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Hugon, Christophe. "Analyse des données de l’expérience NEMO3 pour la recherche de la désintégration double bêta sans émission de neutrinos. Étude des biais systématiques du calorimètre et développements d’outils d’analyse". Thesis, Paris 11, 2012. http://www.theses.fr/2012PA112335/document.
Pełny tekst źródłaThe NEMO3 experiment was researching the ββ0ν decay by using various sources of double beta decay isotopes (mainly ¹ººMo, ⁸²Se, ¹¹⁶Cd and ¹³⁰Te for about 10 kg in total). The detector was located in the “Laboratoire Souterrain de Modane”, in the halfway point of the Frejus tunnel. This experiment demonstrated that the "tracko-calo" technology is really competitive and, in addition, it gives new results for the ββ2ν and the ββ0ν decay research. Moreover it opened a new way for its successor SuperNEMO, which aim is to reach a mass of 100 kg of ⁸²Se (for a sensitivity of 10²⁶ years). The main goal of the thesis is to measure the ββ2ν and ββ0ν decay of the ¹ººMo to the excited state 0₁⁺ of the ¹ººRu thanks to the whole NEMO3 data, with new original methods of analysis and through the development of the collaboration analysis software. The results obtained for the ground states (gs) and excited states ββ2ν of the ¹ººMo are T1/2(ββ2ν,gs)=(7,05±0,01(stat)±0,54(syst)).10¹⁸ years and T1/2(ββ2ν, 0₁⁺)=(6,15±1,1(stat)±0,78)).10²º years. Those results are compatibles with the last published ones by the collaboration. For the ββ0ν(0₁⁺), this work gave a half-life time of T1/2 (ββ0ν, 0₁⁺)>2,6.10²³ years, improving significantly the last published results. Furthermore those methods also allowed to present a new and more exhaustive background noise model for this experiment. The second point of this work was to measure the systematics errors of the NEMO3 calorimeter, among others, due to the wavelength of the NEMO3 calibration systems. This work was done using a new test bench based on LED. This bench also allowed to contribute to the development of the SuperNEMO calorimeter, especially in the time characteristic and the energy linearity measurement of the PMT intended to the demonstrator of the experiments
Armatol, Antoine. "Innovative methods for background rejection in next-generation neutrinoless double beta decay bolometric experiments". Electronic Thesis or Diss., université Paris-Saclay, 2023. http://www.theses.fr/2023UPASP105.
Pełny tekst źródłaThe search for neutrinoless double beta decay (0ν2β) is a major challenge in contemporary physics, as its observation would demonstrate that the neutrino is a Majorana particle. The half-life of the process being related to the effective Majorana mass mββ, it would also provide a measure of the neutrino mass scale and information on its mass hierarchy. The next-generation experiment CUPID aims to reach a sensitivity high enough to explore completely the region of possible values for mββ in the case of the inverted hierarchy. It will use scintillating bolometers made of a Li₂MoO₄ (LMO) crystal, containing ¹⁰⁰Mo as the 2β candidate isotope, coupled to a Ge bolometric light detector. Thanks to the dual light/heat readout, CUPID will be able to reject the background due to α particles, which is the main source limiting the sensitivity of CUORE, its predecessor, and aims to achieve a background level of 10⁻⁴ counts/kg/keV/year (ckky) in the region of interest (ROI). However, if the 0ν2β still eludes us after CUPID, we will have to push the background reduction even further to explore the spectrum of values for mββ possible in the case of the normal mass hierarchy. It is in this context that BINGO (Bi-Isotope 0ν2β Next Generation Observatory) and the work of this thesis lay. This project aims to test innovative methods for achieving a background of 10⁻⁵ ckky in the ROI of ¹⁰⁰Mo but also of ¹³⁰Te, respectively embedded in LMO and TeO₂ crystals. Firstly, an innovative assembly of bolometers reducing the amount of passive material around the detectors has been developed and validated. Secondly, R&D on implementing a cryogenic active veto composed of scintillators around the volume containing the bolometers was done to reject external γ events by coincidence. A study of potential candidates led to the selection of the BGO for the material. A cryogenic test of a prototype veto module containing two BGOs is also reported in this thesis. Other light collection measurements have also been done at room temperature. Finally, to use TeO₂ crystals as scintillating bolometers, it is necessary to boost the performance of the light detectors. To achieve this goal, BINGO will operate light detectors using the Neganov-Trofimov-Luke (NTL) effect to amplify the signal. An R&D campaign has been conducted to test a new method for depositing aluminum electrodes and different electrode geometries
Oliviero, Guillaume. "Expérience SuperNEMO pour la recherche de la double désintégration bêta sans émission de neutrino : conception et réalisation du système de déclenchement du module démonstrateur". Thesis, Normandie, 2018. http://www.theses.fr/2018NORMC236/document.
Pełny tekst źródłaThe SuperNEMO experiment is designed for the neutrinoless double beta decay (ββ) research involving a massive Majorana neutrino (ν ≡ ν̄). The demonstrator module of the experiment is currently being installed at the Laboratoire Souterrain de Modane (LSM). The so-called tracko-calo detection technique allows the energy measurement of the particles passing through the detector and a complete reconstruction of their kinematics.This thesis presents the design, simulation and implementation of the electronics trigger system for the SuperNEMO demonstrator module. The purpose of this system is to maximize the detection efficiency for ββ events as well as for background events due to natural radioactivity while reducing the acquisition rate caused by spurious events. Pattern recognition and calorimeter-tracker association algorithms have been developed and implemented in electronic boards after validation by Monte-Carlo simulations. The performance targets have been reached, taking into account different constraints (physics of the detectors, electronics, real time) with maximized detection efficiency for events of interest
Soulé, Benjamin. "Recherche des désintégrations double bêta avec et sans émission de neutrinos du 82Se vers les états excités du 82Kr dans l'expérience NEMO3 : développement de dispositifs de mesure ultra-sensibles d'émanation du Radon pour l'expérience SuperNEMO". Thesis, Bordeaux, 2015. http://www.theses.fr/2015BORD0198/document.
Pełny tekst źródłaThe NEMO3 detector was installed in the Laboratoire Souterrain de Modane, in 2003, in orderto search for neutrinoless double beta decay (ββ0v). The specificity of this experiment was the possibility to study several isotopes simultaneously. Among them were 100Mo, 82Se, 96Zr or 150Nd. In addition to setting the best limits on these isotopes half-lives for theββ 0v process, the detector performed precise measurements of their 2v ββdecays. The first point of this work was to measure the half-lives of 2v ββand 0v ββdecays of 82Se to the 0+2 excited state of 82Kr using NEMO3 data. Since those processes have not been observed, only limits were set. The resulting half-life limits are T2 1=2(82Se; 0+1 → 0+2) > 1:29 x 1021 yr and T01=2(82Se; 0+1 → 0+2) > 2:31 x 1022 yr. The latest is the first limit ever measured for this decay. SuperNEMO is the successor to NEMO3 and will aim to reach an half-life sensitivity of 1026 yr for the 0v ββdecay of 82Se. Radon being a source of background for the search of this decay, its concentration inside the detector must be less than 0:15 mBq.m-3. To reach this objective, Radon emanation from the detector componants has to be checked. The second goal of this thesis was thus to develop two setups able to measure Radon emanation. Those two devices, each consisting of an emanation chamber associated to an electrostatic detector, were calibrated before their backgrounds were characterized. With a sensitivity of a few mBq.m-3, these setups measured the Radon emanation rate of several materials which will be used for the construction of the SuperNEMO detector
Etienvre, Anne-Isabelle. "Méthode d'analyse pour la recherche de la double désintégration bêta sans émission de neutrinos dans l'expérience NEMO3. Etude du bruit de fond et premiers résultats". Phd thesis, Université Paris Sud - Paris XI, 2003. http://tel.archives-ouvertes.fr/tel-00002824.
Pełny tekst źródłaHugon, Christophe. "Analyse des données de l'expérience NEMO3 pour la recherche de la désintégration double bêta sans émission de neutrinos. Étude des biais systématiques du calorimètre et développements d'outils d'analyse". Phd thesis, Université Paris Sud - Paris XI, 2012. http://tel.archives-ouvertes.fr/tel-00796403.
Pełny tekst źródłaMacko, Miroslav. "Expérience SuperNEMO : Études des incertitudes systématiques sur la reconstruction de traces et sur l'étalonnage en énergie. Evaluation de la sensibilité de la 0nbb avec émission de Majoron pour le Se-82". Thesis, Bordeaux, 2018. http://www.theses.fr/2018BORD0368/document.
Pełny tekst źródłaPresented thesis is composed of variety of projects which I performed within theconstruction phase of SuperNEMO demonstrator during the period 2015-2018.SuperNEMO experiment, located at underground laboratory LSM, is designed to searchfor 0nbb of 82Se. Its technology, which takes advantage of particle tracking, is unique inthe field of double beta decay experiments. Event topology reconstruction is powerful toolfor suppression of naturally-occurring background radiation.Part of the thesis is dedicated to experimental work. I took part in assembly and testingof optical modules - the integral part of SuperNEMO calorimeter. Results of tests afterassembly of 520 optical modules are presented in the thesis. Furthermore, I present resultsof complete mapping of 207Bi sources performed using pixel detectors. I also present precisemeasurements of their activities for which I used HPGe detectors. These 207Bi sources willbe used for calibration of the calorimeter. Study played a key role in choice of 42 sourceswhich were installed in the demonstrator and will take part in calibration of the demonstrator.Another part of the thesis contains projects focused on Monte Carlo simulations. In firstof them, I studied a vertex reconstruction precision achievable by reconstruction algorithmdeveloped for SuperNEMO experiment. Precision is evaluated using different statisticalmethods in variety of different conditions (magnetic field, energy of electrons, angles ofemission, etc.). Factors influencing the precision, based on the achieved results are discussed.In 2018, I also performed simulations of neutron shielding. Variety of shielding materialswith different thicknesses were (in the simulation) exposed to realistic neutron spectrumfrom LSM and the fluxes behind the shielding were estimated. It was shown that the partsof the detector made of Iron should be expected to capture vast majority of neutrons passingthe shielding. I also discuss a problem with simulation of deexcitation gamma radiation,emitted after thermal neutron capture, which arises in standard software packages. I proposednew extended generator capable to resolve the problem and demonstrate the conceptin analytically solvable example.Along with standard 0nbb, SuperNEMO will be capable of searching for more exoticmodes of the decay. In the thesis, I present possible half-life limits achievable by SuperNEMOfor 0nbb with emission of one or two Majorons. The study is performed asa function of activity of internal contamination from 208Tl and 214Bi isotopes. Measurementperiod after which SuperNEMO should be able to improve half-life limits of NEMO-3 (incase the decay would not be observed) are estimated
Predkladaná dizertaˇcná práca je zložená z projektov rôzneho charakteru, na ktorýchsom pracoval vo fáze výstavby SuperNEMO demonštrátora v období rokov 2015-2018.Experiment SuperNEMO, umiestnený v podzemnom laboratóriu LSM, je zameraný nahl’adanie 0nbb v 82Se. Experiment je založený na technológii rekonštrukcie dráh elektrónovvznikajúcich v rozpade. Tento prístup je jedineˇcný v oblasti 0nbb experimentov.Rekonštrukcia topológie udalostí je silným nástrojom na potlaˇcenie pozad’ovej aktivity vyskytujúcejsa v laboratóriu, ako aj v konštrukˇcných materiáloch detektora.Cˇ ast’ práce je venovaná experimentálnym úlohám. Zúcˇastnil som sa na konštrukciioptických modulov - súˇcasti hlavného kalorimetra. Práca obsahuje výsledky prípravy atestovania 520 optických modulov, a takisto výsledky kompletného mapovania kalibraˇcných207Bi zdrojov vykonaného za pomoci pixelových detektorov. V tejto ˇcasti sú odprezentovanéaj výsledky merania ich aktivít za pomoci HPGe detektorov. Štúdia zohrávala kl’úˇcovúúlohu pri výbere 42 zdrojov, ktoré boli nainštalované do prvého SuperNEMO modulu, dodemonštrátora, a budú použité na jeho energetickú kalibráciu.ˇ Dalšiu ˇcast’ práce tvoria úlohy zamerané na Monte Carlo simulácie. Prvým z nich,je štúdia presnosti rekonštrukcie vertexu dvojitého beta rozpadu. Rozpadové vertexy súrekonštruované tzv. CAT (Cellular Automaton Tracker) algoritmom vyvinutým pre experimentSuperNEMO. V štúdii sú porovnávané viaceré spôsoby definovania presnosti rekonštrukcie.Presnost’ je skúmaná v závislosti na magnetickom poli v detektore, energii elektrónov,uhlov ich emisie atd’. Na základe výsledkov sú v štúdii pomenované faktory, ktoré ovplyvˇnujú presnost’ rekonštrukcie vertexov dvojitého beta rozpadu.V roku 2018 som takisto vypracoval štúdie neutrónového tienenia. Oˇcakávané toky neutrónovza tienením boli odhadnuté pomocou Monte Carlo simulácie. Kvalita odtienenia neutrónovz realistickéh pozad’ového spektra, nameraného v LSM, bola skúmana pre tri rôznemateriály rôznych hrúbok. Výsledky ukázali, že neutrónový tok prechádzajúci tienenímbude primárne zachytávaný na komponentoch detektora zhotoveného zo železa. V rámcištúdie neutrónového tienenia je takisto diskutovaný problém simulácie deexcitaˇcných gamakaskád, produkovaných jadrami, po záchyte termálnych neutrónov. Štandardné simulaˇcnésoftvérové balíˇcky využívajú generátory gama kaskád nepostaˇcujúce pre potreby štúdie.Navrhol som nový generátor, ktorý je schopný tieto problémy vyriešit’. Funkˇcnost’ generátorabola preukázaná na príklade jednoduchého systému.Okrem štandardného 0nbb je SuperNEMO experiment schopný hl’adat’ aj jeho exotickejšieverzie. V práci sa nachádzajú odhady limitov ˇcasu polpremeny 0nbb s emisiou jednéhoalebo dvoch Majorónov, dosiahnutel’né SuperNEMO demonštrátorom. Tieto limity sú študovanév závislosti na aktivite izotopov 208Tl a 214Bi, ktoré kontaminujú zdrojovú 82Se fóliu.Bola odhadnuá doba merania, za ktorú bude SuperNEMO schopný vylepšit’ limity ˇcasu polpremeny,pre dva spomenuté rozpadové módy, dosiahnutých experimentom NEMO-3
Jollet, Cécile. "Expérience NEMO3 : Étude de la stabilité des étalonnages en énergie et en temps du calorimètre : Mesure de la contribution des neutrons au bruit de fond de la double désintégration bêta sans émission de neutrino". Bordeaux 1, 2002. http://www.theses.fr/2002BOR12551.
Pełny tekst źródłaEtienvre, Anne-Isabelle. "Méthode d'analyse pour la recherche de la double désintégration bêta sans émission de neutrinos dans l'expérience NEMO3 : étude du bruit de fond et premiers résultats". Paris 11, 2003. http://www.theses.fr/2003PA112026.
Pełny tekst źródłaThe NEMO3 detector, installed in the Fréjus Underground Laboratory, is dedicated to the study of neutrinoless double beta decay : the observation of this process would sign the massive and Majorana nature of neutrino. The experiment consists in very thin central source foils (the total mass is equal to 10 kg), a tracking detector made of drift cells operating in Geiger mode, a calorimeter made of plastic scintillators associated to photomultipliers, a coil producing a 30 gauss magnetic field and two shields, dedicated to the reduction of the γ-ray and neutron fluxes. In the first part, I describe the implications of several mechanisms, related to trilinear R-parity violation, on ββ0v. The second part is dedicated to a detailed study of the tracking detector of the experiment : after a description of the different working tests, I present the determination of the characteristics of the tracking reconstruction (transverse and longitudinal resolution, by Geiger cell and precision on vertex determination, charge recognition). A last part corresponds to the analysis of the data taken by the experiment. On the one hand, an upper limit on the 208-Tl activity of the sources has been determined : it is lower than 68 mBq/kg, at 90% of convidence level. On the other hand, I have developed and tested on these data a method in order to analyse the neutrinoless double beta decay signal; this method is based on a maximum of likelihood using all the available information. Using this method, I could determine a first and very preliminary upper limit on the effective mass of the neutrino
Tenconi, Margherita. "Development of luminescent bolometers and light detectors for neutrinoless double beta decay search". Thesis, Paris 11, 2015. http://www.theses.fr/2015PA112224/document.
Pełny tekst źródłaNeutrinoless Double Beta Decay (0νDBD) is regarded as an important key in the decryption of some hot astroparticle and cosmological enigmas: it violates lepton number by two units and it is currently the only known practical way to shed light on the neutrino nature, being possible only in case of a Majorana neutrino, identical to its antiparticle. Moreover, the 0νDBD rate is sensitive to the effective neutrino mass, so it would be useful to define the absolute neutrino mass scale and hierarchy. The experimental footprint of 0νDBD is a monochromatic peak in the sum energy spectrum of the two emitted electrons. Next-generation experiments aim at reaching a sensitivity on the effective neutrino mass of the order of ten meV, corresponding to half lives in the range 10²⁷-10²⁸ years: this means to be able to gather, at least, a few hundred kilograms of 0νDBD candidate isotope source and to efficiently scrutinize it with very sensitive detectors. Meanwhile, background levels in the energy region of interest of the 0νDBD signal should be lowered to less than one count/ton/y. Cryogenic luminescent bolometers are a promising technique for 0νDBD search, as they feature excellent energy resolutions, high detection efficiency, flexibility in the material choice and easy scalability to large modular experiments; furthermore, the simultaneous read-out of heat and light signals produced by particle interactions provides an active discrimination method against the dangerous α contaminations, populating the 0νDBD energy region of several interesting candidate isotopes. The work presented in this dissertation was carried out in the context of the LUMINEU project: a pilot experiment focused on zinc molybdate scintillating bolometers, to define the strategies for the construction of a next-generation experiment based on the 0νDBD candidate ¹⁰⁰Mo. In view of the construction of a large 0νDBD experiment, involving hundreds of modules, systematic cryogenic measurements have to be performed to ensure good performance and reproducibility of the detectors and their components. Aboveground facilities are preferred for routinary tests because of their easier accessibility: most of the tests were carried out at CSNSM, where I also worked on the setup of a new cryogenic apparatus, based on the Pulse-Tube technology. One part of my thesis work saw the study of bolometric light detectors based on germanium absorbers and Neutron Transmutation Doped (NTD) thermometers: a proper design was developed in view of LUMINEU and the devices were characterized in terms of sensitivity, energy resolution, baseline noise and reproducibility. The results are compatible with a 0νDBD search final experiment, though this detector configuration is very sensitive to vibrational noise. In addition, the feasibility of bolometric light detectors based on NTD thermometers and Neganov-Luke amplification was investigated, demonstrating that this technique can actually boost the signal-to-noise gain to a level compatible with event discrimination based on Cherenkov light detection. Another part of my work dealt with the test of scintillating zinc molybdate bolometers of mass up to ~300 g, coupled to the aforementioned light detectors and operated both in the aboveground facilities at CSNSM and underground at Modane, in the cryostat of the EDELWEISS Dark Matter search experiment. Good event discrimination capability was achieved: thanks to double read-out of heat and light, it is possible to identify α particles, the threatening background for 0νDBD interests, against β/γ interactions. The results proved the possibility to pre-characterize aboveground detectors of mass close to the one of a final experiment module, despite the high cosmic rays rates. Besides, the measurements opened the way to the mutual compatibility of the underground setup, conceived for another kind of experiment, and LUMINEU 0νDBD search detectors