Search results for "SCOPE"
showing 10 items of 2420 documents
Discovery of ten millisecond pulsars in the globular cluster 47 Tucanae
1991
IN the past four years a total of 13 millisecond pulsars have been found in 12 different globular clusters. These pulsars are believed to be old neutron stars that have been spun up ('recycled') in low-mass X-ray binary systems1 although some may have been formed by the accretion-induced collapse of white dwarfs in binaries2. The globular cluster 47 Tucanae has an especially dense core, and is therefore a likely site for millisecond pulsar formation. Using the Parkes radiotelescope, we have now detected ten addi-tional millisecond pulsars in 47 Tuc, more than half of which are members of binary systems. Almost half of the known millisecond pulsars and more than a quarter of the known binary…
Inhomogeneous-strain-induced magnetic vortex cluster in one-dimensional manganite wire
2020
Abstract Mixed-valance manganites with strong electron correlation exhibit strong potential for spintronics, where emergent magnetic behaviors, such as propagation of high-frequency spin waves and giant topological Hall Effects can be driven by their mesoscale spin textures. Here, we create magnetic vortex clusters with flux closure spin configurations in single-crystal La0.67Sr0.33MnO3 wire. A distinctive transformation from out-of-plane domains to a vortex state is directly visualized using magnetic force microscopy at 4 K in wires when the width is below 1.0 μm. The phase-field modeling indicates that the inhomogeneous strain, accompanying with shape anisotropy, plays a key role for stab…
Fine Thermal Structure of a Coronal Active Region
2007
著者人数：12名
PSR 1758 – 24 and G5.4 – 1.2, a remarkable pulsar–supernova remnant association
1991
Τiming observations made over an 18-month period using the Parkes radiotelescope show that the pulsar PSR 1758-24 is young and is located at the extreme western edge of the compact nebula G5.27-0.90 which is associated with supernova remnant G5.4-1.2. These results confirm the association of this pulsar with the supernova remnant. They also imply that the pulsar was born with such a high velocity that is has overtaken the supernova remnant shell and now lies outside the shell
Competition between Allowed and First-Forbidden β Decay: The Case of Hg208→Tl208
2020
The β decay of ^{208}Hg into the one-proton hole, one neutron-particle _{81}^{208}Tl_{127} nucleus was investigated at CERN-ISOLDE. Shell-model calculations describe well the level scheme deduced, validating the proton-neutron interactions used, with implications for the whole of the N>126, Z<82 quadrant of neutron-rich nuclei. While both negative and positive parity states with spin 0 and 1 are expected within the Q_{β} window, only three negative parity states are populated directly in the β decay. The data provide a unique test of the competition between allowed Gamow-Teller and Fermi, and first-forbidden β decays, essential for the understanding of the nucleosynthesis of heavy nuclei in…
Production of excited double hypernuclei via Fermi breakup of excited strange systems
2011
Precise spectroscopy of multi-strange hypernuclei provides a unique chance to explore the hyperon-hyperon interaction. In the present work we explore the production of excited states in double hypernuclei following the micro-canonical break-up of an initially excited double hypernucleus which is created by the absorption and conversion of a stopped $\Xi^{-}$ hyperon. Rather independent on the spectrum of possible excited states in the produced double hypernuclei the formation of excited states dominates in our model. For different initial target nuclei which absorb the $\Xi^-$, different double hypernuclei nuclei dominate. Thus the ability to assign the various observable $\gamma$-transitio…
Timing in a FLASH
2017
Abstract A prototype detector, called FLASH (Fast Light Acquiring Start Hodoscope), was built to provide precise Time-of-Flight (TOF) measurements and reference timestamps for detector setups at external beam lines. Radiator bars, made of synthetic fused silica, were coupled to a fast MCP-PMT with 64 channels and read out with custom electronics using Time-over-Threshold (TOT) for signal characterization. The TRB3 system, a high-precision TDC implemented in an FPGA, was used as data acquisition system. The performance of a system consisting of two FLASH units was investigated at a dedicated test experiment at the Mainz Microtron (MAMI) accelerator using its 855 MeV electron beam. The TOT me…
Development and calibration of the tracking Compton/Pair telescope MEGA
2005
Abstract We describe the development and tests of the prototype for a new telescope for Medium Energy Gamma-ray Astronomy (MEGA) in the energy band 0.4–50 MeV. As a successor to COMPTEL and EGRET (at low energies), MEGA aims to improve the sensitivity for astronomical sources by at least an order of magnitude. It could thus fill the severe sensitivity gap between scheduled or operating hard-X-ray and high-energy gamma-ray missions and open the way for a future Advanced Compton Telescope. MEGA records and images γ-rays by completely tracking Compton and Pair creation events in a stack of double-sided Si-strip track detectors surrounded by a pixelated CsI calorimeter. A scaled down prototype …
Electromagnetic Production of the Hypertriton
1996
Kaon photoproduction on He3, gamma + He3 --> K+ + Hypertriton, is studied in the framework of the impulse approximation. Realistic He3 wave functions obtained as solutions of Faddeev equations with the Reid soft-core potential are used along with different Hypertriton wave functions. Results are compared for several elementary operator models, which can successfully describe the elementary kaon production off the proton up to a photon lab energy of k = 2.2 GeV. It is found that the corresponding cross sections are small, of the order of several nanobarns. It is also shown that the influence of Fermi motion is important, while the effect of different off-shell assumptions on the cross sec…
Microscopic quasiparticle-phonon description of odd-mass127−133Xeisotopes and their β decay
1998
Quasiparticle-phonon equations of motion are solved starting from a microscopic realistic many-body Hamiltonian. In this microscopic quasiparticle-phonon model (MQPM) the relevant part of the three-quasiparticle Hilbert space may possibly be taken into account even in calculations using large single-particle bases. As an example, the MQPM is applied to the calculation of energy levels and Fermi and Gamow-Teller beta-decay transition amplitudes for transitions between odd-mass ${}^{127\ensuremath{-}133}\mathrm{Xe}$, ${}^{127\ensuremath{-}133}\mathrm{I}$, and ${}^{127\ensuremath{-}133}\mathrm{Cs}$ isotopes. Considering the fully microscopic nature of the MQPM, comparison of its results and da…