Full Characterization of the First 1 Inch Industrial Prototype of a New Concept Photodetector

The VSiPMT (Vacuum Silicon PhotoMultiplier Tube) is an original design for an innovative light detector we proposed with the aim to create new scientific instrumentation for industrial applications and physics research. The idea behind this device is to replace the classical dynode chain of a photomultiplier tube with a silicon photomultiplier, the latter acting as an electron detector and amplifier. The VSiPMT offers very attractive features and unprecedented performance, definitely superior to every other photodetector with comparable sensitive surface, such as: negligible power cosumption, excellent photon counting, easy low-voltage-based stabilization and very good time performance. After the feasibility test of the idea, Hamamatsu Photonics realized for our research group two VSiPMT industrial prototypes, that have been fully characterized. The results of the full characterization of the 1-inch industrial prototype are presented in this work.Comment: 11 pages, 14 figure

Recent development on the realization of a 1-inch VSiPMT prototype

The VSiPMT (Vacuum Silicon PhotoMultiplier Tube) is an innovative design for a revolutionary hybrid photodetector. The idea, born with the purpose to use a SiPM for large detection volumes, consists in replacing the classical dynode chain with a SiPM. In this configuration, we match the large sensitive area of a photocathode with the performances of the SiPM technology, which therefore acts like an electron detector and so like a current amplifier. The excellent photon counting capability, fast response, low power consumption and great stability are among the most attractive features of the VSiPMT. In order to realize such a device we first studied the feasibility of this detector both from theoretical and experimental point of view, by implementing a Geant4-based simulation and studying the response of a special non-windowed MPPC by Hamamatsu with an electron beam. Thanks to this result Hamamatsu realized two VSiPMT industrial prototypes with a photocathode of 3mm diameter. We present the progress on the realization of a 1-inch prototype and the preliminary tests we are performing on it

The VSiPMT project

Photon detection is a key factor to study many physical processes in several areas of fundamental physics research. Focusing the attention on photodetectors for particle astrophysics, the future experiments aimed at the study of very high-energy or extremely rare phenomena (e.g. dark matter, proton decay, neutrinos from astrophysical sources) will require additional improvements in linearity, gain, quantum efficiency and single photon counting capability. To meet the requirements of this class of experiments, we propose a new design for a modern hybrid photodetector: the VSiPMT (Vacuum Silicon PhotoMultiplier Tube). The idea is to replace the classical dynode chain of a PMT with a SiPM, which therefore acts as an electron detector and amplifier. The aim is to match the large sensitive area of a photocathode with the performances of the SiPM technology. We now present the preliminary study we are performing to realize a 3-inches VSiPMT prototype

Middle school effects of the Dating Matters (R) comprehensive teen dating violence prevention model on physical violence, bullying, and cyberbullying:A cluster-randomized controlled trial

Few comprehensive primary prevention approaches for youth have been evaluated for effects on multiple types of violence. Dating Matters®: Strategies to Promote Healthy Teen Relationships (Dating Matters) is a comprehensive teen dating violence (TDV) prevention model designed by the Centers for Disease Control and Prevention and evaluated using a longitudinal stratified cluster-randomized controlled trial to determine effectiveness for preventing TDV and promoting healthy relationship behaviors among middle school students. In this study, we examine the prevention effects on secondary outcomes, including victimization and perpetration of physical violence, bullying, and cyberbullying. This study examined the effectiveness of Dating Matters compared to a standard-of-care TDV prevention program in 46 middle schools in four high-risk urban communities across the USA. The analytic sample (N = 3301; 53% female; 50% Black, non-Hispanic; and 31% Hispanic) consisted of 6th–8th grade students who had an opportunity for exposure to Dating Matters in all three grades or the standard-of-care in 8th grade only. Results demonstrated that both male and female students attending schools implementing Dating Matters reported 11% less bullying perpetration and 11% less physical violence perpetration than students in comparison schools. Female Dating Matters students reported 9% less cyberbullying victimization and 10% less cyberbullying perpetration relative to the standard-of-care. When compared to an existing evidence-based intervention for TDV, Dating Matters demonstrated protective effects on physical violence, bullying, and cyberbullying for most groups of students. The Dating Matters comprehensive prevention model holds promise for reducing multiple forms of violence among middle school-aged youth

Effects of the Dating Matters® comprehensive prevention model on health- and delinquency-related risk behaviors in middle school youth:A cluster-randomized controlled trial

Teen dating violence (TDV) is associated with a variety of delinquent behaviors, such as theft, and health- and delinquency-related risk behaviors, including alcohol use, substance abuse, and weapon carrying. These behaviors may co-occur due to shared risk factors. Thus, comprehensive TDV-focused prevention programs may also impact these other risk behaviors. This study examined the effectiveness of CDC's Dating Matters (R): Strategies to Promote Healthy Teen Relationships (Dating Matters) comprehensive TDV prevention model compared to a standard-of-care condition on health- and delinquency-related risk behaviors among middle school students. Students (N = 3301; 53% female; 50% black, non-Hispanic; and 31% Hispanic) in 46 middle schools in four sites across the USA were surveyed twice yearly in 6th, 7th, and 8th grades. A structural equation modeling framework with multiple imputation to account for missing data was utilized. On average over time, students receiving Dating Matters scored 9% lower on a measure of weapon carrying, 9% lower on a measure of alcohol and substance abuse, and 8% lower on a measure of delinquency by the end of middle school than students receiving an evidence-based standard-of-care TDV prevention program. Dating Matters demonstrated protective effects for most groups of students through the end of middle school. These results suggest that this comprehensive model is successful at preventing risk behaviors associated with TDV. clinicaltrials.gov Identifier: NCT01672541

Association of fruits and vegetables consumption and related-vitamins with inflammatory and oxidative stress markers in prediabetic individuals

Abstract\ud \ud Background\ud Dietary guidelines of 5 servings per day of fruits and vegetables (FV) offer a reasonable amount of vitamins to control organic processes, which may contribute to a favorable cardiometabolic profile. This study aimed at investigating whether the intake of the FV group as well as pro-vitamin A carotenoids and vitamins C and E were associated with circulating markers of oxidative stress, inflammation and insulin resistance in Brazilians individuals at cardiometabolic risk.\ud \ud \ud Methods\ud This cross-sectional study included 205 individuals screened for diabetes prevention program in a healthcare center from the School of Public Health, University of São Paulo, conducted in 2008. Possible associations of consumption of FV group, as well as pro-vitamin A carotenoids and vitamins C and E, with circulating markers of oxidative stress (superoxide dismutase – SOD and oxidized LDL – oxLDL), inflammation (C reactive protein, TNF-α and adiponectin) and insulin resistance (HOMA-IR) were investigated. Pearson correlation coefficient, ANOVA and multiple linear regression were employed.\ud \ud \ud Results\ud The sample (64.7% women) had a mean age of 54.1 ± 12.7 years and body mass index of 30.7 ± 5.7 kg/m2. Dietary, physical activity, anthropometric and laboratory data were obtained. Participants consumed a mean of 3.8 servings/day of FV; their FV intake was categorized into three groups: <2.5, 2.5-5.0 and >5.0 servings/day. Significant trends for lower waist circumference (103.4 ± 13.6 vs. 100.1 ± 12.2 vs. 98.2 ± 12.7 cm, p-trend <0.05) and higher adiponectin concentrations (10.4 ± 1.8 vs. 11.9 ± 1.9 vs. 13.6 ± 2.1 ng/mL, p-trend <0.05) were detected across categories. Associations between SOD concentrations (β 0.172 [0.110-0.688]) with FV consumption and between oxLDL concentrations with vitamins C (β -0.333 [−2.568 – -0.218]) and E (β -0.354 [−1.131– -0.110]) intakes, adjusted for age, gender, BMI, saturated fat intake, smoking and physical activity were found. Similar results were observed for the associations between oxLDL and FV intake, but significance disappeared adding adjustment for saturated fat, smoking and physical activity.\ud \ud \ud Conclusion\ud Our data suggest that the intake of FV or selected vitamins may be useful for identifying the oxidative stress and inflammation involved in the genesis of cardiometabolic diseases and for motivating at-risk patients for changing dietary habits.This work was supported by a grant from The São Paulo Foundation for\ud Research Support – FAPESP and from Coordination for Improvement of\ud Graduate Personnel – CAPES (Brazil)

Search for muon-neutrino emission from GeV and TeV gamma-ray flaring blazars using five years of data of the ANTARES telescope

The ANTARES telescope is well-suited for detecting astrophysical transient neutrino sources as it can observe a full hemisphere of the sky at all times with a high duty cycle. The background due to atmospheric particles can be drastically reduced, and the point-source sensitivity improved, by selecting a narrow time window around possible neutrino production periods. Blazars, being radio-loud active galactic nuclei with their jets pointing almost directly towards the observer, are particularly attractive potential neutrino point sources, since they are among the most likely sources of the very high-energy cosmic rays. Neutrinos and gamma rays may be produced in hadronic interactions with the surrounding medium. Moreover, blazars generally show high time variability in their light curves at different wavelengths and on various time scales. This paper presents a time-dependent analysis applied to a selection of flaring gamma-ray blazars observed by the FERMI/LAT experiment and by TeV Cherenkov telescopes using five years of ANTARES data taken from 2008 to 2012. The results are compatible with fluctuations of the background. Upper limits on the neutrino fluence have been produced and compared to the measured gamma-ray spectral energy distribution.Comment: 27 pages, 16 figure

The Antares Collaboration : Contributions to the 34th International Cosmic Ray Conference (ICRC 2015, The Hague)

The ANTARES detector, completed in 2008, is the largest neutrino telescope in the Northern hemisphere. Located at a depth of 2.5 km in the Mediterranean Sea, 40 km off the Toulon shore, its main goal is the search for astrophysical high energy neutrinos. In this paper we collect the 21 contributions of the ANTARES collaboration to the 34th International Cosmic Ray Conference (ICRC 2015). The scientific output is very rich and the contributions included in these proceedings cover the main physics results, ranging from steady point sources, diffuse searches, multi-messenger analyses to exotic physics

All-sky Search for High-Energy Neutrinos from Gravitational Wave Event GW170104 with the ANTARES Neutrino Telescope

Advanced LIGO detected a significant gravitational wave signal (GW170104) originating from the coalescence of two black holes during the second observation run on January 4$^{\textrm{th}}$, 2017. An all-sky high-energy neutrino follow-up search has been made using data from the ANTARES neutrino telescope, including both upgoing and downgoing events in two separate analyses. No neutrino candidates were found within $\pm500$ s around the GW event time nor any time clustering of events over an extended time window of $\pm3$ months. The non-detection is used to constrain isotropic-equivalent high-energy neutrino emission from GW170104 to less than $\sim4\times 10^{54}$ erg for a $E^{-2}$ spectrum