International Nuclear Information System (INIS)

Nuclear shape changes can bring about rapid changes in nuclear properties. That such vibrational #-># symmetric rotor #-># asymmetric nucleus changes may be present in the A approximately 100 region is suggested by rapid, low-energy level density changes and unexpected #beta#-decay rate changes in several series of odd-odd and odd-mass fisions product nuclei. In order to define the nature of these nuclei we have performed measurements on a series of nuclei using JOSEF and Lohengrin mass separators, fast-chemistry, and n-capture #gamma#-ray techniques. Here we summarize the several features we find.

International Nuclear Information System (INIS)

The #beta# decay half-lives of neutron-rich isotopes with Z=24-28 are calculated in the QRPA with a Gamow-Teller residual interaction. For odd-mass and odd-odd systems QRPA phonon correlations are introduced to quasiparticle transitions in first-order perturbation. The calculated half-lives agree very well with the experimental values. For later application of this model to nuclei far from stability, we have examined the dependence of the calculated half-lives on the model parameters. (orig.).

International Nuclear Information System (INIS)

The main features and advantages of a new low energy nuclear spectroscopic method, the in-beam spectroscopy are described. Results of in-beam spectroscopic experiments performed at the Institute of Nuclear Research (ATOMKI, Debrecen, Hungary) are summarized. Gamma spectra of in-beam produced odd-odd nuclei were measured, gamma-energies were determined. Measurement of gamma-gamma coincidences led to the construction of energy level schemes of the investigated nuclei. Internal conversion electron spectroscopy was used to determine the multipolarities of transitions. A few spectra and level schemes are presented to illustrate the review. Theoretical interpretation of experimental results are briefly summarized. (D.Gy.).

Energy Technology Data Exchange (ETDEWEB)

Laser spectroscopy measurements have been performed on neutron-deficient and stable Ir isotopes using the COMPLIS experimental setup installed at ISOLDE-CERN. The radioactive Ir atoms were obtained from successive decays of a mass-separated Hg beam deposited onto a carbon substrate after deceleration to 1kV and subsequently laser desorbed. A three-color, two-step resonant scheme was used to selectively ionize the desorbed Ir atoms. The hyperfine structure (HFS) and isotope shift (IS) of the first transition of the ionization path 5d{sup 7}6s{sup 24}F{sub 9/2}{yields}5d{sup 7}6s6p{sup 6}F{sub 11/2} at 351.5nm were measured for {sup 182-189}Ir, {sup 186}Ir{sup m} and the stable {sup 191,193}Ir. The nuclear magnetic moments {mu}{sub I} and the spectroscopic quadrupole moments Q{sub s} were obtained from the HFS spectra and the change of the mean square charge radii from the IS measurements. The sign of {mu}{sub I} was experimentally determined for the first time for ...

International Nuclear Information System (INIS)

... energy levels intermediate mass nuclei isotopes nuclei odd-even nuclei

Energy Technology Data Exchange (ETDEWEB)

Using Gammasphere data on prompt gamma rays from spontaneous fission of 252Cf, we propose energy-level schemes for 110,111,112, & 113Rh (Z=45). The fission-gamma data complement earlier studies of others on beta decay of fission products in that prompt fission gammas mainly populate yrast or near-yrast levels, while beta decay populates lower-spin levels. For the odd-A rhodium nuclei studied here, their ground bands and collective sidebands are compared with model calculations using triaxial-shaped nucleus with one odd quasi-proton. The energies and E2 transition rates are best fit by a shape slightly to the prolate side of maximum triaxiality, namely, gamma = 28 deg. The model calculations also show a K=1/2+ band with energies not in good agreement with a corresponding experimental band. The experimental 1/2+ band is regarded as an intruder band from a prolate-driving proton orbital 1/2[431] above the Z=50 closed shell. This intruder band, seen in other odd-A ...

International Nuclear Information System (INIS)

Low-lying nuclear energy levels in "1"1"0In and "1"1"2In were determined from de-excitation #gamma#-rays produced with "1"0"7Ag(#alpha#,n#gamma#)-"1"1"0In, "1"0"8Pd("6Li,4n#gamma#)"1"1"0In, "1"0"9Ag(#alpha#,n#gamma#)"1"1"2In and "1"1"0Pd("6Li,4n#gamma#)"1"1"2In reactions. In addition, the "1"1"4In energy level structure was investigated with the "1"1"0Pd("7Li,3n#gamma#)"1"1"4In reaction. Properties of de-excitation #gamma#-rays were determined from #gamma#-#gamma# coincidence, excitation, and angular distribution measurements conducted with Ge(Li) and Ge(intr.) #gamma#-ray detectors. A sequence of intraconnected levels in each of "1"1"0,"1"1"2,"1"1"4In were assigned to the (#pi#g"-"1/sub 9/2/, #nu#h/sub 11/2/) configuration. For the "1"1"0,"1"1"2,"1"1"4In energy level schemes a model calculation has been performed using the pairing-plus-quadrupole model, which reproduced states of the (#pi#g"-"1/sub 9/2/, #nu#h/sub 11/2/) multiplets quite well. A value of the proton-neutron coupling ...

International Nuclear Information System (INIS)

... capture radioisotopes energy levels excited states intermediate mass nuclei

International Nuclear Information System (INIS)

Mass distributions of fragments in the low-energy fission of nuclei from "1"8"7Ir to "2"1"3At have been analysed. This analysis has shown that shell effects in symmetric-mode fragment mass yields from the fission of pre-actinide nuclei could be described if one assumes the existence of two strongly deformed neutron shells in the arising fragments with neutron numbers N_1#approx#52 and N_2#approx#68. A new method has been proposed for quantitatively describing the mass distributions of the symmetric fission mode for pre-actinides with A#approx#180-220. (orig.)

Energy Technology Data Exchange (ETDEWEB)

Detailed level and decay schemes are presented for the nuclei of the A = 101 mass chain. The level properties obtained from decay and reaction experiments are shown in the drawings. Experimental methods, references, and comments are given in the text.

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The mass asymmetry of fragments from nuclear fission of heavy nuclei is reviewed. While mass asymmetry is a common and well-known phenomenon for low-energy fission of the lighter actinides, more recent experiments have demonstrated that, for the heaviest actinides, the mass distribution switches to a symmetric one. On the other hand, it has been discovered that, though for fissioning nuclei with mass numbers A< or [approx]225 the mass distribution is basically symmetric, an asymmetric component is clearly to be identified for nuclei down to the Pb-region. In the absence of a generally accepted dynamical theory of fission, the above experimental findings are discussed in terms of static energy considerations. Triggered from the outset by the structure of the potential energy surface at the saddlepoint, the energy ...

International Nuclear Information System (INIS)

A review of the experimental work performed at the GASP array with the purpose of the identification and first spectroscopic measurements of the heaviest even-even N = Z and odd-A N = Z + 1 nuclei (mass larger than 80) is made. Systematic experiments in this mass region led to the first study of seven such nuclei: "8"8Ru, "8"1Zr, "8"5Mo, "8"9Ru, "9"1Rh, "9"3Pd, and "9"5Ag, and extensive data on many other nuclei in their neighborhood. The systematic evolution of the level structures in both even-even and odd-A nuclei, between N #approx# Z #approx# 40 and N #approx# Z #approx# 47 is briefly presented. The possibility that effects of the neutron-proton pairing have been observed, as well as the type of collectivity observed in this region are discussed. (author)

CERN Document Server

The coherent $\\omega$-meson photoproduction from nuclei is proposed as a phenomenological method to evaluate the momentum dependence of $\\omega$-meson mass shift and width in nuclear matter. We analyze available data on un-separated coherent and incoherent $\\omega$-meson photoproduction from nuclei and extract the imaginary part of the the complex forward $\\omega{N}$ scattering amplitude, which is proportional to the in-medium $\\omega$-meson width. The accuracy of the currently available data is not sufficient to evaluate the real part of forward $\\omega{N}$ scattering amplitude and reconstruct the momentum dependence of the mass shift of the $\\omega$-meson.

Energy Technology Data Exchange (ETDEWEB)

A new two-body interaction recently derived for nuclei in the 0f1p shell by fitting two-body matrix elements to 494 energy levels in A=41-66 nuclei, is used to investigate the neutron-rich nuclei in the vicinity of the doubly closed nuclide {sup 48}Ca. This study is of fundamental interest in providing a test for the new effective interaction away from the stability line. Masses and binding energies are calculated for a variety of neutron-rich nuclei and compared with experimental data, where available. In addition level schemes for {sup 50-52}Ca, {sup 51-52}Sc and {sup 51-52}Ti have been calculated and are compared with available experimental data. In general a good correspondence between theory and experiment is found, but some systematic discrepancies are apparent. ((orig.)).

Energy Technology Data Exchange (ETDEWEB)

The masses of proton rich nuclides in the vicinity of N=Z=43 were measured with the Penning trap mass spectrometer SHIPTRAP at GSI. These nuclei were produced in the fusion-evaporation reaction {sup 36}Ar+{sup 54}Fe at energies of 5.0 and 5.9 MeV/u and separated at the velocity filter SHIP. The data are of astrophysical interest since these nuclei are believed to be a part of the rp and {nu}p process paths. The masses of {sup 85}Mo and {sup 87}Tc were measured for the first time. The masses of another two nuclides, {sup 86,87}Mo, were determined for the first time in a direct mass measurement. For these nuclides the mass excess deviates from values of the 2003 Atomic Mass Evaluation by up to 1.5 MeV, indicating a systematic shift of the mass surface in this region of the nuclear ...

Energy Technology Data Exchange (ETDEWEB)

Mass distributions of fragments in the low-energy fission of nuclei from {sup 187}Ir to {sup 213}At have been analysed. This analysis has shown that shell effects in symmetric-mode fragment mass yields from the fission of pre-actinide nuclei could be described if one assumes the existence of two strongly deformed neutron shells in the arising fragments with neutron numbers N{sub 1}{approx}52 and N{sub 2}{approx}68. A new method has been proposed for quantitatively describing the mass distributions of the symmetric fission mode for pre-actinides with A{approx}180-220. (orig.) 28 refs.

International Nuclear Information System (INIS)

The distributions of the effective numbers of 6q-fluctons in the energy, momentum and distance to the center of mass of nucleus are studied. Many characteristics of these distributions are shown to be universal, i.e. independent of the flucton size. The saturation of the flucton density in A > 80 nuclei and other peculiarities are found, which define different behavior of the effective numbers of fluctons and deuterons. This fact provides an explanation of the known underestimate by a factor of 1.5-6 of the cross sections of hard inclusive (p, p'd) process on nuclei calculated in the quasi-elastic approximation.

British Library Electronic Table of Contents (United Kingdom)

A study of elliptical flow is carried out for different mass asymmetries of colliding nuclei using the reactions of Formula Not Shown ( Formula Not Shown ), Formula Not Shown ( Formula Not Shown ) and Formula Not Shown ( Formula Not Shown ). The present reactions are simulated at incident energies between 50 and 250 MeV/nucleon within the framework of isospin-dependent quantum molecular dynamics model. For the present analysis, total mass of colliding pairs is kept fixed and mass asymmetry is varied between 0.3 and 0.7. The elliptical flow shows a transition from in-plane to out-of-plane in the mid rapidity region with incident energy. The transition energy is found to increase with the mass asymmetry for light charged particles. A good agreement is obtained with experimental measurements.

International Nuclear Information System (INIS)

A numerically feasible method, based on the use of deformed phonons, is developed for the diagonalization of the collective quadrupole Hamiltonian for a system with an odd particle coupled to an anharmonic even core. Examples: the transition from prolate to oblate via #gamma#-unstable shapes and furthermore the hsub(9/2) spectra of the nuclei "1"8"7Ir and "1"9"7Tl. (Auth.).

Energy Technology Data Exchange (ETDEWEB)

The contribution of pulsar accelerated nuclei to the cosmic rays inside the Galaxy is calculated assuming that a significant part of the pulsar rotational energy is lost on acceleration of iron nuclei extracted from the surface of the neutron star. Different models of the galactic pulsar population are discussed. It is shown that the best description of the observed cosmic ray spectrum and the mass composition between a few 10{sup 15} eV and a few 10{sup 18} eV is obtained for the model B of Lorimer et al. (1993)

Energy Technology Data Exchange (ETDEWEB)

Detailed level and decay schemes and the experimental reaction and decay data on which they are based are presented for nuclei with mass number A = 242; the experimental data are evaluated. Adopted values for level and ..gamma..-ray energies, ..gamma..-intensities, as well as other nuclear properties are given.

International Nuclear Information System (INIS)

Evaluated nuclear structure and decay data for all nuclei within the A = 203 mass chain are presented. This work supersedes the earlier evaluation by S. Rab (1993Ra11), published in Nuclear Data Sheets 70, 173 (1993).

International Nuclear Information System (INIS)

The analysis of elastic and inelastic scattering of #alpha# particles with energy of 50 MeV by nuclei with mass numbers A=54-124 and of "3He particles by the nucleus "6"4Ni is given in the framework of the optical model. The parameters of multipole deformations for lower states are determined. The parameters for quadrupole and octupole deformations of the potential for the nucleus "1"1"2Sn are extracted, the values of the hexadecupole deformation #beta#_4 of the potential for nuclei "9"4Zr, "1"2"0","1"2"4Sn are found. Information is extracted on the ratio of deformation parameters for the neutron and proton components in lower collective states (2_1"+, 3_1"-) of nuclei with A=90-124.

Energy Technology Data Exchange (ETDEWEB)

The energy, angular momentum, and distance (measured from the center of mass of the nucleus) distributions of the effective number of 6/ital q/-fluctons are investigated and it is shown that many of the characteristics of these distributions are universal, i.e., independent of the flucton size. ''Saturation'' of the flucton density in nuclei with mass /ital A//approx gt/80 and certain other features that determine the difference between the behaviors of the effective numbers of fluctons and deuterons are reported. This is used to explain the well known underestimation (by a factor of 1.5--6) of the cross section for the hard inclusive (/ital p/, /ital p/'/ital d/) process on nuclei calculated in the quasielastic formalism. See S. G. Kadmenskii and V. I. Furman, /ital Alpha/ /ital decay/ /ital and elated/ /ital nuclear/ /reactions/ (in Russian), ...

International Nuclear Information System (INIS)

The method of inversion of the eigenvalue problem previously developped for nuclei with axial symmetry is extended to asymmetric equilibrium shapes. This new approach to the asymmetric rotator model is applied to the odd-mass Iridium isotopes. A satisfactory and coherent description of the observed energy spectra is obtained, especially for the lighter isotopes. (orig.).

Energy Technology Data Exchange (ETDEWEB)

Evaluated nuclear structure and decay data for all nuclei within the A=177 mass chain are presented. Significant new information is included since the previous evaluation of this mass chain. The present work supersedes the earlier one by E. Browne (1993Br06), published in Nuclear Data Sheets 68, 747 (1993).

Energy Technology Data Exchange (ETDEWEB)

The ground state masses of thirty-nine neutron-rich nuclei from [sup 51]Ca to [sup 72]Ni have been measured using the Time-of-Flight Isochronous (TOFI) spectrometer. Eight of these masses have been measured for the first time and thirty-one are remeasurements of neutron-rich nuclei previously reported. Good agreement between these results and a previous TOFI experiment was observed except for the most neutron-rich isotopes of vanadium through iron with the present results being more bound and in better agreement with theory. The low binding energy of [sup 68]Ni, as indicated by an unreasonably low two-neutron separation energy, suggests the presence of a high-lying, long-lived isomeric state in this nucleus. (orig.)

Energy Technology Data Exchange (ETDEWEB)

The masses of the proton-rich nuclides {sup 85,86,87}Mo and {sup 87}Tc have been measured with the Penning trap mass spectrometer SHIPTRAP at GSI. The measured mass excesses of these nuclei deviate from the values of the Atomic Mass Evaluation 2003 by up to 1.6 MeV, indicating a systematic shift of the mass surface in this region compared to previous measurements. A local mass extrapolation based on the new results has been made for the mass range A=80-95. Measured and extrapolated mass values and the derived separation energies have been compared to theoretical mass models. Taking into account the new mass excess values, rp-process network calculations have been performed. Preliminary results show changes in the final abundances for A=86-92 by up to a factor ...

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared

International Nuclear Information System (INIS)

Study of the ground-state properties of Kr, Sr and Zr isotopes has been performed in the framework of the relativistic mean-field (RMF) theory using the recently proposed relativistic parameter set NL-SH. It is shown that the RMF theory provides an unified and excellent description of the binding energies, isotope shifts and deformation properties of nuclei over a large range of isospin in the Z=40 region. It is observed that the RMF theory with the force NL-SH is able to describe the anomalous kinks in isotope shifts in Kr and Sr nuclei, the problem which has hitherto remained unresolved. This is in contrast with the density-dependent Skyrme-Hartree-Fock approach which does not reproduce the behaviour of the isotope shifts about shell closure. On the Zr chain we predict that the isotope shifts exhibit a trend similar to that of the Kr and Sr nuclei. The RMF theory also predicts shape coexistence in heavy Sr isotopes. ...

Energy Technology Data Exchange (ETDEWEB)

Energy levels in N=50 nuclei are calculated allowing single-particle excitations from the p{sub 1/2} and g{sub 9/2} shells into the d{sub 5/2}, s{sub 1/2}, d{sub 3/2}, and g{sub 7/2} shells. Important parts of the interaction are determined by least-squares fits to known levels. Agreement with experiment is very good. The high-spin particle-hole states appear to be mainly yrast levels in mass 93 and higher, but are not in {sup 90}Zr. {copyright} {ital 1997} {ital The American Physical Society}

International Nuclear Information System (INIS)

Nuclear structure information for all nuclei with mass number A = 177 is summarized. Data from various decay and reaction experiments are compared. Evaluated data and the adopted spin, parity, and Nilsson--state assignments are given. Deviations from the regional trend of Nilsson ground-state assignments are noted for "1"7"7W and "1"7"7Re. Similar shifts have been observed in this region for nuclei 8 to 10 neutrons removed from the #beta#-stability line. In all cases, low-lying K/sup #pi#/ = 1/2/sup +-/ orbitals move to ground. Data received prior to February 1975 were included. (auth).

Energy Technology Data Exchange (ETDEWEB)

Neutron deficient nuclei with mass numbers A {approx} 90 and 40 {<=} Z {<=} 44 have been studied making use of the Osiris and Nordball spectrometers. The high spin states of these nuclei and their electromagnetic decay properties are compared to shell model calculations based on the core {sup 88}Sr and using different parametrizations of the residual interaction. The dependence of the mean square deviations of experimental and theoretical level energies, branching ratios, and transition probabilities on the neutron numbers N = 46-50 and the validity of seniority as a good quantum number are discussed. (orig.).

Science.gov (United States)

The masses of 16 neutron-rich nuclei in the mass range from 35 to 45 have been measured using a direct time of flight technique following the fragmentation of a {sup 48}Ca beam at 60 MeV/nucleon. The masses of {sup 35,36}Mg, {sup 38}Al, {sup 39,40}Si, {sup 42,43}P and {sup 43,44}S are reported for the first time. Preliminary analysis shows that the N=28 shell closure persists, even if weakened by the large neutron excess.

Energy Technology Data Exchange (ETDEWEB)

This work concerns the study of the nuclear superdeformation phenomenon in the rare earth region (A {approx} 150). The superdeformed (SD) states in Gadolinium and Dysprosium isotopes were produced via heavy-ion induced reactions and studied with the (EUROGAM EUROpean GAmma-ray Microscope) gamma multidetector array. Precise level attenuation method (DSAM). From the derived quadrupole moments, we find large differences in deformation between the yrast bands in neighbour nuclei explained in terms of the case of nuclei corresponding to an axis ratio of 2:1, the shell gaps are not fixed at a specific particle number and deformation. Furthermore the present results indicate that the deformations associated with identical bands are different supporting the picture that mass and deformation changes tend to compensate in SB bands with the same moments of inertia. (author). 114 refs.

Energy Technology Data Exchange (ETDEWEB)

Evaluated spectroscopic data for all nuclei with mass number A = 177 and corresponding level schemes from radioactive decay and reaction studies are presented. Most of the new information since the previous evaluation of this mass chain consists of the decay of the recently discovered isotope [sup 177]Tm, and the level structure of [sup 177]Ir, [sup 177]Os, and [sup 177]Pt. The present evaluation supersedes the earlier one by Y. A. Ellis and B. Harmatz (75E107) published in Nuclear Data Sheets 16, 135 (1975).

International Nuclear Information System (INIS)

Gamma-rays and conversion electrons emitted in the "1"1"7Cs and "1"1"7Xe decays have been studied from on-line mass-separated "1"1"7Cs sources at the ISOLDE facility. A new "1"1"7Xe decay scheme has been constructed and a level scheme has been established for the "1"1"7Cs decay. The results are discussed in the frame of our recent knowledge about odd-mass neutron-deficient I and Xe systematics.

International Nuclear Information System (INIS)

Detailed level schemes, decay schemes, and the experimental data on which they are based are presented for all nuclei with mass numbers A -- 216, 220, 224, and 228. The experimental data are evaluated; inconsistencies and discrepancies are noted; and adopted values for level and #gamma#-ray energies, #gamma# intensities, as well as for other nuclear properties are given.

Energy Technology Data Exchange (ETDEWEB)

Theoretical prediction of nuclear masses is analyzed as a pattern recognition problem on the N-Z plane. A global pattern is observed by plotting the differences between measured masses and Liquid Drop Model (LDM) predictions. After unfolding the data by removing the smooth LDM mass contributions, the remaining microscopic effects have proved difficult to model, although they display a striking pattern. These deviations carry information related to shell closures, nuc]ear deformation and the residual nuclear interactions. In the present work the more than 2000 known nuclear masses are studied as an array in the N-Z plane viewed through a mask, behind which the approximately 7000 unknown unstable nuclei that can exist between the proton and neutron drip lines are hidden. We show here that employing a Fourier transform deconvolution method these by masses can be ...

International Nuclear Information System (INIS)

... deformed nuclei eigenvalues even-odd nuclei gold 195 hamiltonians iridium

Energy Technology Data Exchange (ETDEWEB)

Nuclei in the mass-180 region have many high-{Omega} single-particle levels close to the Fermi energy and are, therefore, prime candidates for high-K isomers. Since both neutron and proton level densities are rather low, one should expect blocking and particle-number fluctuations to be rather important. We have performed good-particle-number calculations and have shown that the simpler blocked BCS theory gives a good approximation to the multi-quasiparticle spectra if the pairing strength is chosen appropriately. This has allowed us to perform a systematic theoretical study of this mass region. Residual spin-spin interactions are shown to be essential in reproducing the energies and even the correct order of known states. Good agreement has been found for {sup 175}Hf, {sup 176}Hf and {sup 177}Ta, where extensive data already exist. Predictions for new high-K states near the yrast line are made for these ...

International Nuclear Information System (INIS)

Progress in experimental investigations of high spin excitations in spherical and transitional nuclei in the A = 180 to 204 mass range is described. Most of the experiments were performed by in-beam #gamma#-ray spectroscopy using beams of "3He, "4He, and "1"2C ions from the Michigan State University cyclotron. The main results of studies of the nuclei "1"9"5 "1"9"7 "1"9"9 "2"0"1 "2"0"2 "2"0"3Pb, "1"9"6 "1"9"7 "1"9"9 "2"0"0Hg and "1"8"6 "1"8"7 "1"8"8 "1"8"9Pt are summarized.

Energy Technology Data Exchange (ETDEWEB)

A large area Bragg curve spectroscopy (BCS) detector and a position sensitive parallel grid avalanche counter have been developed to study heavy ion reactions, such as inelastic excitations and few nucleon transfer reactions near the Coulomb barrier. Reasonably good resolutions have been achieved for energy, atomic number and angle. A theoretical investigation on the mass dependence of the Bragg peak signal from the BCS detector, shows that there is a negligible mass dependence related to the geometry of the detector. The mass number of the heavy ions which cannot be obtained by the above method, has been identified by detecting the corresponding characteristic gamma rays from the product nuclei with two large solid angle gamma ray detectors. (orig.)

Energy Technology Data Exchange (ETDEWEB)

High-spin states in the neutron-rich nuclei {sup 172,173}Yb have been populated in a {sup 170}Er({sup 7}Li,(p,d,t)xn) incomplete-fusion reaction and the emitted {gamma}-radiation was detected with the GASP array. The signature partners of the 7/2{sup +}[633] rotational band of the odd-N {sup 173}Yb isotope have been newly established and were observed up to spin values of (45/2{sup +}) and (43/2{sup +}), respectively. The ground-state band of the even-even nucleus {sup 172}Yb has been observed up to a spin value of (22{sup +}). No band crossings were found in these bands. To explain this observation, it is proposed that the static pair field is absent, considering that the neutron odd-even mass differences reach for these nuclei very small values and that the band crossing is absent in cranked shell modell calculations without pairing. The results indicate, however, that strong dynamic correlations are still present. ...

International Nuclear Information System (INIS)

Becchetti's reply to the preceding ''Comment on "4H clustering in lithium nuclei''.

International Nuclear Information System (INIS)

The experimental study on #beta#-delayed proton decays near the proton drip line published by our group over the last 8 years were reviewed and summarized briefly, including first observation of 9 precursors in the rare-earth region and new measurements of 5 nuclei in the mass-90 region near N-Z line with the aid of the 'p-#gamma#' coincidence in combination with a He-jet tape transport system. Systematically comparing the experimental data with the current nuclear-model predictions, following points were represented. (1) the experimental half-lives for "8"5Mo and "9"2Rh as well as the predicted 'waiting point' nuclei "8"9Ru and "9"3Pd are 5-10 times longer than the macroscopic-microscopic model predictions given by Moeller et al. It considerably influences the prediction of mass abundances of the nuclides produced in rp-process. (2) The current-model predictions are not consistent with the experimental ...

International Nuclear Information System (INIS)

Nucleosynthesis and energy production in stellar environments depend critically on nuclear reaction cross sections. Reactions induced by alpha particles are important in the helium burning stage of stars, novae, and supernovae events. They involve light to medium weight nuclei up to about Z=32, and center-of-mass energies up to about 20 MeV. We are working on a project to compile and evaluate cross section data for alpha-induced reactions. These data will eventually be used to derive #alpha#-nucleus potential parameters. (author)

Energy Technology Data Exchange (ETDEWEB)

We have determined the nuclear charge radius of 11Li by high-precision laser spectroscopy. The experiment was performed at the TRIUMF-ISAC facility where the 7Li-11Li isotope shift was measured in the 2s to 3s electronic transition using Doppler-free two-photon spectroscopy with a relative accuracy better than 10 5. The accuracy reached in previous experiments on the other lithium isotopes was improved. Most of the isotope shifts measured in the experiment are due to difference in the mass of the nuclei but small contributions are produced by the change in proton distribution, QED and relativistic effects have to be taken into account as well. By comparing the experimental results with sophisticated atomic calculations of the mass dependent effect the nuclear charge radii of the lithium isotopes are found to decrease monotonically from 6Li to 9Li while the nuclear charge radius of 11Li is about 11% larger than that of 9Li.

Energy Technology Data Exchange (ETDEWEB)

This report describes progress made during the extended final year (April 1, 1992 to December 31, 1993) and summarizes the accomplishments of the entire three-year period (April 1, 1990 through December 31, 1993) of the current US Department of Energy grant DE-FG06-87ER40345. This work is carried out primarily at the UNISOR (University Isotope Separator at Oak Ridge) facility of the Holifield Heavy-Ion Research Facility of the Oak Ridge National Laboratory. The primary mission of this work is the study of the structure and properties of nuclei far from stability through on-line nuclear orientation using the UNISOR Nuclear Orientation Facility, a helium dilution refrigerator coupled on-line to the UNISOR mass separator. The author`s group was one of the original proposers of this facility and played a central role in its design, construction, and development. The structure of nuclei far from stability is in general poorly ...

International Nuclear Information System (INIS)

We briefly reviewed and summarized the experimental study on #beta#-delayed proton decays published by our group over the last 8 years, namely the experimental observation of #beta#-delayed proton decays of nine new nuclides in the rare-earth region near the proton drip line and five nuclides in the mass 90 region with N#approx#Z by utilizing the p-#gamma# coincidence technique in combination with a He-jet tape transport system. In addition, important technical details of the experiments were provided. The experimental results were compared to the theoretical predictions of some nuclear models, resulting in the following conclusions. (1) The experimental half-lives for "8"5Mo, "9"2Rh, as well as the predicted 'waiting point' nuclei "8"9Ru and "9"3Pd were 5-10 times longer than the macroscopic-microscopic model predictions of Moeller et al. [At. Data Nucl. Data Tables 66,131(1997)]. These data considerably influenced the predictions of the ...

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

International Nuclear Information System (INIS)

In the framework of spallation neutron sources and accelerator-driven systems, the international PISA (Proton-induced Spallation) collaboration has initiated measurements of total- and double-differential cross-sections for products of spallation reactions in a wide range of target nuclei (GU) at the COSY proton accelerator in Julich (Germany). The purpose is to study secondary particle production created in structural, window and target materials via proton beams up to 2.5 GeV of incident kinetic energy. Residual nuclei [H, He up to intermediate mass fragment (IMF)] production cross-sections are of great importance for estimating the damage to target and structure materials involving the planned spallation neutron sources, given that the lifetime of window and target materials is directly associated to those cross-sections. The demand for reliable theoretical predictions on production cross-sections is by no means ...

Energy Technology Data Exchange (ETDEWEB)

The aim of our research was to identify structures and chemical compositions of phases formed during internal oxidation of multi-component Ag-Zn-Mg-based alloys. Since the ability of inoculation mostly depends on large free energy of formation of oxides of microalloying elements and their crystallographic similarity, Mg in quantities of 0.001-0.5 mass% was selected as a micro-alloying element. These correspond to the quantities of 0.005-2.5 vol.% of MgO in the selected Ag-Zn-based alloys. Ag-based metal matrix, heterogeneous nuclei of MgO and oxide (ZnO) of the main alloying element were analysed by transmission electron microscopy (TEM). Structural inter-connections among them were also investigated and analysed. In situ phenomenon of heterogeneous nucleation of MgO and ZnO was proved. (orig.)

International Nuclear Information System (INIS)

Nuclear astrophysics seeks for a possible explanation of the observed abundance distribution of various elements and their isotopes in the universe. Most of the relevant nuclear reactions take place in thermally equilibrium environments with bare nuclei, rather than accelerated and head-on colliding situations with low ionisation states of reactant atoms and molecules that are emulated in the laboratories. Moreover, the temperature of the astrophysical environments is quite often low compared to the centre-of-mass energy of the projectile nuclides, that is required for the reaction to be meaningfully investigated in the laboratory. Therefore, an extrapolation of the data on the reaction cross sections to very low energies and to extremely high density situations is generally called for, which are substantially altered every now and then for a number of astrophysically important reactions. The radioactive ion beams will provide us important data ...

Energy Technology Data Exchange (ETDEWEB)

Thick-target recoil ranges of radioactive nuclei produced in 30-200 MeV alpha-particle bombardment of /sup 59/Co have been used to deduce the longitudinal momentum transfer per projectile nucleon (psub(parallel)/A) as a function of residue mass and bombarding energy. The average value of psub(parallel)/A increases monotonically with bombarding energy and reaches a maximum value of proportional160 MeV/c at proportional23 MeV/u, and decreases thereafter. The maximum value of psub(parallel)/A is equal to the incident momentum up to proportional23 MeV/u and saturates at a value of proportional220 MeV/c beyond this energy.

Energy Technology Data Exchange (ETDEWEB)

The mass and charge distributions in an unseparated mix of fission product nuclei from thermal-neutron fission of /sup 242m/Am were studied through semiconductor gamma-ray spectrometry. Samples of the fissionable material under study were irradiated in a vertical irradiation tube of the MIFI IRT research reactor. Following irradiation, measurements were made on aperture-calibrated semiconductor detectors. For broader identification of fission fragment nuclides three experiments were conducted that differed substantially in irradiation duration. The spectrum of gamma radiation from the mix of fission products and the time dependences of count rate at total absorption peaks were analyzed on SM-4 and Iskra-226 computers. The values of yields obtained were compared with data of investigations conducted earlier with other experimental methods, and also with the results of calculations.

Energy Technology Data Exchange (ETDEWEB)

The determination of ratio of neutron over proton matrix elements by inelastic proton scattering, for 0{sup +}{yields}2{sup +} transitions, is investigated via the comparison between experimental data and theoretical calculations. Calculations into the context of a macroscopic and a microscopic description are performed for a wide mass range nuclei: {sup 18}O, {sup 30}Si, {sup 32,34}S, {sup 48}Ca, {sup 88}Sr, for which these ratios were determined previously with an independent technique. At that point the choice of the theoretical model may be very critical. It is thus the purpose of this investigation to point out the most suitable model. It is found that in general both theoretical models can be employed for the reliable determination of neutron over proton matrix element ratios.

Energy Technology Data Exchange (ETDEWEB)

There has been considerable progress in developing SrBi{sub 2}Ta{sub 2}O{sub 9} (SBT) and Ba{sub O.7}Sr{sub O.3}TiO{sub 3} (BST) ferroelectric films for use as nonvolatile memory chips and for capacitors in dynamic random access memories (DRAMs). Ferroelectric materials have a very large dielectric constant ( {approx} 1000), approximately one hundred times greater than that of silicon dioxide. Devices made from these materials have been known to experience breakdown after a repeated voltage pulsing. It has been suggested that this is related to stoichiometric changes within the material. To accurately characterise these materials Elastic Recoil Detection Analysis (ERDA) is being developed. This technique employs a high energy heavy ion beam to eject nuclei from the target and uses a time of flight and energy dispersive (ToF-E) detector telescope to detect these nuclei. The recoil nuclei carry both energy and ...

CERN Document Server

We propose to investigate the in-medium properties of vector $\\omega$ mesons at the normal nuclear density in Ap(pA) collisions and at higher density in AA collisions at the ITEP accelerator facility TWAC. Using of the inverse Ap kinematics will permit us to study the $\\omega$ meson production in a wide momentum interval included the not yet explored range of small meson momenta relative to the projectile nuclei where the mass modification effect in nuclear matter is expected to be the strongest. Momentum dependence of the in-medium $\\omega$ meson width will be studied in the traditional pA kinematics. We intend to use the electromagnetic calorimeter for reconstruction of the $\\omega$ meson invariant mass by detecting photons from the $\\omega \\to \\pi^{0}\\gamma \\to 3\\gamma$ decay. The model calculations and simulations with RQMD generator show feasibility of the proposed experiment. Available now intensity of the ...

Energy Technology Data Exchange (ETDEWEB)

Relativistic mean field (RMF) theory is applied to modern problems of nuclear structure, such as the description of rotating bands in super-deformed nuclei or the investigation of neutron halos in light exotic nuclei. (orig.)

Energy Technology Data Exchange (ETDEWEB)

Q/sub ..beta..-values are determined for 18 nuclei (Zr-, Nb-, Mo-, Tc-, Ru- and Rh-nuclides) with mass numbers 101 less than or equal toA less than or equal to106 and A=109 from measurements of beta decay energies which were carried out at the LOHENGRIN mass separator at the Institut Laue-Langevin in Grenoble (France). The given Q/sub ..beta..-values between 2 and 8 MeV show errors of about 1.5% (with the exception of /sup 103/Zr and /sup 105/Nb resp. and /sup 103/Tc for which larger errors result due to statistical resp. systematic reasons): /sup 101/Zr 5500+-70, /sup 101/Nb 4580+-45, /sup 102/Zr 4670+-40, /sup 102/Nb 7230+-70, /sup 103/Zr 6790+-240, /sup 103/ 5740+-70, /sup 103/Mo 3575+-80, /sup 103/Tc 2585+-70, /sup 104/Nb 8250+-130, /sup 104/Mo 2180+-40, /sup 104/Tc 5520+-100, /sup 105/Nb 6570+-150, /sup 105/Mo 4885+-80, /sup 105/Tc 3750+-60, /sup 106/Mo 3515+-45, /sup 106/Tc 6540+-70, /sup 109/Ru 4150+-80, /sup 109/Rh ...

International Nuclear Information System (INIS)

... of Sciences (Poland) [5.48 Megabytes] NUCLEAR PHYSICS AND RADIATION

International Nuclear Information System (INIS)

Experimental data pertaining to nuclei with A=203 are compiled and evaluated.

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

Energy Technology Data Exchange (ETDEWEB)

This Report of activity displays the work developed at Centre d`Etude Nucleaires de Bordeaux-Gradignan (CENBG) in the period 1995-1996. A number of 68 short progress notes are presented in the fields of Cosmic particles (3), Nuclear Astrophysics (4), High Spins-Large Deformations (8), Basic Interactions (9), Exotic Nuclei (10), Hybrid Systems (4), Theoretical Physics (28), Cellular Microanalysis by means of Nuclear Probes (3) and Technical Development (3). The main problems attacked at CENBG, established as orientations by scientific board of IN2P3 (CENBG is a UMR of Bordeaux-1 Univ. and CNRS-IN2P3) are the following: the research of Majorana/Dirac nature of neutrino (in the framework of NEMO Experiment) in relation with the problem of origin of mass in the Universe and the cosmological puzzle of dark matter, the investigation of the origin of high energy (20 to 200 GeV) cosmic radiation (in the framework of CELESTE Experiment), the study of ...

International Nuclear Information System (INIS)

We investigate how 'extra' or 'excess' central light in the surface brightness profiles of cusp or power-law elliptical galaxies relates to the profiles of ellipticals with cores. The envelopes of cusp ellipticals are established by violent relaxation in mergers acting on stars present in gas-rich progenitor disks, while their centers are structured by the relics of dissipational, compact starbursts. Ellipticals with cores are formed by the subsequent merging of the now gas-poor cusp ellipticals, with the fossil starburst components combining to preserve a dense, compact component in these galaxies as well (although mixing of stars smooths the transition from the outer to inner components in the profiles). By comparing extensive hydrodynamical simulations to observed profiles spanning a broad mass range, we show how to observationally isolate and characterize the relic starburst component in core ellipticals. Our method recovers the younger starburst population, ...

CERN Document Server

Accretion processes in quasars and active galactic nuclei are still poorly understood, especially as far as the connection between observed spectral properties and physical parameters is concerned. Quasars show an additional degree of complexity compared to stars that is related to anisotropic emission/obscuration influencing the observed properties in most spectral ranges. This complicating factor has hampered efforts to define the equivalent of an Hertzsprung-Russel diagram for quasars. Even if it has recently become possible to estimate black hole mass and Eddington ratio for sources using optical and UV broad emission lines, the results are still plagued by large uncertainties. Nevertheless, robust trends are emerging from multivariate analysis of large spectral datasets of quasars. A firm observational basis is being laid out by accurate measurements of broad emission line properties especially when the source rest-frame is known. We ...

CERN Document Server

The antiproton-nuclei annihilation at the momentum range from 0.70 GeV/c to 2.50 GeV/c

International Nuclear Information System (INIS)

The angular #gamma##gamma#-correlations for nuclei of Sr even-even isotopes with a=8 82, 84, 86, 88 were measured. Multipole structurs of #gamma#-transtion series and th coefficients multipole mixing were determined.

International Nuclear Information System (INIS)

The new Gaussian potentials and interactions with forbidden states consistent with the phase scattering at low energies were obtained. Cross sections, resonance level spectra and some characteristics of bound states of lithium nuclei are calculated with these potentials.

UK PubMed Central (United Kingdom)

The number of nuclear pore complexes (NPCs) in individual nuclei of the yeast Saccharomyces cerevisiae was determined by computer-aided reconstruction of entire nuclei from electron...Full Text Available

International Nuclear Information System (INIS)

The EMS effect is explained in the flucton model as a consequence of scale invariance violation. Nontrivial behaviour of the ratio between structural functions and production cross sections for lepton pairs for different nuclei at x > 1 is predicted.

International Nuclear Information System (INIS)

... radioisotopes coincidence methods energy-level transitions gamma radiation

International Nuclear Information System (INIS)

... excited states iridium 187 isomeric nuclei magnetic fields nuclear electric

International Nuclear Information System (INIS)

... coupling deformed nuclei gold 195 high spin states iridium 187 moment of

CERN Document Server

PAMELA is a space telescope orbiting around the Earth since June 2006. The scientific objectives addressed by the mission are the measurement of the antiprotons and positrons spectra in cosmic rays, the hunt for anti-nuclei as well as the determination of light nuclei fluxes from Hydrogen to Oxygen in a wide energy range and with very high statistics. In this paper the charge discrimination capabilities of the PAMELA Time-Of-Flight system for light nuclei, determined during a beam test calibration, will be presented.

Energy Technology Data Exchange (ETDEWEB)

It is shown that a cosmic gamma-ray telescope made of a multilayer silicon tracker and a imaging CsI calorimeter, is capable of identifying cosmic ray nuclei. The telescope charge resolution is estimated around 4% independently of charge. Simulation methods are used to determine the telescope properties for nuclei detection.

International Nuclear Information System (INIS)

It is shown that the available experimental data on the x, Q"2, and A dependences of the structure functions of nuclei and their ratios (the EMC effect) can be described by the flucton model with rescaling of the parton distributions in nuclei. The x, Q"2, and A dependence of the nuclear structure functions in the cumulative region (x>1) is predicted.

International Nuclear Information System (INIS)

An approach to high energy nuclear reactions (relativistic nuclear physics) is developed on the basis of the quark-parton-flucton concept. The main assumptions underlying the known parton chain model are briefly reformulated, modified and generalized to the flucton case. This new model is used to investigate electron-nuclei and muon-nuclei inclusive reactions within the framework of quantum electrodynamics. The theoretical results are fitted well with existing data. (Auth.).

Energy Technology Data Exchange (ETDEWEB)

The fragment separator at GSI, Darmstadt, has been used to produce and separate very proton rich nuclei in the {sup 100}Sn region. By fragmentation of a {sup 112}Sn beam at 1 A{center_dot}GeV we produced nuclei along the rp-process path between {sup 77}Y and {sup 98}In. By implanting these ions into a silicon detector stack we were able to determine their halflives. Preliminary data are presented.

International Nuclear Information System (INIS)

Differences of the deformation parameters for the 2"+_1 states of even-even spherical nuclei extracted from electromagnetic excitation #beta#sup(em)_2 and from proton scattering #beta#sup(pp')_2 are discussed. It is found that the ratio #beta#sup(pp')_2/#beta#sup(em)_2 is equal to about unity and that there is a small isotope dependence for several incomplete shell nuclei. (orig.).

CERN Document Server

A Bragg curve ionization chamber for acceleration mass spectrometry

International Nuclear Information System (INIS)

A formalism for the dynamical treatment of the molecular orbitals of valence nucleons in nucleus-nucleus collisions is developed with the use of the coupled-reaction-channel (CRC) method. The Coriolis coupling effects as well as the finite mass effects of the nucleon are taken into account in this model, of rotating molecular orbitals, RMO. First, the validity of the concept is examined from the viewpoint of the multi-step processes in a standard CRC calculation for systems containing two identical [core] nuclei. The calculations show strong CRC effects particularly in the case where the mixing of different l-parity orbitals - called hybridization in atomic physics - occurs. Then, the RMO representation for active nucleons is applied to the same systems and compared to the CRC results. Its validity is investigated with respect to the radial motion (adiabaticity) and the rotation of the molecular axis (radial and rotational coupling). ...

International Nuclear Information System (INIS)

Neutron time-of flight spectra were measured from 90 MeV protons and 140 MeV alpha-particle bombardment of Al, Ni, Zr, and Bi at laboratory angles between 20"0 and 130"0. The proton induced neutron spectra reveal three distinct energy regions; a low energy evaporation region, a high-energy region dominated by quasi-free scattering processes and an intermediate-energy region dominated by multi-step, pre-equilibrium processes. In the latter two regions, the spectra show strong angular dependence. The alpha-induced neutron spectra show these same distinct energy regions plus an exponential fall-off above the beam energy per nucleon. The high-energy portions of the forward-angle neutron and proton cross sections are in ratios consistent with the assumption that single nucleon-nucleon scattering dominates. For heavy-mass targets, the low-energy evaporation regions show neutron yields larger than proton yields. The proton-to-neutron ratios observed in the high-energy ...

International Nuclear Information System (INIS)

Complete energy spectra and angular distributions of the light charged particles (A < or = 4) were measured for the bombardment of "2"7Al, "5"8Ni, "9"0Zr, "2"0"9Bi, and "2"3"2Th with 140 MeV #alpha# particles. The spectral shapes of a given emitted particle are very similar for all target nuclei except in the region of the evaporation peak. The slopes of the energy spectra in the forward direction become steeper as the mass of the observed particle decreases and vary very rapidly with angles. The experimental data can be characterized by compound nuclear evaporation processes at low energies, or at backward angles, and by direct reactions, nonequilibrium components and projectile breakup processes at high energies and forward angles. The breakup cross section for #alpha# particles is found to be appreciable. The total yield of light charged particles is approximately a factor approx. 2 to 3 larger than the total reaction cross section for ...

International Nuclear Information System (INIS)

The improved facilities of the ISOLDE isotopic separator on-line with the 600 MeV synchrocyclotron at CERN opened the possibility to reach nuclei very far from stability (as far as 22 neutrons deficient in the Cs region and 27 neutrons deficient in the Hg region). Simultaneously the development of on-line spectrometry allowed the study of nuclei with very short half-lives and low counting rates. Results recently obtained in the odd-A iridium region are presented after a short summary of recent on-line devices developments and results. (Auth.).

Energy Technology Data Exchange (ETDEWEB)

The process of inelastic scattering of hot plasma electrons with energies upto 3 keV by a pair of close-lying nuclear levels (..delta../ital E/less than or equal to2keV), one of whichis isomeric, is discussed. The transition cross sections in the nuclei/sup 242/Am, /sup 171/Lu, and /sup 73/Se are calculated. Estimates of the numberof isomeric nuclei de-excited as a result of electron-stimulated processes in aplasma with parameters characteristic of present-day experiments in controlledthermonuclear fusion are given.

Energy Technology Data Exchange (ETDEWEB)

The E1 and E3 transition operators in the sdf-IBA model are discussed. An effective E1 operator containing one- and two-body terms explains very well the E1 data in transitional and rotational nuclei. The E1 parameters for rotational nuclei are obtained by imposing a constraint on the IBA model namely, the validity of Alaga rules for ``pure K`` states. The systematic behavior of the octupole strength is well reproduced using a one-body octupole operator. The anomalously large fragmentation of the low-energy octupole strength in non-rotational nuclei is shown to be a signature of the O(6) dynamical symmetry.

International Nuclear Information System (INIS)

Properties of unique parity states in odd-proton (_7_7Ir, _7_9Au) and odd-neutron nuclei (_7_8Pt) are investigated in the framework of the interacting boson-fermion approximation model. The core (boson)-particle (fermion) interaction is represented by a quadrupole-quadrupole interaction and an exchange term, which takes into account the effects of the Pauli exclusion principle. The even-even core nucleus is described in terms of the IBA-1 hamiltonian. The change in the properties of the corresponding odd-A nuclei can be interpreted in terms of a transition of the core hamiltonian between the O(6) and SU(3) limiting cases. (orig.).

International Science & Technology Center (ISTC)

Experimental and Theoretical Study of the Residual Nuclide Production in 40-2600 MeV Proton-Irradiated Thin Targets of ADS Basic Materials

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

International Nuclear Information System (INIS)

Russian 1984. p. 353. USSR Smirnov, AV Antropov, AE Zarubin, PP

International Nuclear Information System (INIS)

(Jul 1974). Japan Kokame, J. Tokyo Univ., Tanashi (Japan). Inst. for

International Nuclear Information System (INIS)

Russian 1987. p. 99-100. USSR Sabalyauskas, L.Yu. Vanagas, VV Guseva,

Energy Technology Data Exchange (ETDEWEB)

Doubly decoupled structures in doubly odd deformed nuclei are reexamined and shown to be composed of a pseudo-spin aligned neutron and a decoupled proton. (orig.).

International Nuclear Information System (INIS)

Russian 1984. p. 351. USSR Burtebaev, NT Dujsebaev, AD Ivanov, GN

International Nuclear Information System (INIS)

(21 Jan 1974). Netherlands Lega, J. Macq, PC Louvain Univ. (Belgium)

Science.gov (United States)

creating such active galactic nuclei as quasars. Strangely, the center of this fiery whirlpool is offset from the exact center of the galaxy - for a reason that for now remains an...

International Nuclear Information System (INIS)

Russian 1979. p. 328. USSR Burtebaev, NT Dujsebaev, AD Ivanov, GN

Energy Technology Data Exchange (ETDEWEB)

It is carried out a calculation to determine the energy spectra of secondary {sup 3}He at small atmospheric depths. It is produced in the spallation reaction of primary helium and heavier nuclei in the overlying atmosphere. It is examined the effect of the geomagnetic cut-off on the spectral shape of the secondary {sup 3}He nuclei. The calculations are being carried out for both solar minimum and maximum periods. Results from these calculations will be presented at the Conference.

International Nuclear Information System (INIS)

... lutetium isotopes nuclei odd-even nuclei radioisotopes rhenium isotopes

Energy Technology Data Exchange (ETDEWEB)

The neutron deficient Sr and Zr nuclei are studied in the relativistic mean-field approach. Large deformations and shape coexistence are predicted for these nuclei in the vicinity of the proton drip line. The charge radii are found to increase with the removal of neutrons from the semimagic {sup 88}Sr and {sup 90}Zr, in close agreement with the recent isotopic-shift measurements.

Energy Technology Data Exchange (ETDEWEB)

The nucleon decay of subbarrier single-particle states with large angular momentum and parity opposite to that of the shell in soft spherical nuclei is considered. It is shown that the reduced probabilities of the nucleon decay into the ground state (0{sup +}) and into the first excited (2{sup +}) state of the daughter nucleus have qualitatively different energy dependences. (orig.).

International Nuclear Information System (INIS)

Nucleon decay of underbarrier one-quasiparticle states with large angular momentum in soft spherical nuclei is considered. It is shown that energy dependences of differential probabilities of nucleon decay to the ground (0"+) and first excited (2"+) states of daughter nucleus differ qualitatively from each other due to strong interaction between quasiparticles and low-lying quadrupole states.

International Nuclear Information System (INIS)

Based on a hypothesis of multiquark states in nuclei, the nucleus structure functions are considered and the results are compared with experiment. It is shown that the multiquark state contributions are sufficiently high (Up to 20% in deuterium and 40% in iron) and must possess a greater, than in a nucleon, sea of quark-antiquark pairs. Also the comparison with the cumulative particle production cross sections is performed. The predictions are given for a further experimental test of that hypothesis.

Energy Technology Data Exchange (ETDEWEB)

Given the spectrum of a Hamiltonian, a methodology is developed which employs the Landau-Ginsburg theory for characterizing phase transitions in infinite systems to identify phase transition remnants in finite fermion systems. As a first application of our approach we discuss pairing in finite nuclei. (orig.)

CERN Document Server

The Baldwin Effect, a negative correlation between emission-line equivalent width and luminosity in active galactic nuclei, is still of interest as a diagnostic of accretion physics nearly thirty years after its discovery. This review examines recent developments in the study of correlations between line and continuum emission in AGNs, as measured both in ensembles and in individual sources.

International Nuclear Information System (INIS)

Cross sections for elastic scattering of 12 GeV protons from "4"0Ca nuclei have been calculated using the flucton model. The influence of the collective flucton nucleon correlations on the calculated cross sections is examined. The calculated cross sections are in significant disagreement with the experimental data. This may be considered as an argument against the flucton model. (orig.).

International Nuclear Information System (INIS)

We calculate parity-dependent level densities for the even-even isotopes "5"8","6"2","6"6Fe and "5"8Ni and the odd-A nuclei "5"9Ni and "6"5Fe using the shell model Monte Carlo method. We perform these calculations in the complete fp-gds shell-model space using a pairing+quadrupole residual interaction. We find that, due to pairing of identical nucleons, the low-energy spectrum is dominated by positive parity states. Although these pairs break at around the same excitation energy in all nuclei, the energy dependence of the ratio of negative-to-positive parity level densities depends strongly on the particular nucleus of interest. We find equilibration of both parities at noticeably lower excitation energies for the odd-A nuclei "5"9Ni and "6"5Fe than for the neighboring even-even nuclei "5"8Ni and "6"6Fe.

Science.gov (United States)

No Abstract Available

International Nuclear Information System (INIS)

Full text: Lung cancer is responsible for most of the cancer related deaths and calls for new approaches to control the menace. In the present study chemopreventive efficacy of curcumin and quercetin was investigated against benzo(a)pyrene (BP) induced lung carcinogenesis. The mice were segregated into five groups which included normal control, BP treated, BP+curcumin treated, BP+quercetin treated and BP+curcumin+quercetin treated groups. The morphological and histological analyses of tumor nodules confirmed lung carcinogenesis, after 22 weeks of single i.p. injection of BP at a dose of 100 mg/Kg body weight to mice. Tumor incidence and tumor multiplicity were observed to be 88% and 1.75, respectively in the BP treated mice. A statistically significant increase in the uptake of "3H thymidine indicative of increased DNA synthesis which in turn is the marker of uncontrolled cancer cell proliferation, was observed in the lung slices of BP treated mice. Further, BP treatment resulted in ...

International Nuclear Information System (INIS)

Nuclear battery produces electricity by converting radiation energy into electrical energy. Energy carried by particles emitted by a radioisotope nuclei is much higher than that released in chemical reaction. Reaction with nuclei can potentially produce electricity thousand to million times higher than that of chemical reaction. Unlike NPP that produces large scale alternating current using thermodynamic cycle such as Rankine or Brayton cycles, nuclear battery is designed like other battery or fuel cell, to produce direct current (DC). However, both battery utilize the energy or particles radiating from nuclei of a radioisotope. In this paper, several types of nuclear battery as an energy converter are discussed, including their working mechanisms and examples. Nuclear battery is potential to become a long-life power source for use in wide range of applications, including in medical areas and for instruments in remote areas ...

International Nuclear Information System (INIS)

Hyperspherical-harmonics method to investigate the lightest nuclei having three-cluster structure is discussed together with recent experiments. Properties of bound states and methods to explore three-body continuum are presented. The challenges created by large neutron excess and halo phenomena are highlighted. Astrophysical aspects of the "7Li + n "#-># "8Li + #gamma# reaction and the solar-boron-neutrinos problem are analyzed. Three-cluster structure of highly excited states in "8Be is shown to be responsible for extreme isospin mixing. Progress in studies of "6He- and "1"1Li-induced inclusive and exclusive nuclear reactions is demonstrated, providing information on the nature of continuum structures of Borromean nuclei.

Energy Technology Data Exchange (ETDEWEB)

The description of the high energy particle telescope NINA for the study of cosmic ray nuclei is presented. The instrument will be installed on board of the Resource 01 satellite and will fly on a polar orbit at 690 Km. The telescope consists on a pile of 16 detecting planes each of them is composed by two silicon strip detectors with perpendicular strips and has a total area of 60x60mm{sup 2}. The experiment goals are the study of cosmic ray protons and nuclei in the energy range 12-100 MeV/amu. It will be sensitive to the anomalous component and will also make the observation of the large solar flare events and geophysical phenomena as well. This experiment is the first step of the program RIM whose goal is the satellite study of anti particles in primary cosmic rays.

International Nuclear Information System (INIS)

Short note. 4 refs.; 1 tab.

International Nuclear Information System (INIS)

several authors tried to drive codes to construct nuclear level scheme of nuclei using a set of measured gamma -ray transitions and known energy levels, Ritz combination principle proved to be useful in constructing a more complete decay scheme. In this thesis the energy level schemes of some nuclei have been investigated by the measurements of the gamma - ray energies and use of Ritz combination code. The nuclei under investigation are "110m Ag (253 d)"110 Cd and "166m Ho (1200 yr) "166 E r. On the basis of the suggested level at 2249.02 keV by the Ritz code new positions of the two gamma-ray transitions at 677.5 and 706.6 KeV are found in decay scheme of "110m Ag. Also by this code, new position for the 994.84 KeV gamma-ray transition were established to depopulate the level at 1075.2 KeV.

International Nuclear Information System (INIS)

Starting with a #LAMBDA#-nucleus potential, a semi-empirical formula, which gives a fairly satisfactory account of the ground state #LAMBDA#-binding energy of light hypernuclei, if the very light nuclei are ignored has been obtained. (author).

UK PubMed Central (United Kingdom)

The standard nomenclature that has been used for many telencephalic and related brainstem structures in birds is based on flawed assumptions of homology to mammals. In particular, the outdated...Full Text Available

UK PubMed Central (United Kingdom)

We describe the characteristics of the rapidly rotating molecular disk in the nucleus of the mildly active galaxy NGC4258. The morphology and kinematics of the disk are delineated by the point-like...Full Text Available

International Nuclear Information System (INIS)

Russian 1984. p. 349. USSR Burtebaev, NT Dujsebaev, AD Knyaz'kov, OM

Energy Technology Data Exchange (ETDEWEB)

We summarize some initial results in our investigation of the nuclear physics issues of gamma-ray lasers. We describe what is known thus far from existing experimental data and illustrate how theoretical models may be employed for systematic searches of candidate nuclei.

Energy Technology Data Exchange (ETDEWEB)

The Schroedinger equation for nuclear quadruple surface vibrations is linearized with the consequence that a new spin degree of freedom appears in the wave function of the linearized equation. This spin is called collective spin and has a value of 3/2. The linearized Schroedinger equation for quadrupole vibrations is used for the description of certain collective aspects of even-odd {sup 187,189,191}Ir nuclei which have a spin 3/2 in their ground state. As a potential we use the {gamma}-soft collective potential of the neighboring even-even nuclei, which is inserted into the linearized Schroedinger equation via a scalar coupling. This leads to a collective spin-dependent fine structure splitting of the energy levels governed by a collective SO(5) spin-orbit coupling and a correction to the kinetic energy. Further, we consider explicitly spin-dependent potentials which effectively describe the interaction of the valence nucleon with the core of ...

International Nuclear Information System (INIS)

Theoretical interpretation of fast-charged-particle spectra, observed in the #alpha#-particle-induced reactions on the s-d shell nuclei (A = 24-28), in terms of the Intranuclear Cascade Model and the GDH exciton model (ALICE) is presented. The de-excitation of the excited residual nuclei is accounted for by the evaporation process. The theoretically predicted fast-proton and #alpha#' spectral shapes compare reasonably well with the corresponding measured spectra. However, the magnitude depends critically (as expected) on the reaction cross section employed by the model. As a first step to improve the model predictability of the reaction products, a closer look at the calculation of the #alpha#-particle reaction cross sections was undertaken. A microscopic approach using the optical theorem of Glauber's theory was employed to estimate the #alpha#-induced reaction cross sections for the light target nuclei under ...

International Nuclear Information System (INIS)

Russian 1986. p. 334. USSR Burtebaev, NT Dujsebaev, AD Sadkovskij,

Energy Technology Data Exchange (ETDEWEB)

An application of the renormalized random phase approximation to nuclear structure is presented for the semi-magic nuclei /sup 88/Sr and /sup 90/Zr. It is reported the outcome for the microscopic approach in comparison with the semiphenomenological version for the particle-hole forces.

UK PubMed Central (United Kingdom)

Bacteria and fungi are ubiquitous in the atmosphere. The diversity and abundance of airborne microbes may be strongly influenced by atmospheric conditions or even influence atmospheric conditions themselves...Full Text Available

International Nuclear Information System (INIS)

Russian 1977. p. 178. USSR Feofilov, GA Denisov, AE Kolalis, RP Sadkovskij,

International Nuclear Information System (INIS)

Ammonia adsorption on the external surface of C_3_0B_1_5N_1_5 heterofullerene was studied using density functional calculations. Three models of the ammonia-attached C_3_0B_1_5N_1_5 together with the perfect model were optimized at the B3LYP/6-31G"* level. The optimization process reveals that dramatic influences occurred for the geometrical structure of C_3_0B_1_5N_1_5 after ammonia adsorption; the B atom relaxes outwardly and consequently the heterofullerene distorts from the spherical form in the adsorption sites. The chemical shielding (CS) tensors and nuclear quadrupole coupling constants of B and N nuclei were calculated at the B3LYP/6-311G"*"* level. Our calculations reveal that the B atom is chemically bonded to NH_3 molecule. The B atom in the NH_3-attached form has the largest chemical shielding isotropic (CSI) value among the other boron nuclei. The C_Q parameters of B nuclei at the interaction sites are ...

International Nuclear Information System (INIS)

Results are presented of an empirical analysis of the global thermodynamical requirements of the winds in the outer atmospheres of a representative sample of red giant stars of low- and intermediate-mass range. Results indicate that the mass-loss rates in these stars are not strongly dependent on the actual physical processes driving the winds. It is suggested that nonlinear processes act to regulate wind energy fluxes. Possible mechanisms responsible for the chromospheric heating and the mass loss in the low- and intermediate-mass giant stars are discussed. 151 refs.

Energy Technology Data Exchange (ETDEWEB)

The statistical {gamma}-spectra of highly excited even-even rare earth nuclei are simulated applying appropriate level density and strength function to a given nucleus. Hindrance effects due to K-conservation are taken into account. Simulations are compared to experimental data from the {sup 163}Dy({sup 3}He,{alpha}){sup 162}Dy and {sup 173}Yb({sup 3}He,{alpha}){sup 172}Yb reactions. The influence of the K quantum number at higher energies is discussed. 21 refs., 7 figs., 2 tabs.

International Nuclear Information System (INIS)

The average single-particle field shows a very small pseudo-spin-orbit splitting in the pseudo-spin representation. If this splitting is neglected, pseudo-spin becomes a good quantum number and the resulting scheme (the pseudo-Nilsson model) has a very simple interpretation. The pseudo-spin symmetry embodied in the realistic deformed average field is explored by comparing the single-particle energies and wave functions of the deformed Woods-Saxon model with the corresponding results of the pseudo-Nilsson model. The scheme is used to calculate the magnetic moments of deformed odd-A nuclei of the rare-earth region. (orig.).

International Nuclear Information System (INIS)

A ''coherent flucton'' nuclear model is proposed which provides for new possibilities for particle scattering studies on nuclei. It is based on the data of nuclear matter density distribution and is used for calculating the ground state energy of Fermi system terminals. The ''coherent flucton'' model is applied to the distribution of 1 GeV protons on "2"8Si, "3"2S, "4"0Ca, "4"8Ca, "5"8Ni, "2"0"8Pb nuclei. The calculations by the model agree well with experimental data.

Energy Technology Data Exchange (ETDEWEB)

The nuclei {sup 81}Zr and {sup 85}Mo with T{sub z}=1/2 have been reinvestigated via their {beta}-delayed proton emissions with p-{gamma} coincidence measurement. The half-life of {sup 81}Zr has been measured to be 5.3{+-}0.5 s, which agrees with one of the two previous values. For {sup 85}Mo, the measured half-life is 3.2{+-}0.2 s, which revises the previous value. (orig.) With 3 figs., 12 refs.

Energy Technology Data Exchange (ETDEWEB)

A technique for calculation of the total weight of quark clusters-fluctons: in nuclei is developed. Blokhintsev's formula is justified microscopically and refined by introduction of spin-charge and quark factors. It is shown that the large values of the correlation radius (R/sub C/approx. =0.75 fm or 1.0 fm) derived from experimental data in various papers using this formula correspond to )similarreverse arrowto)2.5 times smaller internucleon distances in the flucton (0.3--0.4 fm), i.e., the hardness of fluctons is caused by unsuppressed manifestation of hidden color at such distances (the corresponding probabilities are presented)

International Nuclear Information System (INIS)

"2H, "4He, "1"6O, "4"0Ca, "8"0Zr, "1"4"0Yb, "2"2"4112, "3"3"6168 nuclei are invesigated in terms of flucton model. Effective numbers of nuclear fluctons and deuterons are calculated. Values of complete effective numbers of low-radius deuterons and fluctons with S=1 spin and T=0 isospin are presented. Investigation results of inclusive reactions of quasi-elastic knock-out of deuterons by fast protons are discussed. 9 refs.; 1 fig.; 1 tab.

Energy Technology Data Exchange (ETDEWEB)

The available experimental data on the (/sup 3/He,n) reaction between the ground states of even-even nuclei and lowest 1/2/sup -/ levels of odd-A nuclei in the Aapprox.=100 region are analyzed in a systematic way by the DWBA. The deduced relative intensities of these two-proton transfers, and their uncertainties, are compared to the predictions of various nuclear models. In particular, the influence of the finite dimension of the configuration space available to the transferred protons, and of the blocking effect of a 2p1/2/sup -/ proton, are examined. (orig.).

Energy Technology Data Exchange (ETDEWEB)

A theoretical derivation of the intershell mass--core mass relation of Paczynski is attempted. Formulae developed by Sugimoto and Fujimoto are extended to less massive (m/sub c/< or approx. =1) cores.

UK PubMed Central (United Kingdom)

The obligations of organisations associated with policy formation and implementation of international mass public health programmes are explored. Lines of responsibility are considered to become unclear...Full Text Available

CERN Document Server

We discuss first the flavor mixing of the quarks, using the texture zero mass matrices. Then we study a similar model for the mass matrices of the leptons. We are able to relate the mass eigenvalues of the charged leptons and of the neutrinos to the mixing angles and can predict the masses of the neutrinos. We find a normal hierarchy - the masses are 0.004 eV, 0.01 eV and 0.05 eV. The atmospheric mixing angle is given by the mass ratios of the charged leptons and the neutrinos. we find about 40 degrees, consistent with the experiments. The mixing element, connecting the first neutrino wit the electron, is predicted to be 0.05. This prediction can soon be checked by the Daya Bay experiment.

Energy Technology Data Exchange (ETDEWEB)

Fusion energy is one of only a few truly long-term energy options. Since its inception in the 1950s, the vision of the fusion energy research program has been to develop a viable means of harnessing the virtually unlimited energy stored in the nuclei of light atoms--the primary fuel deuterium is present as one part in 6,500 of all hydrogen. This vision grew out of the recognition that the immense power radiated by the sun is fueled by nuclear fusion in its hot core. Such high temperatures are a prerequisite for driving significant fusion reactions. The fascinating fourth state of matter at high temperatures is known as plasma. It is only in this fourth state of matter that the nuclei of two light atoms can fuse, releasing the excess energy that was needed to separately bind each of the original two nuclei. Because the nuclei of atoms carry a net positive electric charge, they repel each other. ...

International Nuclear Information System (INIS)

Modern nuclear spectroscopy boosts the study of the nuclear matter towards extreme conditions: large excitation energies, high spins, and new nuclear species with unusual ratio between the numbers of neutrons and protons. One of the 'exotic' nuclear regions, practically not studied until now, is the upper part of the N=Z line, from about N#approx#Z#approx#36 to Sn-100, probably the heaviest bound nucleus with N=Z. These nuclei lie close to the proton-drip line. Due to their special composition, it is expected that their study will reveal some phenomena which are less encountered in the nuclei studied till now. In particular, of outstanding interest is the fact that these are the only nuclei which may provide information on the properties of the neutron-proton pairing forces. In spite of its large interest, this nuclear region is exceedingly difficult to reach with the present techniques. The lecture follows the latest ...

Science.gov (United States)

Not Available

Energy Technology Data Exchange (ETDEWEB)

The mass-energy spectra of the fragments of thermal fission of {sup 242m}Am are measured using the time-of-flight technique. The resulting mass-yield curve and peak-to-valley ratio agree with radiochemical data. The parameters of the kinetic energy distribution of the fragments are determined for the first time. Data on the fine structure of mass spectra in the region of cold fragmentation are presented. 15 refs., 4 figs.

KoreaScience (Korea)

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CERN Document Server

We investigate the influence of the turbulence forcing on the mass distributions of gravitationally unstable cores by postprocessing data from simulations of non-selfgravitating isothermal supersonic turbulence with varying resolution. In one set of simulations solenoidal forcing is applied, while the second set uses purely compressive forcing to excite turbulent motions. From the resulting density field, we compute the mass distribution of gravitationally unstable cores by means of a clump-finding algorithm. Using the time-averaged probability density functions of the mass density, semi-analytic mass distributions are calculated from analytical theories. We apply stability criteria that are based on the Bonnor-Ebert mass resulting from the thermal pressure and from the sum of thermal and turbulent pressure. Although there are uncertainties in the application of the clump-finding ...

Energy Technology Data Exchange (ETDEWEB)

The thesis deals with measurement of the mass of the W boson at LEP2, based on the direct reconstruction of its decay products in the hadronic channel. A set of procedures necessary for the extraction of the W mass from the experimental data collected with the DELPHI detector in 1997 was developed (search of optimal variables for the event selection, development of a special method of kinematical reconstruction). The measured value of the mass was interpreted in the framework of the Standard Model, allowing to constrain the mass of the Higgs boson. A substantial part of the work is devoted to systematic effects due to the interactions between the hadronic decay products of the W bosons (colour reconnection and Bose-Einstein correlations), which may significantly influence the measurement of their mass. (author) 53 refs., 104 figs., 33 tabs.

Science.gov (United States)

Least-squares analyses were performed on a set of atomic masses using standard and generalized senaiempirical mass laws. Presumably because of errors in the assured form of the standand mass law, its least-squares coefficients can be determined at best to an accuracy of about 10%, and masses are predicted with an uncertainty of several Mev/c/sup 2/. The standard mass law was generalized by addition of shell effect and deformation terms. While the least-squares fitting of the generalized mass law is better than for the standard mass law, it is still not possible to predict atomic masses to an accuracy better than a few Mev/c/sup 2/. The nuclear deformations and the well depth . of the nuclear interaction obtained from the additional mass-law terms are in reasonable agreement ...

British Library Electronic Table of Contents (United Kingdom)

A metamaterial that is composed of solid viscoelastic elements with controllable properties is proposed in this Letter. This enables an adaptable and general acoustic metamaterial to be practically realised. An array of masses with a single elastic connection to a supporting viscoelastic structure, such as one that is dynamically equivalent to an array of Helmholtz resonators, only provides a system with negative effective mass. A local active control scheme applied to each of these masses can emulate additional elastic connections to the supporting structure. An array of masses with a suitable local control scheme can provide both the negative effective stiffness and mass required for negative refraction. The tuneable feedback control parameters determine the characteristics of the region...

International Nuclear Information System (INIS)

Nucleon and meson effective masses in the nonlinear relativistic mean-field theory introducing a nonlinear #omega#-#rho# and #sigma# coupling motivated by the quark-meson coupling model is explored. It is shown that, in contrast to the usual Walecka model, not only the effective nucleon mass m_e_f_f_,_N but also the effective #sigma#,#rho# meson masses (m_e_f_f_#sigma#,m_e_f_f_,_#rho#) and the effective #omega# meson mass m_e_f_f_,_#omega# are nucleon density dependent. (author)

International Nuclear Information System (INIS)

The mass of the nucleon is studied in a chiral quark-diquark model. Both scalar and axial-vector diquarks are taken into account for the construction of the nucleon state. After the hadronization procedure is used to obtain an effective meson-baryon Lagrangian, the quark-diquark self-energy is calculated to generate the baryon kinetic term as well as determine the mass of the nucleon. It turns out that both the scalar and axial-vector parts of the self-energy are attractive for the mass of the nucleon. We investigate the range of parameters that can reproduce the mass of the nucleon.

Energy Technology Data Exchange (ETDEWEB)

Mass distribution in 28.5 MeV alpha particle induced fission of {sup 232}Th has been determined using gamma spectrometric technique. The chain yields of 24 different fission products covering both symmetric and asymmetric mass divisions were determined. The mass distribution was found to be asymmetric with peak positions at mass numbers 96 and 136 respectively while the peak to valley ratio was 3.86. The results are compared with the available literature on 14 MeV neutron induced fission of {sup 235}U. (orig.).

British Library Electronic Table of Contents (United Kingdom)

The acoustic hyperlens can be realized by an alternating layered structure of water and fluid with negative mass density. Based on this alternating layered principle, we propose that an acoustic metamaterial consisting of three layers in water background can be designed to replace the fluid with negative mass density. The effective mass density and bulk modulus of the system which is composed of acoustic metamaterial and water are functions of the frequency. The effective mass density of such a system is close to the negative mass density of the fluid at a specific frequency; thus an acoustic metamaterial hyperlens can be achieved.

International Nuclear Information System (INIS)

We studied the magnetic dipole moments #mu# of even-odd C isotopes, ranging from proton-rich to neutron-rich nuclei, with antisymmetrized molecular dynamics (AMD). The results are in good agreement with the experimental data. In the "9C ground state the total intrinsic spin of the protons is found to be nonzero (S_p#not =#0), which is unusual in even-odd nuclei. The interesting point is that the spin-orbit force breaks slightly the coupling off of intrinsic spins of the even nucleon group in isospin T=3/2 nuclei. This result is consistent with the newly measured #mu# data that, when combined with "9Li data, indicate an unusual left-angle #sigma# right-angle value larger than unity. A #mu# moment -1.05#mu#_N of "1"7C is theoretically predicted. We also show a good reproduction of E2 transition data. copyright 1996 The American Physical Society.

Energy Technology Data Exchange (ETDEWEB)

Accurate calculations of atomic displacement damage in materials exposed to neutrons require detailed spectra for primary recoil nuclei. Such data are not available from direct experimental measurements. Moreover, they cannot always be computed accurately starting from evaluated nuclear data libraries such as ENDF/B-V that were developed primarily for neutron transport applications, because these libraries lack detailed energy-and-angle distributions for outgoing charged particles. Fortunately, a new generation of nuclear model codes is now available that can be used to fill in the missing spectra. One example is the preequilibrium statistical-model code GNASH. For heating and damage applications, a supplementary code called RECOIL has been developed. RECOIL uses detailed reaction data from GNASH, together with angular distributions based on Kalbach-Mann systematics to compute the energy and angle distributions of recoil nuclei. The ...

International Nuclear Information System (INIS)

An analysis of the total photoabsorption cross section for nuclei ranging from "4He up to "2"3"8U has been performed in the energy range 0.2-1.0 GeV. Mean total photoabsorption cross sections have been obtained by summing up the contributions from partial photoreactions, and found to follow an A"1-dependence in the 0.2-1.0 GeV range. A review of the available total photoabsorption cross section data is also presented. Comparisons have been made with cross section values calculated by considering both the quasi-deuteron and #pi#-meson photoproduction mechanism of primary nuclear photointeraction. (orig.).

International Nuclear Information System (INIS)

The linearized collective Schroedinger equation for nuclear quadrupole surface vibrations incorporates a new spin degree of freeedom with a spin value of 3/2. We use this equation to describe the low energy spectrum of certain even-odd Ir nuclei which have a spin 3/2 in their ground state. For that purpose we explicitly introduce collective spin-dependent potentials which simulate the interaction of the valence nucleon with the core. The linearized Schroedinger equation is transformed into an effective Schroedinger equation with collective spin-dependent potentials. Already collective spin-orbit couplings of SO(3) and SO(5) type are sufficient to reproduce the lowest excited states of even-odd Ir nuclei. (orig.).

International Nuclear Information System (INIS)

We report here results of an application of single-nucleon stripping reactions at high energies (65 MeV/u) in inverse kinematics to obtain spectroscopic factors. From measurements of the partial cross-sections for ground and excited states in residual nuclei formed in one-proton stripping reactions, single particle orbits and occupancies of light nuclei have been studied in the s-d shell. Single proton stripping cross-sections of "2"5Al and "2"6","2"7","2"8P on a Be target have been measured using the S800 spectrograph and the NaI(Tl) array at the NSCL. These results indicate that this technique may provide a general tool for the intermediate energy range analogous to transfer (pick-up) reactions at low-energy.

British Library Electronic Table of Contents (United Kingdom)

Reduced systems such as brain slices offer a powerful approach to study the physiology of auditory neurons in great detail. However, when studying auditory nuclei in reduced systems such as brain slices, especially highly active auditory brain stem nuclei, one has to be aware that the unphysiological lack of activity in the reduced system compared to the in-vivo situation has a number of important effects on the neurons under investigation, and thus on the data that are measured. Most importantly, the lack of chronic activity in the slice preparation has important effects on the properties of short-term plasticity of the synapses. The main purpose of this article is to discuss how spontaneous activity in auditory neurons, or the lack thereof, can affect the data measured.

International Nuclear Information System (INIS)

Differential cross sections for the excitation of the first octupole-vibrational state in the closed-neutron-shell nuclides "8"8Sr and "9"0Zr and in the closed-proton shell-nuclei sup(116,118,120,124)Sn by 11 MeV neutrons are presented. The distorted-wave Born approximation is used to obtain deformation lengths, delta(3"-) for each state. Results are compared with earlier measurements of inelastic proton scattering to the same states. Although limited resolution in the neutron time-of-flight spectrometer complicates the interpretation of the Sn data, the overall conclusion that deltasub(nn')(3"-) approx. deltasub(pp')(3"-) is supported by all of the measurements. (orig.).

CERN Document Server

We present evidence in favour of a link between the luminosity radiatively dissipated in the central engine of radio-loud Active Galactic Nuclei and the kinetic power in their jets. This piece of evidence is based on the relation we find between the luminosity in broad emission lines and the kinetic power in pc-scale radio jets, for a sample of radio-loud quasars for which suitable data are available in the literature. We find that the ionizing luminosity and the kinetic one are of the same order of magnitude, suggesting that the processes responsible for them are somehow related. A strong magnetic field in equipartition with the radiation field could be responsible for regulating both processes. BL Lac objects seem to follow a similar behaviour, but with comparatively fainter broad line emission.

Science.gov (United States)

It is shown that level-density expressions cannot adequately represent or substitute for level structure information when making calculations of the Hauser-Feshbach type for cross sections or isomer-ratios for nuclei in the first few MeV above their ground state. It is stated that such discrete level information should include both experimentally confirmed and theoretically predicted levels. The utility of discrete level information to optimize level density calculations, to compute isomer ratios, in deriving dipole strength functions, and in the analysis of primary gamma ray spectra is emphasized, especially for nuclei far from the line of stability. 29 refs., 12 figs., 6 tabs. (DWL)

International Nuclear Information System (INIS)

Pearls change their color to grey by #gamma#-ray irradiation. Grey densities were determined from darkness of pearl nuclei and thickness of the pearl layers. The densities are independent of both diameters of nuclei and pearls. The fading rate increases with increasing storage temperature. The rate of fading for irradiated pearls is lower than that for natural blue pearls. Comparison of photomicrographs (x 12) for pearls irradiated and then stored at room temperature for about 6 years revealed that their surfaces are not substantially different from the surfaces of unirradiated cultured pearls, indicating that #gamma# irradiation hardly gives rise to deterioration. #gamma#-Ray irradiation is a technique for coloration of pearls. Irradiated blue pearls seem to have resistivity to fading and to deterioration of the surface, if pearls have been irradiated properly. (author).

Energy Technology Data Exchange (ETDEWEB)

Formulas are obtained for calculation of the energies and B(Elambda) values of T/sub greater-than/ giant resonances in the quasiparticle-phonon model of the nucleus. Characteristics of giant dipole resonances are calculated in several spherical nuclei and the correct location is obtained for T/sub less-than/ and T/sub greater-than/ collective 1/sup -/ states. The calculated ratios sigma/sub -/1(T/sub greater-than/)/sigma/sub -/1(T/sub less-than/) agree with the experimental data for /sup 88/Sr, /sup 90/Zr, and /sup 92/Mo and are 3 times larger than the experimental values for /sup 116,120,124/Sn. The decrease of the cross sections sigma/sub -/1(T/sub greater-than/) in /sup 124/Sn in comparison with /sup 116/Sn is correctly reproduced.

International Nuclear Information System (INIS)

Leptonic pair production on nuclei ad EMC-effect are discussed within the frames of the flucton model with scaling distortion. Cumulative production of direct photons and leptonic pairs as a test of the model of hard collisions is considered. The results of calculations of massive leptonic pair production cross sections on nucleus fluctons, caculations of the ratio of deuterium and iron structural functions, cross sections of direct photon production on sup(181)Ta nuclei at Esub(p)=400 GeV and cross section of #pi#-meson production in the model of hard collisions are presented. Experimental discovery of direct cumulative photons is concluded to be important for understanding the mechanism of parton hard scattering from nucleus fluctons.

International Nuclear Information System (INIS)

We consider particle evaporation and fission of an ensemble of hot, rotating compound nuclei as a stochastic process. We derive a set of coupled differential equations formed by a Fokker-Planck equation describing fission, and master equations for calculating particle evaporation. From these equations, we are able to determine multiplicities of prefission neutrons, protons and #alpha#-particles, their energy spectra and their angular momentum distributions. A comparison of our results with experimental data provides us with information regarding the reduced friction coefficient #beta#, the fission barrier height and the level density parameter. For different iridium isotopes, ("1"8"1","1"8"5","1"8"7Ir), "1"8"5Os and "1"5"8Er, we obtain as an upper limit #beta##<=#8.0x10"2"1 s"-"1. (orig.).

CERN Document Server

Determining the type of matter that is inside a neutron star (NS) has been a long-standing goal of astrophysics. Despite this, most of the NS equations of state (EOS) that predict maximum masses in the range 1.4-2.8 solar masses are still viable. Most of the precise NS mass measurements that have been made to date show values close to 1.4 solar masses, but a reliable measurement of an over-massive NS would constrain the EOS possibilities. Here, we investigate how optical astrometry at the microarcsecond level can be used to map out the orbits of High-Mass X-ray Binaries (HMXBs), leading to tight constraints on NS masses. While previous studies by Unwin and co-workers and Tomsick and co-workers discuss the fact that the future Space Interferometry Mission should be capable of making such measurements, the current work describes detailed simulations for 6 HMXB ...

British Library Electronic Table of Contents (United Kingdom)

A two-dimensional (2D) lattice model with anisotropic resonant microstructures is found to provide an anisotropic band gap structure. A 2D continuum with anisotropic effective mass density is introduced to represent this lattice system. Two methods are proposed to derive the equivalent continuum. In the first method, the effective mass density of the equivalent continuum is obtained by matching the dispersion relations for harmonic waves propagating in the principal directions. The second approach employs an approximate estimation of the effective mass density by volume-averaging an effective mass that represents the resonant microstructure. For both equivalent continuum models, the effective mass density is frequency-dependent and may become negative in certain frequency ranges. Subsequen...

International Nuclear Information System (INIS)

Surface photometry of bulges and elliptical galaxies is reviewed. The properties of cores and nuclei as revealed by improvements in seeing and the use of CCDs are examined, and newly discovered structural details such as dust, shells, and dynamical subsystems which show the importance of accretion events in galactic evolution are addressed. Improved constraints on galaxy formation resulting from better measurements of parameter scaling laws are discussed, and accurate measurements of departures from elliptical isophotes and of color gradients obtained with CCDs are considered.

International Nuclear Information System (INIS)

Quark models of production of cumulative particles and the EMC effect are analyzed. It is shown that all these models are characterized by a universal relation between the spectrum of cumulative nucleons and the cross section for cumulative particles containing valence quarks of the nucleus. This relation is tested for the deuteron, and the role of secondary nuclear processes for heavy nuclei is discussed. It is noted that the ''sea'' cumulative particles (K"-, p-bar) are particularly important for understanding the nature of the difference between the structure functions of a nucleus and of a free nucleon.

International Nuclear Information System (INIS)

The essential difference as well as the apparent identity between the triaxial-rotor model and the gamma-vibrational model have been discussed. From the gamma decay mode, the [19/2"-]_1 states of the j = 11/2"- family in "1"8"7Ir and "1"8"9Ir have been identified as the K = j + 4 states, the presence of which contradicts the particle plus triaxial-rotor model. (author).

International Nuclear Information System (INIS)

This review briefly describes current efforts to develop superradiant sources of coherent radiation for the sub-nanometer range of wavelenghs, using nuclear rather than the atomic or molecular transitions that are stimulated in existing lasers. First the radiative (including Raman) interactions of nuclei with those of atoms and molecules are compared; then the present status of research on the fundamental problems involved in stimulating nuclear gamma radiation is described. (author). 20 refs.; 2 figs.

Science.gov (United States)

A {sup 92}Mo beam with an energy of {ital E}/{ital A}=70 MeV has been used to produce new isotopes near the proton drip line. The Michigan State University National Superconducting Cyclotron Laboratory A1200 fragment separator was used to detect the new isotopes {sup 78}Y, {sup 82}Nb, {sup 85}Mo, {sup 86}Tc, and {sup 89,90}Ru.

UK PubMed Central (United Kingdom)

PCD (programmed cell death) in plants presents important morphological and biochemical differences compared with apoptosis in animal cells. This raises the question of whether PCD arose independently...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Ratio of the fissile isomers and prompt fissions yields has been measured in processes of neutron capture by /sup 241/Am and /sup 243/Am nuclei in the neutron energy interval from 0.2 up to 1.3 MeV. The present data and the previous results suggest that the fission Am isomers are spin structure isomers rather than shape isomers.

International Nuclear Information System (INIS)

The K"+- and K"-meson cumulative production cross sections are measured at 119"0 in the laboratory system on nuclei Be, Al, Cu and Ta bombarded by 10 GeV protons. Spectra of the K"-mesons consisting of only sea quarks show universal features characteristic of the spectra of cumulative particles, which contain valence quarks. Evidence is obtained for the fact that the energy density in a flucton can exceed the mean nuclear density by an order of magnitude.

International Nuclear Information System (INIS)

Low spin states (Jnuclei with a typical decoupling spectrum built on a single particle level j show systematic discrepancies between theory and experiment. To account for the discrepancies the decoupling scheme is extended to include also strong coupling. Excellent agreement including that for the low spin states is found in "1"8"7Ir to which this theory is applied. (Auth.).

Energy Technology Data Exchange (ETDEWEB)

Several low-mass models with an inhomogeneous radiative core and a convective envelope are investigated, the entire core or its upper portion being treated as a zone of neutral stability. Mixing by convective overshoot will then give rise to unstable structure.

CERN Document Server

We calculate the light `glueball' mass spectrum in N_f=2 lattice QCD using a fermion action that is non--perturbatively O(a) improved. We work at lattice spacings a~0.1 fm and with quark masses that range down to about half the strange quark mass. We find the statistical errors to be moderate and under control on relatively small ensembles. We compare our mass spectrum to that of quenched QCD at the same value of a. Whilst the tensor mass is the same (within errors), the scalar mass is significantly lighter in the dynamical lattice theory, by a factor of ~0.84 +/- 0.03. We discuss what the observed m_q dependence of this suppression tells us about the dynamics of glueballs in QCD. We also calculate the masses of flux tubes that wind around the spatial torus, and extract the string tension from these. As we decrease the quark ...

UK PubMed Central (United Kingdom)

BackgroundMass treatment to trachoma endemic communities is a critical part of the World Health Organization SAFE strategy. However, non-participation may not be at random, affecting...Full Text Available

UK PubMed Central (United Kingdom)

We have developed a method for dissecting single neurons from the nematode Ascaris suum, in order to determine their peptide content by mass spectrometry (MS). In this paper,...Full Text Available

UK PubMed Central (United Kingdom)

The first cell lineage specification in mouse embryo development is the formation of trophectoderm (TE) and inner cell mass (ICM) of the blastocyst. This article is to review and discuss the...Full Text Available

UK PubMed Central (United Kingdom)

Improved NMR detection of mass limited samples can be obtained by taking advantage of the mass sensitivity of microcoil NMR, while throughput issues can be addressed using multiple, parallel...Full Text Available

UK PubMed Central (United Kingdom)

Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MS) has been explored widely for DNA sequencing. The major requirement for this method is that the DNA sequencing fragments...Full Text Available

UK PubMed Central (United Kingdom)

The binding mode of telomestatin to G-quadruplex DNA has been investigated using electrospray mass spectrometry, by detecting the intact complexes formed in ammonium acetate. The mass measurements show...Full Text Available

UK PubMed Central (United Kingdom)

Discrete masses are commonly detected during mammographic screening and most such lesions are benign. For lesions without pathognomonically benign imaging features that are still regarded likely to...Full Text Available

UK PubMed Central (United Kingdom)

The validation parameters for pharmaceutical analyses were examined for the accelerator mass spectrometry measurement of ¹⁴C/C ratio, independent of chemical separation procedures....Full Text Available