Limits on the low energy antinucleon-nucleus annihilations from the Heisenberg principle

We show that the quantum uncertainty principle puts some limits on the effectiveness of the antinucleon-nucleus annihilation at very low energies. This is caused by the fact that the realization a very effective short-distance reaction process implies information on the relative distance of the reacting particles. Some quantitative predictions are possible on this ground, including the approximate A-independence of antinucleon-nucleus annihilation rates.Comment: 10 pages, no figure

A new Monte Carlo muon generator for cosmic-ray muon applications

Cosmic rays, thanks to their ubiquity and high penetration capability, have been successfully used in scientific research ever since their discovery. As soon as their knowledge improved, applications in the civil/environmental field were also developed: muon radiography (or muography, based on the flux attenuation) and muon tomography (based on the scattering angle) have been used to study the inner structure of volcanoes, to seek hidden rooms in Egyptian pyramids, to search for heavy metals in containers, and so on. And besides these imaging techniques, cosmic ray muons are also widely used for detector testing and alignment practically in every Nuclear Physics or Particle Physics experiment. Since most of these applications are sensitive to the angular and momentum distribution of cosmic muons, an accurate modelling of these distributions is a key feature for any generation tool conceived to simulate the cosmic muon flux. This can make the generator quite time-consuming, which is a strong limit when one needs to reach high statistics or to study large structures. A new Monte Carlo generator for cosmic-ray muons, named Efficient COsmic MUon Generator (EcoMug for short), especially designed to be fast (≳ 10^5 muons generated per second on a standard machine) without losing accuracy, is presented here. It is written as a header-only C++11 library, ready to be integrated into whatever C++ code, in particular C++ code based on Geant4 simulation tool. By default, EcoMug relies on a simple and effective parametrisation of the experimental data of cosmic ray differential flux at sea level, taken from the literature, but the library is written in such a way that every user can easily replace it with his own user-defined parametrisation. Unlike other tools, EcoMug is able to generate muons from different kind of surfaces (plane, cylinder and half-sphere), while keeping the correct angular and momentum distribution of generated tracks inside a fiducial volume. This allows to optimise the generation surface according to the system under study, and leads to a further improvement of the overall simulation efficiency. In this contribution we will present the main features of EcoMug, starting from its mathematical foundation, and eventually showing some interesting applications

Investigating the possibility of leakage detection in water distribution networks using cosmic ray neutrons in the thermal region

Water distribution systems can experience high levels of leakage, originating from different sources, such as deterioration due to aging of pipes and fittings, material defects, and corrosion. In addition to causing financial losses and supply problems, leakages in treated water distribution also represent a risk for public health. Despite several techniques for leak detection are already available, there is still a lot of interest in new non-invasive approaches, especially for scenarios where acoustic techniques struggle, such as in noisy environmental conditions. In this work we investigated the possibility of using cosmic ray (CR) neutrons for the detection of underground leakages in water distribution networks, by exploiting the difference in the above ground thermal neutron flux between dry and wet soil conditions. The potential of the technique has been assessed by means of an extensive set of Monte Carlo simulations based on GEANT4, involving realistic scenarios based on the Italian aqueduct design guidelines. Simulation studies focused on sandy soils and results suggest that a significative signal, associated with a leakage, could be detected with a data-taking lasting from a few minutes to a half-hour, depending on the environmental soil moisture, the leaking water distribution in soil, and the soil chemical composition. Finally, a brief description of a new portable and low-cost detector for thermal neutrons, currently under commission, is also presented

Una procedura per la valutazione dei limiti di utilizzo di O-Ring sottoposti ad intensi fasci di neutroni

Si presenta una procedura per la previsione della durata di utilizzo di O-ring in materiale polimerico impiegati nei bersagli per la produzione di fasci di ioni radioattivi. Si sono dapprima condotte prove di tenuta a vuoto e analisi a elementi finiti di un O-ring di riferimento operante con diversi livelli di interferenza con la cava, identificando la precompressione limite per la tenuta e la corrispondente pressione di contatto con la cava. Si sono poi effettuate prove di trazione e di Compression Set su campioni di O-ring in EPDM, preventivamente sottoposti a diversi livelli di irraggiamento in campi misti di neutroni e gamma, analizzando l’effetto della dose assorbita sul comportamento meccanico del materiale e sulle corrispondenti proprietà resistenziali, e definendo opportune leggi costitutive. Si sono infine simulate le progressive modifiche di comportamento della guarnizione indotte dall’irraggiamento, prevedendone la durata in esercizio in termini di tenuta e di resistenza strutturale

First determination of the one-proton induced Non-Mesonic Weak Decay width of p-shell {\Lambda}-Hypernuclei

Previous studies of proton and neutron spectra from Non-Mesonic Weak Decay of eight Lambda-Hypernuclei (A = 5-16) have been revisited. New values of the ratio of the two-nucleon and the one-proton induced decay widths, Gamma_2N/Gamma_p, are obtained from single proton spectra, Gamma_2N/Gamma_p = 0.50 +/- 0.24, and from neutron and proton coincidence spectra, Gamma_2N/Gamma_p = 0.36 +/- 0.14stat +0.05sys -0.04sys , in full agreement with previously published ones. With these values, a method is developed to extract the one-proton induced decay width in units of the free Lambda decay width, Gamma_p/Gamma_Lambda, without resorting to Intra Nuclear Cascade models but by exploiting only experimental data, under the assumption of a linear dependence on A of the Final State Interaction contribution. This is the first systematic determination ever done and it agrees within the errors with recent theoretical calculations.Comment: 16 pages, 3 figures, 2 table

A major QTL is associated with berry grape texture characteristics

Berry texture and berry skin mechanical properties are traits with high agronomic relevance because they are related to quality parameters and marketing requirements of wine, table, and raisin grapes. Searching for QTLs linked to berry texture, an F1 population of 152 individuals and their parents were used in this study. These F1 plants were obtained crossing Raboso Veronese, a seeded black wine grape cultivar, and Sultanina, a seedless white grape variety, especially used for raisins. Density flotation was applied for berry sorting improving the management of many and highly variable genotypes, irrespective of the quantification of specific molecule classes. Berries were evaluated for technological ripeness parameters and mechanical properties. Texture parameters were taken as raw data and as data normalised on berry dimensions, i.e., berry diameter or surface or volume. SSR molecular markers were used to produce a genetic map and a major QTL for berry texture was found on chromosome 18 with traits related to berry firmness showing a phenotypical explained variance higher than 60 %, and traits related to berry resilience, springiness and cohesiveness showing a variance higher than 50 %. Surprisingly, this QTL showed to be associated with SSR markers linked to VviAGL11, the main gene linked to seedlessness. VviAGL11 expression and co-expression profiling during grape ripening was evaluated using available information; this data suggested a role for this gene on the texture of a ripe berry

AEGIS at CERN: Measuring Antihydrogen Fall

The main goal of the AEGIS experiment at the CERN Antiproton Decelerator is the test of fundamental laws such as the Weak Equivalence Principle (WEP) and CPT symmetry. In the first phase of AEGIS, a beam of antihydrogen will be formed whose fall in the gravitational field is measured in a Moire' deflectometer; this will constitute the first test of the WEP with antimatter.Comment: Presented at the Fifth Meeting on CPT and Lorentz Symmetry, Bloomington, Indiana, June 28-July 2, 201

Proton spectra from Non-Mesonic Weak Decay of p-shell Lambda-Hypernuclei and evidence for the two-nucleon induced process

New spectra from the FINUDA experiment of the Non Mesonic Weak Decay (NMWD) proton kinetic energy for 9(Lambda)Be, 11(Lambda)B, 12(Lambda)C, 13(Lambda)C, 15 (Lambda)N and 16(Lambda)O are presented and discussed along with the published data on 5(Lambda)He and 7(Lambda)Li. Exploiting the large mass number range and the low energy threshold (15 MeV) for the proton detection of FINUDA, an evaluation of both Final State Interactions (FSI) and the two nucleon induced NMWD contributions to the decay process has been done. Based on this evaluation, a linear dependence of FSI on the hypernuclear mass number A is found and for the two nucleon stimulated decay rate the experimental value of Gamma2/Gammap=0.43+-0.25 is determined for the first time. A value for the two nucleon stimulated decay rate to the total decay rate Gamma2/GammaNMWD=0.24+-0.10 is also extracted.Comment: 11 pages and 2 figure

Modified Vitrectomy Technique for Phakic Rhegmatogenous Retinal Detachment with Intermediate Break

Purpose. To evaluate the effects of a modification of the traditional 25-gauge pars plana vitrectomy technique in the treatment of uncomplicated macula-on rhegmatogenous retinal detachment (RRD) with intermediate retinal break(s) and marked vitreous traction in the phakic eye. Methods. Prospective, noncomparative, and interventional case series. All consecutive phakic eyes with primary uncomplicated macula-on RRD with intermediate retinal break(s) and marked vitreous traction, with at least 1 year of postoperative follow-up, were enrolled. In all eyes, “localized 25-gauge vitrectomy” under air infusion with localized removal of the vitreous surrounding the retinal break(s), in association with laser photocoagulation and air tamponade, was performed. The primary end point was the rate of primary retinal attachment. Secondary end points were cataract progression and assessed by digital Scheimpflug lens photography (mean change of nuclear density units) and the rate of complications. Results. Thirty-two phakic eyes were included in the final analysis. At 12 months, the primary outcome of anatomical success was achieved in 94% of eyes. The mean nuclear density units did not change significantly at any time point during the follow-up. After localized vitrectomy, one eye developed an epiretinal membrane, and one eye developed cystoid macular edema; no other significant complications were reported. Conclusions. “Localized vitrectomy” has a high anatomical success rate in phakic eyes with primary uncomplicated macula-on RRD with intermediate retinal break(s) and marked vitreous traction, without causing progression of cataract