P. Engelbertink L.P. Ekström H.H. Eggenhuisen M.A. Van Driel 《Nuclear Physics A》1977,284(2):307-328
Mean lives in the range 1–20 ps of low-lying states of 13C, 16N, 20O and 36Cl have been measured with the Doppler-shift attenuation method by heavy-ion bombardment of 2H and 3H targets. The recoils are slowed down in Mg, Al, Cu, Ag and Au. The γ-ray patterns are observed with a large Ge(Li) detector at 0° in coincidence with protons; for 13C the patterns are measured in singles with a Compton-suppression spectrometer. Analysis of the γ-ray patterns with 4He-scaled stopping power data of Northcliffe and Schilling yields the following results: 13C, τm(3.85 MeV) = 12.6 ± 0.3ps; 16N, τm(0.40 MeV) = 5.1 ± 0.3 ps; 20O, τm(1.67 MeV) = 9.8 ± 0.7 ps; 36Cl, τm(0.79 MeV) = 19.9 ± 1.7 ps, τm(1.16 MeV) = 9.2 ± 0.6 ps and τm(1.60 MeV) = 0.94 ± 0.06 ps. A comparison with results obtained with the recoil-distance method shows agreement to about 10 %, with a slight tendency to somewhat longer lifetimes for the recoil-distance technique. The above stopping power is also used to reanalyze our previously published measurements. The new mean lives differ less than 4.5 % from the previous results. 相似文献
19.
The high-energy tail of the , 2425 keV state in 21Na, bound by 7 keV against proton decay, has been observed in the 20Ne (p,γ)21Na reaction at Ep=0.5?1.5 MeV. The observed excitation function is consistent with a single-level Breit-Wigner shape with Γγ=0.31±0.07 eV at Ex = 2425 keV. 相似文献
20.
V. Conte L. De Nardo P. Colautti A. Ferretti B. Grosswendt M. Lombardi M. Poggi S. Canella D. Moro G. Tornielli 《Radiation measurements》2010,45(10):1213-1216
The STARTRACK experimental set-up, mounted on the +50° beam line of the Tandem-Alpi particle accelerator of Legnaro National Laboratories, has been conceived to give an experimental basis to nanodosimetric calculations. STARTRACK is based on a detection system able to measure ionization cluster distributions in a 20 nm propane site with a resolution of one ionization. The experimental layout has been designed to minimize pile-up distortions. The background noise is filtered by off-line dedicated software. Electron cluster distribution of 20 MeV protons has been measured. Monte Carlo data and experimental data are pretty well consistent. 相似文献