Search results for "beam"
showing 10 items of 2126 documents
Competition of fission with the population of the yrast superdeformed band in $^{194}$Pb
1999
The 194Pb yrast superdeformed band has been populated in two reactions induced by two different beams delivered by the JYFL cyclotron. These two reactions differ in the asymmetry ratio (i.e. the ratio of the target mass over the projectile one) by more than a factor 3. For the first time, a superdeformed band of the A≈190 mass region has been populated using such a very heavy beam, namely 74Ge.
Compact dielectric reflective elements II Multichannel filter of closely spaced spectral bands
1994
The optical design of an interference wedge filter providing the simultaneous separation of a number of closely spaced spectral bands is studied. Multiple reflections of the incident collimated beam within the wedge are initiated, each of them characterized by a different angle of incidence and consequently by specific spectral parameters of the transmitted band. Model calculations based on the measured angular dependences of filter transmission parameters have been performed. The design is proposed for applications in optical communications (wavelength division demultiplexing), analytical spectroscopy (minipolychromators), color analysis, and similar areas.
Search for elements 119 and 120
2020
A search for production of the superheavy elements with atomic numbers 119 and 120 was performed in the 50Ti+249Bk and 50Ti+249Cf fusion-evaporation reactions, respectively, at the gas-filled recoil separator TASCA at GSI Darmstadt, Germany. Over four months of irradiation, the 249Bk target partially decayed into 249Cf, which allowed for a simultaneous search for both elements. Neither was detected at cross-section sensitivity levels of 65 and 200 fb for the 50Ti+249Bk and 50Ti+249Cf reactions, respectively, at a midtarget beam energy of Elab=281.5 MeV. The nonobservation of elements 119 and 120 is discussed within the concept of fusion-evaporation reactions including various theoretical pr…
Imperfect symmetry breaking
2018
By considering a nonlinear resonator driven by an elliptically polarized beam, we study experimentally the robustness of spontaneous symmetry breaking to controlled asymmetries. In particular, we reveal that different asymmetries can balance each other.
First Observation of the Unbound NucleusNe15
2014
We report on the first observation of the unbound proton-rich nucleus Ne-15. Its ground state and first excited state were populated in two-neutron knockout reactions from a beam of 500 MeV/u Ne-17. The Ne-15 ground state is found to be unbound by 2.522(66) MeV. The decay proceeds directly to O-13 with simultaneous two-proton emission. No evidence for sequential decay via the energetically allowed 2(-) and 1(-) states in F-14 is observed. The Ne-15 ground state is shown to have a strong configuration with two protons in the (sd) shell around O-13 with a 63(5)% (1s(1/2))(2) component.
Application of optical tomography for measurements of aeration parameters in large water tanks
2003
The paper presents a design and application study of a prototype optical tomograph for the detection and definition of shapes of gas bubbles moving in a liquid. In the applied method of measurements, the column is exposed to a homogeneous light beam and next the ray is detected with the use of optical waveguided detectors. Spatial reconstruction of the bubble shapes is done on the basis of the signals coming from two perpendicular systems of detectors. The bubble shape is approximated by an ellipsoid with suitably determined semi-axes and with the use of genetic algorithms based on the neuron network. Influence of the structure and dynamics of the measuring path on errors in representation …
Recent results on heavy-ion direct reactions of interest for 0νββ decay at INFN - LNS
2020
Abstract Neutrinoless double beta decay of nuclei, if observed, would have important implications on fundamental physics. In particular it would give access to the effective neutrino mass. In order to extract such information from 0νββ decay half-life measurements, the knowledge of the Nuclear Matrix Elements (NME) is of utmost importance. In this context the NUMEN and the NURE projects aim to extract information on the NME by measuring cross sections of Double Charge Exchange reactions in selected systems which are expected to spontaneously decay via 0νββ. In this work an overview of the experimental challenges that NUMEN is facing in order to perform the experiments with accelerated beams…
Intensity noise-driven nonlinear fiber polarization scrambler
2014
We propose and analyze a novel all-optical fiber polarization scrambler based on the transfer (via the Kerr effect) of the intensity fluctuations of an incoherent pump beam into polarization fluctuations of a frequency-shifted signal beam, copropagating in a randomly birefringent telecom fiber. Optimal signal polarization scrambling results whenever the input signal and pump beams have nearly orthogonal states of polarization. The nonlinear polarization scrambler may operate on either cw or high-bit-rate pulsed signals.
Spatial Beam Evolution in Nonlinear Multimode Fibers
2021
We discuss some recent results illustrating the role of input wave-front shaping, propagation dynamics and output beam diagnostics in order to observe spatial beam cleaning in nonlinear multimode fibers and amplifiers.
Lifetime Measurements of Low-lying States in $^{73}$Ga and $^{70,72,74}$Zn Isotopes
2019
International audience; Lifetimes of low-lying states in 73Ga and 70,72,74Zn were measured using the Recoil Distance Doppler Shift (RDDS) method. These nuclei were produced in deep-inelastic reactions in inverse kinematics with a 208Pb beam impinging on a 76Ge target. Prompt γ rays were detected using the AGATA tracking array coupled to the VAMOS++ spectrometer. Lifetime of the 5/2 − state in 73Ga, measured for the first time, provides additional evidence for the existence of a 1/2 −, 3/2 − ground-state doublet. The lifetimes of the 4 + states in 70,72,74Zn were remeasured in an attempt to understand the discrepancies observed between earlier measurements. Our results are in agreement with …