>Magister Scientiae - MSc / High spin excited stats in¹⁹²Tl were studied using gamma-ray spectroscopy. The study included taking an active part in performing the experiment, understanding the experimental procedure, electronics and data acquisition in this experiment. The high spin states in ¹⁹²Tl were produced using a ³⁷Cl beam and ¹⁶⁰Gd target. The nine clovers of the AFRODITE array were placed at 90° and 135°. The target was thin, allowing the residual thallium nuclei to recoil in vacuum. Two weeks of data was acquired and analysed in this work. In addition more data was acquired in order to perform DSAM lifetime measurements, but this is beyond the scope of this work. The preliminary data analysis of the thin target data involved energy and time-gain matching calibrations as well as Doppler shift and gain drift corrections. Then the data were sorted into matrices and spectra for the actual analysis. The known level scheme of ¹⁹²Tl was extended by more than 50 new transitions placed in three new bands. A chiral partner to the yrast band in ¹⁹²92Tl was searched for but not found. But there is still a possibility such a band to be discovered, when the additional three weekends of data (including the DSAM lifetime measurements) undergo such an analysis.

Dans le cadre de la mission de surveillance radiologique de l’environnement de l’Institut de Radioprotection et de Sûreté Nucléaire (IRSN), le Laboratoire de Mesure de la Radioactivité dans l’Environnement (LMRE) réalise la mesure de la concentration en activité dans différentes matrices environnementales. Il s’agit de matrices biologiques (mousses aquatiques, algues, lait, légumes …), de sols, d’eaux ou encore de filtres de prélèvement d’aérosols.Les radionucléides artificiels recherchés sont en très faible proportion par rapport à certains radionucléides naturels : le potassium 40 dans les matrices biologiques ou encore les descendants particulaires du radon dans les filtres d’aérosols. L’important fond Compton induit par ces radionucléides naturels dans le spectre gamma complique la détermination des radionucléides présents au niveau trace.Un moyen de s’affranchir de ce fond Compton est de faire une mesure par spectrométrie $gamma$ en coïncidence en utilisant au moins deux détecteurs. La méthode a été développée sur un système existant, le système anti-Compton constitué d’un détecteur germanium entouré d’un scintillateur NaI(Tl), avec le développement d’un algorithme d’analyse et de l’étalonnage par simulation Monte Carlo si nécessaire. De plus, un nouveau système de mesure en coïncidence a été conçu par simulation Monte Carlo puis mis en service pour pallier les limites du système anti-Compton. Ce nouveau système de mesure, nommé Léda, est composé de deux détecteurs germanium face à face, entourés d’un scintillateur NaI(Tl) ; il possède plusieurs voies de mesure, chacune présentant une amélioration en termes de limite de détection pour tous les radionucléides mesurés. / The French Institute of Radiation Protection and Nuclear Safety (IRSN) is in charge of the radiological surveillance of the environment. In this framework the Laboratory of Environment Radioactivity Measurement (LMRE) measures the radioactivity concentrations in various environmental samples: biological matrices (aquatic moss, seaweed, milk, vegetables …), soils, waters or aerosol filters.Artificial radionuclides searched are in low proportion compared to natural radionuclides: potassium 40 in biological matrices or radon particular daughters in aerosol filters. The significant Compton continuum induced in the gamma spectrum makes difficult the identification and the quantification of radionuclides present at trace level.The use of two detectors enables to make coincident spectrometry in order to decrease this Compton background. This technique was developed with an existing system of the laboratory, the anti-Compton system, composed of a germanium detector surrounded by a NaI(Tl) scintillator. A data analysis algorithm was developed and also a Monte Carlo calibration if radionuclides measured are not available in standard source. Moreover a new coincident measurement system was designed by Monte Carlo simulation, called Leda consisting of two germanium detectors face to face surrounded by a NaI(Tl) scintillator. This new system overcomes the limits of the anti-Compton system. Different measurement channels improve the detection limits for all radionuclides measured in our laboratory.

Yes / An ability to predict the time-to-contact (TTC) of moving objects that become momentarily hidden is advantageous in everyday life and could be particularly so in fast-ball sports. Prediction motion (PM) experiments have sought to test this ability using tasks where a disappearing target moves towards a stationary destination. Here, we developed two novel versions of the PM task in which the destination either moved away from (Chase) or towards (Attract) the moving target. The target and destination moved with different speeds such that collision occurred 750, 1000 or 1250ms after target occlusion. To determine if domain-specific experience conveys an advantage in PM tasks, we compared the performance of different sporting groups ranging from internationally competing athletes to non-sporting controls. There was no difference in performance between sporting groups and non-sporting controls but there were significant and independent effects on response error by target speed, destination speed and occlusion period. We simulated these findings using a revised version of the linear TTC model of response timing for PM tasks (Yakimoff et al. 1987, 1993) in which retinal input from the moving destination biases the internal representation of the occluded target. This revision closely reproduced the observed patterns of response error and thus describes a means by which the brain might estimate TTC when the target and destination are in motion.

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The design and construction of a coincidence spectrometer and its application to the study of the decay of Os¹⁹³ are presented. / Thesis / Doctor of Philosophy (PhD)

<p> The level structure of the Odd-A nucleus 163Lu has been studied by the 148Sm (19F,4n) 163Lu reaction through gamma-ray singles and gamma-gamma coincidence methods.</p> <p> A number of rotational band structures have been observed up to a spin of 43/2. The backbending behaviour of the two signatures of the h11/2 band, α = -1/2 and α = 1/2, has been observed. The critical frequencies for the backbends are wc = 0.264 and 0.284 respectively.</p> / Thesis / Master of Science (MSc)

My goal in this dissertation is to analyze the question, why is co-location a problem for the metaphysics of material objects? I believe that the existing literature on the topic identifies three possible answers to this question: Either, (i) co-location is a problem because it violates the no-coincidence principle, or because (ii) co-location violates the claim that the best available explanation for the relationship between objects that share the same empirically discriminable properties is the relationship of numerical identity, or finally because (iii) co-location violates the thesis of microphysical determination. I argue that (i), (ii), and (iii) are not sufficient reasons to think that co-location is metaphysically problematic, and that a denial of these assumptions does not warrant a rejection of co-location. I maintain that, instead, if co-location is a problem, it is so in virtue of violating a more basic assumption. Co-location is a problem for the view that the individuation and persistence conditions of any given material object is completely and solely determined by the physical or material properties of such an object. I advance reasons to believe that the latter view is fundamental in the sense that (i), (ii), and (iii), are consequences of it, and that co-location is in conflict with (i), (ii) and (iii), because it questions the basic physicalist view that provides the conditions for (i), (ii), and (iii). The fact that (i), (ii) and (iii) depend on the belief that physical properties exhaust the individuation and persistence of material objects, explains why they are not good reasons against co-location: They cannot establish that co-location is a problem for an account of material objects because they depend on the belief that co-location denies. Therefore, (i), (ii), and (iii) provide no more than three different ways of begging the question against co-location. I argue that, in order to show that co-location is a problem, we must show that physicalism with respect to material objects is the correct, or at least the most plausible, metaphysics of material objects, and this is something that neither (i), (ii), or (iii) can show. This statement of the relationship between co-location and anti-colocation reasons is also a contribution to the discussion of co-location. / Philosophy

Orientador: Alice Kimie Miwa Libardi / Banca: Edson de Oliveira / Banca: Thiago de Melo / Resumo: O principal objetivo deste trabalho é apresentar conceitos básicos sobre coincidências e pontos fixos de aplicações contínuas usando como ferramentas os Lemas Combinatórios de Sperner e grau de aplicações. Apresentamos também um cálculo do número de Lefschetz de f; g : T2 ¡! T3, onde Th denota uma superfície de genus h, através da fórmula dada por Gonçalves e Oliveira em [3] / Abstract: The main goal of this work is present basic concepts on coincidences and fixed points of continuous maps with Sperner's Combinatorial Lemmas, and degree maps approaches. We also present a calculation of the Lefschetz number of f; g : T2 ¡! T3, where Th denotes surface of genus h, by using the formula given by Gonçalves and Oliveira in [3] / Mestre

A fully functioning Comprehensive nuclear-Test-Ban Treaty (CTBT) is essential for a world free of nuclear weapons. To measure radionuclides in the atmosphere in accordance with the CTBT, facilities such as SAUNA uses double coincidence techniques to discriminate between interesting Xenon isotopes. In this paper, a Monte-Carlo code (open source) based on first principles simulating a radionuclide detector has been built to investigate the viability of triple coincidence methods for measurements of $^{131m}$Xe, $^{133m}$Xe, $^{133}$Xe and $^{135}$Xe and found that by measuring $\beta - $ Ce $-$ X-ray coincides in $^{133}$Xe and $^{135}$Xe one could seperate the 30 keV photon energy region of interest by as much as $42.9 \pm 26.8$ keV and $214 \pm 50.8$ keV away from the original electron $-$ photon energy axes measured in SAUNA, using concentrations of Xenon isotopes typical for a nuclear weapons test one day after testing. The conclusion is that triple  coincidence  is  a  viable  method  for  nuclear weapons detection in light of double coincidence methods,  if only considering this  theoretical  approach.   No  conclusions  on  the  practicality  of  triple  coincidence methods in a CTBT could be drawn from these results.