Search results for "SIP"
showing 10 items of 1280 documents
Analysis of the Intermediate-State Contributions to Neutrinoless Double β− Decays
2016
A comprehensive analysis of the structure of the nuclear matrix elements (NMEs) of neutrinoless double beta-minus (0νβ-β-) decays to the0+ground and first excited states is performed in terms of the contributing multipole states in the intermediate nuclei of0νβ-β-transitions. We concentrate on the transitions mediated by the light (l-NMEs) Majorana neutrinos. As nuclear model we use the proton-neutron quasiparticle random-phase approximation (pnQRPA) with a realistic two-nucleon interaction based on the Bonn one-boson-exchangeGmatrix. In the computations we include the appropriate short-range correlations, nucleon form factors, and higher-order nucleonic weak currents and restore the isospi…
Latest results from the EbyE NLO EKRT model
2017
We review the results from the event-by-event next-to-leading order perturbative QCD + saturation + viscous hydrodynamics (EbyE NLO EKRT) model. With a simultaneous analysis of LHC and RHIC bulk observables we systematically constrain the QCD matter shear viscosity-to-entropy ratio eta/s(T), and test the initial state computation. In particular, we study the centrality dependences of hadronic multiplicities, pT spectra, flow coefficients, relative elliptic flow fluctuations, and various flow-correlations in 2.76 and 5.02 TeV Pb+Pb collisions at the LHC and 200 GeV Au+Au collisions at RHIC. Overall, our results match remarkably well with the LHC and RHIC measurements, and predictions for the…
Detector characterization and first coincidence tests of a Compton telescope based on LaBr3 crystals and SiPMs
2011
International audience; A Compton telescope for dose monitoring in hadron therapy consisting of several layers of continuous LaBr3 crystals coupled to silicon photomultiplier (SiPM) arrays is under development within the ENVISION project. In order to test the possibility of employing such detectors for the telescope, a detector head consisting of a continuous 16 mm×18 mm×5 mm LaBr3 crystal coupled to a SiPM array has been assembled and characterized, employing the SPIROC1 ASIC as readout electronics. The best energy resolution obtained at 511 keV is 6.5% FWHM and the timing resolution is 3.1 ns FWHM. A position determination method for continuous crystals is being tested, with promising res…
High resolution detectors based on continuous crystals and SiPMs for small animal PET
2012
International audience; Sensitivity and spatial resolution are the two main factors to maximize in emission imaging. The improvement of one factor deteriorates the other with pixelated crystals. In this work we combine SiPM matrices with monolithic crystals, using an accurate γ-ray interaction position determination algorithm that provides depth of interaction. Continuous crystals provide higher sensitivity than pixelated crystals, while an accurate interaction position determination does not degrade the spatial resolution. Monte Carlo simulations and experimental data show good agreement both demonstrating sub-millimetre intrinsic spatial resolution. A system consisting in two rotating det…
On the performances of a particle tracking detector based on triangular scintillator bars read out by silicon photomultipliers
2020
Abstract A tracking detector composed of scintillator bars with a triangular cross-section read out by silicon photomultipliers in analog mode was developed. The tracker was designed to instrument a low density spectrometer for neutrino experiments. The performance of the system has been studied by exposing it to charged particle beams at the CERN-PS. The tests have shown that the position resolution in reconstructing charged particles’ tracks is within 2.2 mm over the momentum range 0.5–10 GeV/c.
Properties of nuclei in the nobelium region studied within the covariant, Skyrme, and Gogny energy density functionals
2015
We calculate properties of the ground and excited states of nuclei in the nobelium region for proton and neutron numbers of 92 <= Z <= 104 and 144 <= N <= 156, respectively. We use three different energy-density-functional (EDF) approaches, based on covariant, Skyrme, and Gogny functionals, each within two different parameter sets. A comparative analysis of the results obtained for odd-even mass staggerings, quasiparticle spectra, and moments of inertia allows us to identify single-particle and shell effects that are characteristic to these different models and to illustrate possible systematic uncertainties related to using the EDF modelling
High performance detector head for PET and PET/MR with continuous crystals and SiPMs
2012
International audience; A high resolution PET detector head for small animal PET applications has been developed. The detector is composed of a 12 mm x 12 mm source continuous LYSO crystal coupled to a 64-channel monolithic SiPM matrix from FBK-irst. Crystal thicknesses of 5 mm and 10 mm have been tested, both yielding an intrinsic spatial resolution around 0.7 mm FWHM with a position determination algorithm that can also provide depth-of-interaction information. The detectors have been tested in a rotating system that makes it possible to acquire tomographic data and reconstruct images of 22Na sources. An image reconstruction method specifically adapted for continuous crystals has been emp…
Experiments on Fission Dynamics with Relativistic Heavy-ion Beams
2002
[Abstract] At GSI, Darmstadt, an experimental program on fission with relativistic heavy-ion beams is in progress. A large range of excitation energies, combined with low angular momentum and small shape distortion is accessible. Full nuclide identification of the reaction residues is achieved by applying inverse kinematics. The nuclide production and the kinematics of fission fragments from a variety of primordial and radioactive projectiles reveal new insight into the influence of shell effects and dissipation on the fission process. The present contribution gives an overview on the experimental methods, the experimental results and the prospects for future progress.
Nuclear structure of97Y in the interacting boson-fermion model
1988
Unique-parity states of97Y are studied in the framework of the interacting boson-fermion model (IBFM). Spin assignments for the levels of the unique-parity yrast band are proposed on the basis of nuclear systematics and the IBFM band pattern associated with coupling of a particle-type quasiparticle (g9/2) to the SU(5) core3896Sr58. The good fit of the experimental data with the IBFM calculations confirms the single particle character of this immediate neighbour of the doubly sub-magic nucleus96Zr.
Investigation of the ββ decay of 116Cd into excited states of 116Sn
1994
Abstract The double-beta decay of 116Cd into excited states of 116Sn is experimentally and theoretically investigated. From an inclusive experiment, using an external source of isotopically enriched Cd, new most stringent limits for the allowed and non-standard-model decays into excited states are derived. It is further investigated whether the bremsstrahlung emitted by the ββ electrons can be used to derive information on the ground-state decay. For the two-neutrino-decay mode a calculation, using the quasiparticle random-phase approximation, shows that the disadvantage in phase space, in comparison to the ground-state decay, is partially compensated through the nuclear-matrix element. Exp…