Neutral kaon pairs produced in ϕ decays in anti-symmetric entangled state can be exploited to search for violation of CPT symmetry and Lorentz invariance. We present an analysis of the CP-violating ...process ϕ→KSKL→π+π−π+π− based on 1.7 fb−1 of data collected by the KLOE experiment at the Frascati ϕ-factory DAΦNE. The data are used to perform a measurement of the CPT-violating parameters Δaμ for neutral kaons in the context of the Standard Model Extension framework. The parameters measured in the reference frame of the fixed stars are:Δa0=(−6.0±7.7stat±3.1syst)×10−18 GeV,ΔaX=(0.9±1.5stat±0.6syst)×10−18 GeV,ΔaY=(−2.0±1.5stat±0.5syst)×10−18 GeV,ΔaZ=(3.1±1.7stat±0.5syst)×10−18 GeV. These are presently the most precise measurements in the quark sector of the Standard Model Extension.
One of the critical aspects for the accurate determination of neutron capture cross sections when combining time-of-flight and total energy detector techniques is the characterization and control of ...systematic uncertainties associated to the measuring devices. In this work we explore the most conspicuous effects associated to harsh count rate conditions: dead-time and pile-up effects. Both effects, when not properly treated, can lead to large systematic uncertainties and bias in the determination of neutron cross sections. In the majority of neutron capture measurements carried out at the CERN n_TOF facility, the detectors of choice are the C6D6 liquid-based either in form of large-volume cells or recently commissioned sTED detector array, consisting of much smaller-volume modules. To account for the aforementioned effects, we introduce a Monte Carlo model for these detectors mimicking harsh count rate conditions similar to those happening at the CERN n_TOF 20 m flight path vertical measuring station. The model parameters are extracted by comparison with the experimental data taken at the same facility during 2022 experimental campaign. We propose a novel methodology to consider both, dead-time and pile-up effects simultaneously for these fast detectors and check the applicability to experimental data from 197Au(n, γ), including the saturated 4.9 eV resonance which is an important component of normalization for neutron cross section measurements.
Weathering of outcrops of ultramafic rocks (remnants of ancient oceanic crust) is a source of biologically toxic trace elements, particularly first row transition elements. The Cr and Ni ...concentrations of serpentinite and metabasite outcrops in the northern sector of the Pollino massif (Lucanian Apennines, southern Italy) are hundreds of orders of magnitude higher than those of the upper continental crust. In this region, exposed intermediate to lower crustal rocks are significantly enriched in Ni, Cr, and V relative to the average upper continental crust. We evaluate the levels and distributions of trace elements of environmental concern, including Cr (as total dissolved Cr and Cr(VI)), V, Mn, Fe, Ni, Cu, Zn, As, Pb, and U, in spring waters from the northern sector of the Pollino massif.
The major solutes in the spring waters from this region are Mg-HCO3 and Ca-HCO3. The Mg-HCO3 type waters are produced mainly through the interaction of meteoric waters with serpentinites, whereas the Ca-HCO3 type waters are produced through the interaction of meteoric waters with Ca-rich rocks (i.e., carbonate rocks, calc-schists, and metabasites). Thermodynamic evaluation indicates that in the MgO–SiO2–Al2O3–H2O system, waters flowing in serpentinites fall in the kaolinite field, close to the kaolinite–Mg-vermiculite phase boundary. This result arises because kaolinite is a relatively early reaction product, which is consumed to produce Mg-vermiculite and further Mg-saponite. In the CaO–SiO2–Al2O3–H2O system, Ca-HCO3 type waters fall either in the field of gibbsite or kaolinite, depending on dissolved silica.
Chromium (VI) contamination associated with local mineralogy and with maximum admissible concentration >5μgL−1 was observed for nine springs (both Mg-HCO3 and Ca-HCO3 type waters). The Cr(VI)-rich Ca-HCO3 springs are not located in serpentinites. However, some of these waters likely acquire their high Cr levels from interacting with serpentinite clasts, as in the case of springs flowing through conglomerates. In addition, Cr(VI) contamination is not limited to waters interacting with serpentinites or serpentinite clasts, because in one case weathering of garnet-rich gneiss is responsible for the release of significant amounts of Cr(VI) in solution.
Finally, studies are needed to address the potential health risks associated with the observed high concentrations of Cr(VI) in waters from the Pollino massif area. A mode-of-action analysis is needed to evaluate adverse health risks associated with exposure to Cr(VI) in drinking water, especially as Cr contamination is not limited to springs flowing through serpentinites.
► Serpentinite, metabasite, and garnet-rich gneiss in the Pollino massif, Italy. ► Distributions of Cr(VI) in spring waters. ► Springs waters in the Pollino massif are either Mg-HCO3 or Ca-HCO3. ► Cr(VI) contamination in springs of both Mg-HCO3 and Ca-HCO3 type. ► Contamination is not confined to springs which flow through serpentinites.
Aims
Human Enteroviruses (HEVs) infections have a significant impact on public health, being implicated in outbreaks of meningitis, encephalitis, hand‐foot‐mouth disease and other acute and chronic ...manifestation. In the strategic plan for poliomyelitis eradication, the environmental surveillance of poliovirus (PV) has been identified by the World Health Organization (WHO) as an activity that can complement the surveillance of polio. Having wastewater samples available for PV surveillance allows us to study nonpolio enteroviruses (NPEVs) circulating in the study population, which are widely spread.
Methods and Results
This study was carried out according to the WHO guidelines for environmental surveillance of PV and analysed the circulation of PV and NPEVs through the isolation of viruses in cell cultures in Milan area; from 2006 to 2010, 321 wastewater samples were collected, regularly over time, at the inlet of three diverse waste water treatment plants (WWTPs).
Culturable HEVs were isolated in 80% of sewage samples: all isolates belonged to the HEV‐B group and those circulating more intensely were CVB5 and Echo 6, while CVB4 was the predominant serotype found in 2010. In this study, two type 2 PVs were isolated, both characterized as Sabin like.
Conclusion
Environmental monitoring of HEVs in Milan has proved to be an interesting tool to investigate the circulation and distribution of viruses.
Significance and Impact of the Study
The detection of PV and other NPEV could be predictive of possible re‐emergence of these viruses with an impact on public health. NPEV monitoring could also be a powerful public health tool to investigate the possible role of NPEV in different clinical manifestations.
The radiation used in hadrontherapy treatments interacts with the patient body producing secondary particles, either neutral or charged, that can be used for dose and Bragg peak monitoring and to ...provide a fast feedback on the treatment plans. Recent results obtained from the authors on simplified setups (mono-energetic primary beams interacting with homogeneous tissue-like target) have already indicated the correlation that exists between the flux of these secondaries coming from the target (e.g. protons and photons) and the position of the primary beam Bragg peak. In this paper, the measurements of charged particle fluxes produced by the interaction of a 220 MeV/u carbon ion beam at GSI, Darmstadt, with a polymethyl methacrylate target are reported. The emission region of protons (p), deuterons (d) and tritons (t) has been characterized using a drift chamber while the particle time-of-flight, used to compute the kinetic energy spectra, was measured with a LYSO scintillator. The energy released in the LYSO crystal was used for particle identification purposes. The measurements were repeated with the setup at 60° and 90° with respect to the primary beam direction. The accuracy on the fragments emission profile reconstruction and its relationship with the Bragg peak position have been studied. Based on the acquired experimental evidence, a method to monitor the dose profile and the position of the Bragg peak inside the target is proposed.
The PADME beam line Monte Carlo simulation Bossi, F.; Branchini, P.; Buonomo, B. ...
The journal of high energy physics,
09/2022, Letnik:
2022, Številka:
9
Journal Article
Recenzirano
Odprti dostop
A
bstract
The PADME experiment at the DAΦNE Beam-Test Facility (BTF) of the INFN Laboratory of Frascati is designed to search for invisible decays of dark sector particles produced in ...electron-positron annihilation events with a positron beam and a thin fixed target, by measuring the missing mass of single-photon final states. The presence of backgrounds originating from beam halo particles can significantly reduce the sensitivity of the experiment. To thoroughly understand the origin of the beam background contribution, a detailed G
eant
4-based Monte Carlo simulation has been developed, containing a full description of the detector together with the beam line and its optical elements. This simulation allows the full interactions of each particle to be described, both during beam line transport and during detection, a possibility which represents an innovative way to obtain reliable background predictions.
Aerosol composition and properties variation under the advection of different air masses were investigated, as case studies, by contemporary measurements over the atmospheric column and at the ground ...in a semi-rural site in South Italy. The absence of local strong sources in this area allowed to characterize background aerosol and to compare particle mixing effects under various atmospheric circulation conditions. Aerosol optical depth (AOD) and Ǻngström parameters from radiometric measurements allowed the detection and identification of polluted, dust, and volcanic atmospheric conditions. AODs were the input for a suitable model to evaluate the columnar aerosol composition, according to six main tmospheric components (water-soluble, soot, sea salt accumulation, sea salt coarse, mineral dus,t and biological). Scanning electron microscope (SEM) analysis of particulate sampled with a 13-stage impactor at the ground showed not only fingerprints typical of the different air masses but also the effects of transport and aging on atmospheric particles, suggesting processes that changed their chemical and optical properties. Background columnar aerosol was characterized by 72 % of water-soluble and soot, in agreement with ground-based findings that highlighted 60 % of contribution from anthropogenic carbonate particles and soot. In general, a good agreement between ground-based and columnar results was observed. Under the advection of trans-boundary air masses, water-soluble and soot were always present in columnar aerosol, whereas, in variable percentages, sea salt and mineral particles characterized both dust and volcanic conditions. At the ground, sulfates characterized the amorphous matrix produced in finer stages by the evaporation of solutions of organic and inorganic aerosols. Sulfates were also one of the key players involved in heterogeneous chemical reactions, producing complex secondary aerosol, as such clay-sulfate internally mixed particle externally mixed with soot chains.
Abstract
Lead fluoride (PbF
2
) crystals represent an excellent and
relatively innovative choice for high resolution electromagnetic
calorimeters with high granularity and fast timing for high
...intensity environments. For this reason two PbF
2
crystals, sized
5× 5 × 40 mm
3
, were irradiated with
60
Co
photons up to ∼ 4 Mrad and with 14 MeV neutrons up to a
10
13
n/cm
2
total fluence. Their loss in transmittance was
evaluated at different steps of the photon and neutron irradiation
campaign, resulting in a total of 30% loss above 350 nm. With
crystals always kept in dark conditions, natural and thermal
annealing, as well as optical bleaching with 400 nm light, were
performed on the irradiated specimens, resulting in a partial
recovery of their original optical characteristics.
Sewage surveillance in seven Italian cities between 2005 and 2008, after the introduction of inactivated poliovirus vaccination (IPV) in 2002, showed rare polioviruses, none that were wild-type or ...circulating vaccine-derived poliovirus (cVDPV), and many other enteroviruses among 1,392 samples analyzed. Two of five polioviruses (PV) detected were Sabin-like PV2 and three PV3, based on enzyme-linked immunosorbent assay (ELISA) and PCR results. Neurovirulence-related mutations were found in the 5'noncoding region (5'NCR) of all strains and, for a PV2, also in VP1 region 143 (Ile>Thr). Intertypic recombination in the 3D region was detected in a second PV2 (Sabin 2/Sabin 1) and a PV3 (Sabin 3/Sabin 2). The low mutation rate in VP1 for all PVs suggests limited interhuman virus passages, consistent with efficient polio immunization in Italy. Nonetheless, these findings highlight the risk of wild or Sabin poliovirus reintroduction from abroad. Non-polio enteroviruses (NPEVs) were detected, 448 of which were coxsackievirus B (CVB) and 294 of which were echoviruses (Echo). Fifty-six NPEVs failing serological typing were characterized by sequencing the VP1 region (nucleotides nt 2628 to 2976). A total of 448 CVB and 294 Echo strains were identified; among those strains, CVB2, CVB5, and Echo 11 predominated. Environmental CVB5 and CVB2 strains from this study showed high sequence identity with GenBank global strains. The high similarity between environmental NPEVs and clinical strains from the same areas of Italy and the same periods indicates that environmental strains reflect the viruses circulating in the population and highlights the potential risk of inefficient wastewater treatments. This study confirmed that sewage surveillance can be more sensitive than acute flaccid paralysis (AFP) surveillance in monitoring silent poliovirus circulation in the population as well as the suitability of molecular approaches to enterovirus typing.
PDF
