This final article about the CHOOZ experiment presents a complete description of the \(\bar{\nu}_e\) source and detector, the calibration methods and stability checks, the event reconstruction ...procedures and the Monte Carlo simulation. The data analysis, systematic effects and the methods used to reach our conclusions are fully discussed. Some new remarks are presented on the deduction of the confidence limits and on the correct treatment of systematic errors.
We present a field-programmable gate array (FPGA)-based technique for the on-line identification of highly ionizing particles in a liquid xenon (LXe) detector. The method was developed and ...successfully exploited to select <inline-formula> <tex-math notation="LaTeX">\alpha </tex-math></inline-formula> particles emitted by 241 Am sources submerged in LXe in an overwhelming, mostly beam-related, <inline-formula> <tex-math notation="LaTeX">\gamma </tex-math></inline-formula>-ray background. After revising the main features of xenon and other liquid noble gases as ultra-violet (UV) scintillating media, we describe the algorithm idea and its firmware implementation. We then present the results in terms of efficiency and background suppression for the real-time <inline-formula> <tex-math notation="LaTeX">\alpha </tex-math></inline-formula>-particle tagging and the limits of the MEG trigger configuration. Finally, we show that in MEG II we are going to overcome the main issues and further improve the performances.
The electrocatalytic reduction of CO2 into useful fuels, exploiting rationally designed, inexpensive, active, and selective catalysts, produced through easy, quick, and scalable routes, represents a ...promising approach to face today’s climate challenges and energy crisis. This work presents a facile strategy for the preparation of doped SnO2 as an efficient electrocatalyst for the CO2 reduction reaction to formic acid and carbon monoxide. Zn or Ti doping was introduced into a mesoporous SnO2 matrix via wet impregnation and atomic layer deposition. It was found that doping of SnO2 generates an increased amount of oxygen vacancies, which are believed to contribute to the CO2 conversion efficiency, and among others, Zn wet impregnation resulted the most efficient process, as confirmed by X-ray photoelectron spectroscopy analysis. Electrochemical characterization and active surface area evaluation show an increase of availability of surface active sites. In particular, the introduction of Zn elemental doping results in enhanced performance for formic acid formation, in comparison to un-doped SnO2 and other doped SnO2 catalysts. At −0.99 V versus reversible hydrogen electrode, the total faradaic efficiency for CO2 conversion reaches 80%, while the partial current density is 10.3 mA cm−2. These represent a 10% and a threefold increases for faradaic efficiency and current density, respectively, with respect to the reference un-doped sample. The enhancement of these characteristics relates to the improved charge transfer and conductivity with respect to bare SnO2.
The Cylindrical Drift Chamber of the MEG II experiment Chiappini, M.; Baldini, A.M.; Benmansour, H. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
02/2023, Letnik:
1047
Journal Article
Recenzirano
The MEG experiment at the Paul Scherrer Institut (PSI) represents the state of the art in the search for the charged Lepton Flavor Violating μ+→e+γ decay, setting the most stringent upper limit on ...the BR (μ+→e+γ)≤4.2×10−13 (90% C.L.). An upgrade of MEG, MEG II, was designed, commissioned and recently started the physics data taking. Its goal is to reach a sensitivity level of 6×10−14. In order to reconstruct the positron momentum vector a Cylindrical Drift CHamber (CDCH) with unprecedented peculiarities was built, featuring angular and momentum resolutions at the 6.5 mrad and 100 keV/c level. The CDCH is a 2-meter long, 60 cm in diameter, low-mass, single volume detector with high granularity: 9 layers of 192 drift cells, few mm wide, defined by ∼12000 wires in a stereo configuration for longitudinal hit localization. The filling gas mixture is Helium:Isobutane 90:10. The total radiation length is 1.5×10−3 X0, thus minimizing the Multiple Coulomb Scattering and allowing for a single-hit resolution <120μm. After the assembly at INFN Pisa, the CDCH was transported to PSI and integrated into the MEG II experimental apparatus since 2018. The commissioning phase lasted for the past three years until the operational stability was reached in 2020. The analysis software is continuously developing and the tuning of the reconstruction algorithms is one of the main activities. The latest updates on the positron momentum vector resolutions and tracking efficiency are presented.
Investigations of Star Excursion Balance Test (SEBT) performance differences between competition levels and sports are limited and results are inconsistent. The aim of the present study are: 1) to ...compare SEBT performance between elite and semi-professional female volleyball players; 2) to evaluate differences in SEBT scores between positions (Hitters, Middle Blockers, Setters, and Liberoes); and 3) to compare dynamic balance characteristics between professional female Italian volleyball players with NCAA Division I female athletes practicing six different sports (hockey, football, basketball, golf, softball, and volleyball). For the latter comparison, previously published data obtained from a study were used.
Fifty-one female volleyball players were grouped in two groups, elite athletes (EG; N.=27) and semi-professional players (SG; N.=24), and further categorized into hitters, middle blockers, setters, and liberos. Anterior (A), posteromedial (PM), and posterolateral (PL) distances, and composite score (COMP) of SEBT short form were studied. COMP was calculated as the average of the normalized distances across the three directions.
Significant differences were observed for the A (right, P=0.014 and left, P=0.011), PL (right, P=0.017 and left, P=0.008), PM (P<0.001) directions, and COMP scores (right, P=0.008 and left, P=0.009), with higher normalized distances noted for the EG and no differences between different positions. COMP scores were lower for the EG than the NCAA Division I female hockey (P<0.001) and football players (P=0.031) but similar to those of basketball, golf, softball, and volleyball players.
The EG scored higher on dynamic postural-control tasks than the SG. SEBT performance varied significantly between sports. Clinicians and strength coaches need to be aware of sport specific differences in dynamic postural control measurements in both rehabilitation and athletic development.
We report on a simple electrochemical system able to capture gaseous carbon dioxide from a gas mixture and convert it into syngas. The capture/release module is implemented via regeneration of NaOH ...and acidification of NaHCO3 inside a four-chamber electrochemical flow cell employing Pt foils as catalysts, while the conversion is carried out by a coupled reactor that performs electrochemical reduction of carbon dioxide using ZnO as a catalyst and KHCO3 as an electrolyte. The capture module is optimized such that, powered by a current density of 100 mA/cm2, from a mixture of the CO2–N2 gas stream, a pure and stable CO2 outlet flow of 4–5 mL/min is obtained. The conversion module is able to convert the carbon dioxide into a mixture of gaseous CO and H2 (syngas) with a selectivity for the carbon monoxide of 56%. This represents the first all-electrochemical system for carbon dioxide capture and conversion.
Abstract
Background: Whenever oral treatment or botulinum toxin injections fail to control severe spasticity, a trial with intrathecal baclofen is recommended no earlier than 1 year after brain ...injury. When irreversible contractures are to be avoided, such a trial might be done earlier. Some have briefly reported cognitive modifications with this treatment.
Methods: During the trial period, intrathecal baclofen is continuously infused by a portable external pump through an intrathecal catheter. The daily dose is adjusted according to the clinical response. If the expected response is obtained by reduction of spasticity, a programmable pump is then implanted. Throughout the procedure, close neuropsychological follow-up is pursued.
Results: Two persons with extremely severe brain injury and spasticity received a programmable pump less than 10 months after trauma. Unexpectedly, one emerged from the minimally conscious state and the other from post-traumatic amnesia.
Conclusions: Intrathecal baclofen should be considered within the first year after brain injury whenever spasticity does not respond to medication. ITB lessens the degree of spasticity which in turn facilitates care and, thus, has the potential to limit contractures. After severe brain injury, this treatment might trigger recovery from altered states of consciousness, improve cognition and facilitate rehabilitation.
Carbon monoxide (CO) and formic acid (HCOOH) are suggested to be the most convenient products from electrochemical reduction of CO
2
according to techno-economic analysis. To date, tremendous ...advances have been achieved in the development of catalysts and processes, which make this research topic even more interesting to both academic and industrial sectors. In this work, we report nanostructured Cu-Al materials that are able to convert CO
2
to CO and HCOOH with good efficiency. The catalysts are synthesized
via
a green microwave-assisted solvothermal route, and are composed of Cu
2
O crystals modified by Al. In KHCO
3
electrolyte, these catalysts can selectively convert CO
2
to HCOOH and syngas with H
2
/CO ratios between 1 and 2 approaching one unit faradaic efficiency in a wide potential range. Good current densities of 67 and 130 mA cm
−2
are obtained at −1.0 V and −1.3 V vs. reversible hydrogen electrode (RHE), respectively. When switching the electrolyte to KOH, a significant selectivity up to 20% is observed for C
2
H
4
formation, and the current densities achieve 146 and 222 mA cm
−2
at −1.0 V and −1.3 V vs. RHE, respectively. Hence, the choice of electrolyte is critically important as that of catalyst in order to obtain targeted products at industrially relevant current densities.
The Timing Counter of the MEG (Mu to Electron Gamma) experiment is designed to deliver trigger information and to accurately measure the timing of the in searching for the decay . It is part of a ...magnetic spectrometer with the decay target in the center. It consists of two sectors upstream and downstream the target, each one with two layers: the inner one made with scintillating fibers read out by APDs for trigger and track reconstruction, the outer one consisting in scintillating bars read out by PMTs for trigger and time measurement. The design criteria, the obtained performances and the commissioning of the detector are presented herein.
We present new results based on the entire CHOOZ (The CHOOZ experiment is named after the new nuclear power station operated by Électricité de France (EdF) near the village of Chooz in the Ardennes ...region of France) data sample. We find (at 90% confidence level) no evidence for neutrino oscillations in the
ν
̄
e
disappearance mode, for the parameter region given by approximately
δm
2>7·10
−4
eV
2
for maximum mixing, and sin
22
θ=0.10 for large
δm
2. Lower sensitivity results, based only on the comparison of the positron spectra from the two different-distance nuclear reactors, are also presented; these are independent of the absolute normalization of the
ν
̄
e
flux, the cross section, the number of target protons and the detector efficiencies.
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