69 research outputs found
Applications of nuclear physics to energy: the INFN-E project of the National Institute of Nuclear Physics (INFN)
Journal of Instrumentation article to appear in Proceedings of the 2nd International Workshop on Proton-Boron Fusion, 5-8 September, 2022, Four Points by Sheraton and INFN-LNS, Catania, Ital
A useful observable for estimating keff in fast subcritical systems
The neutron multiplication factor k-eff is a key quantity to characterize subcritical neutron multiplying devices and for understanting their physical behaviour, being related to the fundamental eigenvalue of Boltzmann transport equation. Both the maximum available power-and all quantities related to it, like, e.g. the effectiveness in burning nuclear wastes-as well as reactor kinetics and dynamics depend on k-eff. Nevertheless , k e f f is not directly measurable and its determination results from the solution of an inverse problem: minimizing model dependence of the solution for k-eff then becomes a critical issue, relevant both for practical and theoretical reasons
Characterization of LAPPD timing at CERN PS testbeam
Large Area Picosecond PhotoDetectors (LAPPDs) are photosensors based on
microchannel plate technology with about 400 cm sensitive area. The
external readout plane of a capacitively coupled LAPPD can be segmented into
pads providing a spatial resolution down to 1 mm scale. The LAPPD signals have
about 0.5 ns risetime followed by a slightly longer falltime and their
amplitude reaches a few dozens of mV per single photoelectron. In this article,
we report on the measurement of the time resolution of an LAPPD prototype in a
test beam exercise at CERN PS. Most of the previous measurements of LAPPD time
resolution had been performed with laser sources. In this article we report
time resolution measurements obtained through the detection of Cherenkov
radiation emitted by high energy hadrons. Our approach has been demonstrated
capable of measuring time resolutions as fine as 25-30 ps. The available
prototype had performance limitations, which prevented us from applying the
optimal high voltage setting. The measured time resolution for single
photoelectrons is about 80 ps r.m.s.Comment: 35 pages, 23 figure
photoproduction on the proton for photon energies from 0.725 to 2.875 GeV
Differential cross sections for the reaction have been
measured with the CEBAF Large Acceptance Spectrometer (CLAS) and a tagged
photon beam with energies from 0.725 to 2.875 GeV. Where available, the results
obtained here compare well with previously published results for the reaction.
Agreement with the SAID and MAID analyses is found below 1 GeV. The present set
of cross sections has been incorporated into the SAID database, and exploratory
fits have been made up to 2.7 GeV. Resonance couplings have been extracted and
compared to previous determinations. With the addition of these cross sections
to the world data set, significant changes have occurred in the high-energy
behavior of the SAID cross-section predictions and amplitudes.Comment: 18 pages, 10 figure
A new multianodic large area photomultiplier to be used in underwater neutrino detectors
In this article we describe the properties of a new 10-in. hemispherical photomultiplier manufactured by Hamamatsu. The prototype has a segmented photocathode and four independent amplification stages. The photomultiplier is one of the main components of a newly designed direction-sensitive optical module to be employed in large-scale underwater neutrino telescopes. The R&D activity has been co-funded by the INFN and the KM3NeT Consortium. The prototype performance fully meets with the design specifications
Photodisintegration of He into p+t
The two-body photodisintegration of He into a proton and a triton has
been studied using the CEBAF Large-Acceptance Spectrometer (CLAS) at Jefferson
Laboratory. Real photons produced with the Hall-B bremsstrahlung-tagging system
in the energy range from 0.35 to 1.55 GeV were incident on a liquid He
target. This is the first measurement of the photodisintegration of He
above 0.4 GeV. The differential cross sections for the He
reaction have been measured as a function of photon-beam energy and
proton-scattering angle, and are compared with the latest model calculations by
J.-M. Laget. At 0.6-1.2 GeV, our data are in good agreement only with the
calculations that include three-body mechanisms, thus confirming their
importance. These results reinforce the conclusion of our previous study of the
three-body breakup of He that demonstrated the great importance of
three-body mechanisms in the energy region 0.5-0.8 GeV .Comment: 13 pages submitted in one tgz file containing 2 tex file and 22
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