Detection of the Diffuse Supernova Neutrino Background with JUNO

As an underground multi-purpose neutrino detector with 20 kton liquid scintillator, Jiangmen Underground Neutrino Observatory (JUNO) is competitive with and complementary to the water-Cherenkov detectors on the search for the diffuse supernova neutrino background (DSNB). Typical supernova models predict 2-4 events per year within the optimal observation window in the JUNO detector. The dominant background is from the neutral-current (NC) interaction of atmospheric neutrinos with 12C nuclei, which surpasses the DSNB by more than one order of magnitude. We evaluated the systematic uncertainty of NC background from the spread of a variety of data-driven models and further developed a method to determine NC background within 15\% with {\it{in}} {\it{situ}} measurements after ten years of running. Besides, the NC-like backgrounds can be effectively suppressed by the intrinsic pulse-shape discrimination (PSD) capabilities of liquid scintillators. In this talk, I will present in detail the improvements on NC background uncertainty evaluation, PSD discriminator development, and finally, the potential of DSNB sensitivity in JUNO

Performances de l'électronique front-end du système des PMTs 3” dans l'expérience JUNO et étude de son impact sur les mesures de charge et de temps.

The observation of neutrino oscillations has led to questioning the Standard Model of particle physics, and precisely measuring the neutrino oscillation parameters and answering the question about the ordering of the neutrino mass states could provide the key to understanding other unsolved puzzles in both cosmology and particle physics. This is the objective of the Jiangmen Underground Neutrino Observatory (JUNO), a multi-purpose neutrino experiment expected to start taking data in 2024, which will detect reactor anti-neutrinos from two nearby nuclear power plants using a central detector containing 20 kton of liquid scintillator. The emitted photons will be observed by two large arrays of 20-inch (LPMTs) and 3-inch (SPMTs) photomultiplier tubes, the SPMT system having been designed to serve as a complementary array of photodetectors to the LPMT system. By mostly operating in a photon-counting mode, it will help calibrate the energy response of the LPMTs as well as help better understand the systematics of the system. Located underwater, its read out electronics consists in 128 SPMTs being connected to a single ABC front-end board hosting 8 16-channels CATIROC ASICs. Precise studies on the performances of this ABC board are presented in this thesis, including studies on pedestal measurements (0.05 photoelectron pedestalwidths), charge linearity and calibration (0.05% deviation to linear model), time resolution (about 0.25 ns),crosstalk (below 0.15%), as well as on test-benches combining all the SPMT electronics to date. The boards’ability to asynchronously auto-trigger on random SPE events with thresholds as low as 1/3 photoelectronis also demonstrated, and the processing of a PMT signal within the ABC board is studied with precise parametrizations of certain CATIROC ASIC features such as the trigger time and time walk, the deadtimesand the charge acceptance. This intricate knowledge of the SPMT electronics was additionally implemented in the JUNO simulation, and simulated events showed that the impact of the response of the SPMT system on physical studies involving the charge and time information was negligible before the response of the PMTs. This work has furthermore led to the qualification of the performances of the 25,600 SPMTs and of the 220 ABC front-end boards, which will pave the way for the exploitation of the JUNO physics data starting from 2024.L’observation du phénomène d’oscillation des neutrinos a conduit à la remise en question du Modèle Standard de la physique des particules. Effectuer une mesure précise de leurs paramètres d’oscillation, ainsi que répondre à la question de la hiérarchie de leurs états de masse, pourrait bien fournir des éléments de réponse quant à d’autres énigmes non résolues en cosmologie et en physique des particules.C’est l’objectif de l’observatoire souterrain de neutrinos de Jiangmen (JUNO), une expérience polyvalente sur les neutrinos devant commencer à prendre des données en 2024, qui détectera les anti-neutrinos de réacteurs de deux centrales nucléaires voisines à l’aide d’un détecteur central contenant 20000 tonnes de scintillateur liquide. Les photons émis seront observés par deux grands réseaux de tubes photomultiplicateursde 20 pouces (LPMTs) et de 3 pouces (SPMTs), le système SPMT ayant été conçu pour servir de réseau complémentaire au système LPMT. Fonctionnant principalement dans un mode de comptage de photons, il permettra d’étalonner la réponse en énergie des LPMTs et de mieux comprendre les erreurs systématiques du système. Entreposée dans de l’eau, son électronique de lecture consiste en 128 SPMTs connectés à une même carte frontale ABC, hébergeant 8 ASICs CATIROC de 16 voies. Des études précises menées sur les performances de cette carte ABC sont présentées dans cette thèse, comprenant des études sur les mesures de piédestaux (largeurs inférieures à 0,05 photoélectron), la linéarité et l’étalonnage en charge (déviation de 0,05% par rapport à un modèle linéaire), la résolution temporelle (environ 0,25 ns), la diaphonie (inférieure à 0,15%), ainsi que sur des bancs de tests combinant toute l’électronique du système SPMT à ce jour. La bonne capacité des cartes ABC à déclencher de manière asynchrone et aléatoire sur des photoélectrons avec des seuils à 1/3 de photoélectron est également démontrée, et le traitement d’un signal PM dans la carte ABC est étudié avec le paramétrage précis de certaines caractéristiques des ASICs CATIROC telles que le temps de déclenchement et le time walk, les temps morts et l’ acceptance en charge.Cette connaissance approfondie de l’électronique SPMT a également été implémentée dans la simulation JUNO et les événements simulés ont montré que l’impact de la réponse du système SPMT sur des études physiques impliquant les informations de charge et de temps est négligeable devant la réponse des PMs. Ces travaux ont en outre abouti à la qualification des performances des 25600 SPMTs et des 220 cartes frontales ABC, ce qui ouvre la voie à l’exploitation des données de physique de JUNO à partir de 2024

Performances de l'électronique front-end du système des PMTs 3” dans l'expérience JUNO et étude de son impact sur les mesures de charge et de temps.

The observation of neutrino oscillations has led to questioning the Standard Model of particle physics, and precisely measuring the neutrino oscillation parameters and answering the question about the ordering of the neutrino mass states could provide the key to understanding other unsolved puzzles in both cosmology and particle physics. This is the objective of the Jiangmen Underground Neutrino Observatory (JUNO), a multi-purpose neutrino experiment expected to start taking data in 2024, which will detect reactor anti-neutrinos from two nearby nuclear power plants using a central detector containing 20 kton of liquid scintillator. The emitted photons will be observed by two large arrays of 20-inch (LPMTs) and 3-inch (SPMTs) photomultiplier tubes, the SPMT system having been designed to serve as a complementary array of photodetectors to the LPMT system. By mostly operating in a photon-counting mode, it will help calibrate the energy response of the LPMTs as well as help better understand the systematics of the system. Located underwater, its read out electronics consists in 128 SPMTs being connected to a single ABC front-end board hosting 8 16-channels CATIROC ASICs. Precise studies on the performances of this ABC board are presented in this thesis, including studies on pedestal measurements (0.05 photoelectron pedestalwidths), charge linearity and calibration (0.05% deviation to linear model), time resolution (about 0.25 ns),crosstalk (below 0.15%), as well as on test-benches combining all the SPMT electronics to date. The boards’ability to asynchronously auto-trigger on random SPE events with thresholds as low as 1/3 photoelectronis also demonstrated, and the processing of a PMT signal within the ABC board is studied with precise parametrizations of certain CATIROC ASIC features such as the trigger time and time walk, the deadtimesand the charge acceptance. This intricate knowledge of the SPMT electronics was additionally implemented in the JUNO simulation, and simulated events showed that the impact of the response of the SPMT system on physical studies involving the charge and time information was negligible before the response of the PMTs. This work has furthermore led to the qualification of the performances of the 25,600 SPMTs and of the 220 ABC front-end boards, which will pave the way for the exploitation of the JUNO physics data starting from 2024.L’observation du phénomène d’oscillation des neutrinos a conduit à la remise en question du Modèle Standard de la physique des particules. Effectuer une mesure précise de leurs paramètres d’oscillation, ainsi que répondre à la question de la hiérarchie de leurs états de masse, pourrait bien fournir des éléments de réponse quant à d’autres énigmes non résolues en cosmologie et en physique des particules.C’est l’objectif de l’observatoire souterrain de neutrinos de Jiangmen (JUNO), une expérience polyvalente sur les neutrinos devant commencer à prendre des données en 2024, qui détectera les anti-neutrinos de réacteurs de deux centrales nucléaires voisines à l’aide d’un détecteur central contenant 20000 tonnes de scintillateur liquide. Les photons émis seront observés par deux grands réseaux de tubes photomultiplicateursde 20 pouces (LPMTs) et de 3 pouces (SPMTs), le système SPMT ayant été conçu pour servir de réseau complémentaire au système LPMT. Fonctionnant principalement dans un mode de comptage de photons, il permettra d’étalonner la réponse en énergie des LPMTs et de mieux comprendre les erreurs systématiques du système. Entreposée dans de l’eau, son électronique de lecture consiste en 128 SPMTs connectés à une même carte frontale ABC, hébergeant 8 ASICs CATIROC de 16 voies. Des études précises menées sur les performances de cette carte ABC sont présentées dans cette thèse, comprenant des études sur les mesures de piédestaux (largeurs inférieures à 0,05 photoélectron), la linéarité et l’étalonnage en charge (déviation de 0,05% par rapport à un modèle linéaire), la résolution temporelle (environ 0,25 ns), la diaphonie (inférieure à 0,15%), ainsi que sur des bancs de tests combinant toute l’électronique du système SPMT à ce jour. La bonne capacité des cartes ABC à déclencher de manière asynchrone et aléatoire sur des photoélectrons avec des seuils à 1/3 de photoélectron est également démontrée, et le traitement d’un signal PM dans la carte ABC est étudié avec le paramétrage précis de certaines caractéristiques des ASICs CATIROC telles que le temps de déclenchement et le time walk, les temps morts et l’ acceptance en charge.Cette connaissance approfondie de l’électronique SPMT a également été implémentée dans la simulation JUNO et les événements simulés ont montré que l’impact de la réponse du système SPMT sur des études physiques impliquant les informations de charge et de temps est négligeable devant la réponse des PMs. Ces travaux ont en outre abouti à la qualification des performances des 25600 SPMTs et des 220 cartes frontales ABC, ce qui ouvre la voie à l’exploitation des données de physique de JUNO à partir de 2024

Sexual communication in the termite Prorhinotermes simplex (Isoptera, Rhinotermitidae) mediated by a pheromone from female tergal glands

We studied the post-flight behavior and sex attraction in imagoes of the termite Prorhinotermes simplex (Rhinotermitidae, Prorhinotermitinae). Pairing is mediated by the secretion from tergal glands, exposed by females in a calling posture and highly attractive to males. Analysis of extracts of these glands by means of gas chromatography with electroantennographic detection indicated a chromatographic area corresponding to an intense physiological response of males. The retention characteristics of this area proved to be identical with those of (3Z,6Z,8E)-dodeca-3,6,8-trien-1-ol. Electroantennographic and behavioral assays revealed that units of picograms of the compound represent a stimulus qualitatively and quantitatively equivalent to one female tergal gland. Thus, we hypothesize that (3Z,6Z,8E)-dodeca-3,6,8-trien-1-ol is a major component of the female sex pheromone in P. simplex. © 2009 Birkhäuser Verlag, Basel/Switzerland.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

CATIROC: an integrated chip for neutrino experiments using photomultiplier tubes

An ASIC (Application Specific Integrated Chip) named CATIROC (Charge And Time Integrated Read Out Chip) has been developed for the next-generation neutrino experiments using a large number of photomultiplier tubes (PMTs). Each CATIROC provides the time and the charge measurements for 16 configurable input channels operating in auto-trigger mode. Originally designed for the light emission in water Cherenkov detectors, we show in this paper that its use can be extended to liquid-scintillator based experiments. The ∼ 26000 3-inch PMTs of the JUNO experiment, under construction in China, is a case in point. This paper describes the features of CATIROC with a special attention to the most critical points for its application to the time profile of the light emission in liquid scintillators. The achieved performances in both charge and time measurements can be inputs for future high-precision experiments making use of PMTs or other photo-sensitive detectors

PHEROMONES and EXOCRINE GLANDS IN ISOPTERA

Termites are eusocial insects that have a peculiar and intriguing system of communication using pheromones. The termite pheromones are composed of a blend of chemical substances and they coordinate different social interactions or activities, including foraging, building, mating, defense, and nestmate recognition. Some of these sociochemicals are volatile, spreading in the air, and others are contact pheromones, which are transmitted by trophallaxis and grooming. Among the termite semiochemicals, the most known are alarm, trail, sex pheromones, and hydrocarbons responsible for the recognition of nestmates. The sources of the pheromones are exocrine glands located all over the termite body. The principal exocrine structures considered pheromone-producing glands in Isoptera are the frontal, mandibular, salivary or labial, sternal, and tergal glands. The frontal gland is the source of alarm pheromone and defensive chemicals, but the mandibular secretions have been little studied and their function is not well established in Isoptera. The secretion of salivary glands involves numerous chemical compounds, some of them without pheromonal function. The worker saliva contains a phagostimulating pheromone and probably a building pheromone, while the salivary reservoir of some soldiers contains defensive chemicals. The sternal gland is the only source of trail-following pheromone, whereas sex pheromones are secreted by two glandular sources, the sternal and tergal glands. To date, the termite semiochemicals have indicated that few molecules are involved in their chemical communication, that is, the same compound may be secreted by different glands, different castes and species, and for different functions, depending on the concentration. In addition to the pheromonal parsimony, recent studies also indicate the occurrence of a synergic effect among the compounds involved in the chemical communication of Isoptera. (C) 2010 Elsevier B.V

Beyond cuticular hydrocarbons: evidence of proteinaceous secretion specific to termite kings and queens

In 1959, P. Karlson and M. Lüscher introduced the term ‘pheromone’, broadly used nowadays for various chemicals involved in intraspecific communication. To demonstrate the term, they depicted the situation in termite societies, where king and queen inhibit the reproduction of nest-mates by an unknown chemical substance. Paradoxically, half a century later, neither the source nor the chemical identity of this ‘royal’ pheromone is known. In this study, we report for the first time the secretion of polar compounds of proteinaceous origin by functional reproductives in three termite species, Prorhinotermes simplex, Reticulitermes santonensis and Kalotermes flavicollis. Aqueous washes of functional reproductives contained sex-specific proteinaceous compounds, virtually absent in non-reproducing stages. Moreover, the presence of these compounds was clearly correlated with the age of reproductives and their reproductive status. We discuss the putative function of these substances in termite caste recognition and regulation

(E,E)-α-farnesene, an alarm pheromone of the termite Prorhinotermes canalifrons

SCOPUS: ar.jinfo:eu-repo/semantics/publishe