Search results for "Orbital"

Laser Spectroscopy of Neutron-Rich Hg207,208 Isotopes: Illuminating the Kink and Odd-Even Staggering in Charge Radii across the N=126 Shell Closure

2021

The mean-square charge radii of $^{207,208}$Hg ($Z=80, N=127,128$) have been studied for the first time and those of $^{202,203,206}$Hg ($N=122,123,126$) remeasured by the application of in-source resonance-ionization laser spectroscopy at ISOLDE (CERN). The characteristic \textit{kink} in the charge radii at the $N=126$ neutron shell closure has been revealed, providing the first information on its behavior below the $Z=82$ proton shell closure. A theoretical analysis has been performed within relativistic Hartree-Bogoliubov and non-relativistic Hartree-Fock-Bogoliubov approaches, considering both the new mercury results and existing lead data. Contrary to previous interpretations, it is d…

The influence of quasineutron configurations on 161Ta and nearby odd-A Nuclei

2011

Several strongly coupled bands in the neutron‐deficient nucleus 161Ta have been identified and quasiparticle configuration assignments have been made on the basis of rotational alignments and cranked shell model calculations. The level scheme elucidated for 161Ta highlights the competition between the ν(h9/2) and ν(i13/2) orbitals to form the yrast spectrum. The band structures in 161Ta also provide new insights into the structural features of other heavy odd‐A nuclei populated with much lower reaction cross sections in this region at the proton drip line.

Generating highly squeezed Hybrid Laguerre-Gauss modes in large-Fresnel-number Degenerate Optical Parametric Oscillators

2008

We theoretically describe the quantum properties of a large Fresnel number degenerate optical parametric oscillator with spherical mirrors that is pumped by a Gaussian beam. The resonator is tuned so that the resonance frequency of a given transverse mode family coincides with the down-converted frequency. After demonstrating that only the lower orbital angular momentum (OAM) Laguerre-Gauss modes are amplified above threshold, we focus on the quantum properties of the rest of (classically empty) modes. We find that combinations of opposite OAM (Hybrid Laguerre-Gauss modes) can exhibit arbitrary large quadrature squeezing for the lower OAM non amplified modes.

New subshell closure atN=58emerging in neutron-rich nuclei beyondNi78

2010

The structure of neutron-rich nuclei beyond $^{78}\mathrm{Ni}$ was studied using postaccelerated radioactive beams of $^{83,84,85}\mathrm{Ga}$ utilizing $\ensuremath{\beta} \ensuremath{\gamma}$ and $\ensuremath{\beta}\ensuremath{-}n \ensuremath{\gamma}$ spectroscopy. Our data, when combined with energy level systematics, suggests a possible new spherical subshell closure at $N=58$ is created by the nearly degenerated $\ensuremath{\nu}3{s}_{1/2}$ and $\ensuremath{\nu}2{d}_{5/2}$ orbitals being well separated from other orbitals above $N=50$. The near degeneracy of these states could be evidenced by isomerism in this region. The energies of the ${2}_{1}^{+}$ and proposed ${4}_{1}^{+}$ states …

Legri Background. Short Term Variability

2001

Background modelling for LEO satellites with high orbital inclination is not an easy task. The diffuse background component is dominated by the background coming from strong interactions with Earth magnetosphere trapped particles. Magnetic shielding is variable along the orbits and crosses through the SAA induce high radioactivity decay counting ratios. The aim of this paper is to present a model for the background total counting ratio of the 17 operative CdZnTe detectors on LEGRI in the short time scales and for observing periods outside crosses through SAA having enough time to cool LEGRI after the last SAA transit. Fluxes measured have been modelled in terms of the Mcllwain parameter L u…

BeppoSAX serendipitous discovery of the X-ray pulsar SAX J1802.7-2017

2003

We report on the serendipitous discovery of a new X-ray source, SAX J1802.7-2017, ~22' away from the bright X-ray source GX 9+1, during a BeppoSAX observation of the latter source on 2001 September 16-20. SAX J1802.7-2017 remained undetected in the first 50 ks of observation; the source count rate in the following ~300 ks ranged between 0.04 c/s and 0.28 c/s, corresponding to an averaged 0.1-10 keV flux of 3.6 10^{-11} ergs cm^{-2} s^{-1}. We performed a timing analysis and found that SAX J1802.7-2017 has a pulse period of 139.612 s, a projected semimajor axis of a_x sin i ~ 70 lt-s, an orbital period of ~4.6 days, and a mass function f(M) ~ 17 Msun. The new source is thus an accreting X-ra…

The complex enviroment around Cir X-1

2008

We present the results of an archival 54 ks long Chandra observation of the peculiar source Cir X–1 during the phase passage 0.223-0.261, based on the phase zero passage at the periastron, of its orbital period. We focus on the study of detected emission and absorption features using the High Energy Transmission Grating Spectrometer on board of the Chandra satellite. A comparative analysis of X-ray spectra, selected at different flux levels of the source, allows us to distinguish between a very hard state, at a low countrate, and a brighter, softer, highly absorbed spectrum during episodes of flaring activity, when the unabsorbed source luminosity is about three times the value in the hard …

JEM-X: three years in space

2006

We report on the technical and scientific performance of JEM-X, the X-ray monitor on ESA's INTEGRAL mission. INTEGRAL has now been in orbit for more than three years, and the mission is foreseen to be extended until the end of 2010. Overall, JEM-X performs very well, and can be expected to continue to do so for the duration of the mission. We discuss in some detail the operational experiences and the problems encountered with the microstrip detectors caused by the space environment and give one example of the interesting scientific results obtained. The analysis software is still being improved on, and we discuss briefly the significance of these improvements.

2015

Advanced Astronomy for Heliophysics Plus (ADAHELI+) is a project concept for a small solar and space weather mission with a budget compatible with an European Space Agency (ESA) S-class mission, including launch, and a fast development cycle. ADAHELI+ was submitted to the European Space Agency by a European-wide consortium of solar physics research institutes in response to the "Call for a small mission opportunity for a launch in 2017," of March 9, 2012. The ADAHELI+ project builds on the heritage of the former ADAHELI mission, which had successfully completed its phase-A study under the Italian Space Agency 2007 Small Mission Programme, thus proving the soundness and feasibility of its in…

An eclipsing millisecond pulsar in the globular cluster Terzan 5

1990

WE HAVE discovered an eclipsing binary millisecond pulsar in the globular cluster Terzan 5. This, the second known eclipsing binary pulsar after PSR1957 + 20, has a pulse period of 11.56 ms and a very short orbital period of 1.8 hours. In contrast to PSR1957 + 20, where the eclipses occupy about 10 per cent of the orbital period1, the eclipse duration in this pulsar is very variable and never less than one-third of the orbital period. The pulsar is in a circular orbit of radius 0.11 light seconds, which implies a minimum companion mass of 0.089 solar masses, about four times the companion mass of PSR1957 + 20. Timing observations suggest an identification of the pulsar with a variable conti…