NUCLEAR TECHNOLOGY

Author: SANTANA LEITNER MARIO.
Year: 2004.
University: POLITÉCNICA DE CATALUÑA [www.upc.edu].
Place of defense: Secció d'Enginyeria Nuclear. ETSEIB..
Place of preparation: EDIFICI B4 Campus NORD.

Summary: Currently the nuclear chart includes around 3000 nuclides, distributed as beta(+-)-emitters, stable and spontaneously fissioning isotopes. A similar amount of unknown nuclei belongs to the so-called terra incognita. The exploration of this zone is to be assisted by the use of radioactive ion beams and could provide a new understanding of several nuclear properties. Moreover, besides pointing at crucial questions such as the validity of the shell model, the dilute matter and the halo structure, challenging experiments outside nuclear physics are also attended, e.g., explanations of the nucleosythesis processes that justify the constitution of the universe. These, together with other fascinating research lines in particle physics, solid state physics and medicine, demand utterly exotic and intense ion beams for which a global optimization of all relevant phenomena in beam formation has to be coherently conducted. As a response to this request, a Monte Carlo code, RIBO (Radioactive Ion Beam Optimizer) has been written, to integrate diffusion and effusion under various pressure flows and conditions, including the transport through continuous media and enabling diffractive and surface dependent effects, emulating ionization in surface and plasma ion sources and, finally, reproducing the movement of ions under electro-magnetic fields. The 1st part is devoted to the implementation of the models, the 2nd applies the resulting program to the analysis of the most important target morphologies. 1st PART: The mathematics of DIFFUSION is treated from the point of view of isotope migration within a bulk target. A diffusion package is developed, tested and applied to typical cases to decouple the effect of gradients of temperature or concentration and of the beam time structure. The implementation of EFFUSION is preceded by a discussion of surface-atom interactions and of the regime of validity of the available models. Diffusive collisions are chosen as default due to the rough nature of working surfaces towards the small De Broglie wave lengths of the impinging atoms. Absorptions are included and the effusion transport is carefully validated. Collisions with residual gas are analyzed for quasi-molecular regimes. Effusion through geometrically undefined media is sketched. IONIZATION in FEBIAD ionizers is emulated by adjusting the cross-section between the moving species and with the concept of mean free path. Surface ionization takes the 'degree of ionization' as key and it reads a set of tables with work functions, ionization potentials and quantum mechanic statistical factors. Maxwell equations under specific assets introduce the IONIC TRANSPORT. 2nd PART: Parallel foil targets are analyzed for the RIST project, minimizing the decay losses without a dramatic drop of the ionization efficiency, and keeping a decent beam emittance. RIBO produces emittance maps for the different geometries of the ionizer. Rolled foil targets are surveyed for the production of n-deficient Krypton isotopes. Target changes are suggested and basic optimization rules for such are established. Powder targets are examined in the frame of the EURISOL project. RIBO is used in conjunction with the multi-particle and evolution codes MCNPX and CINDER, respectively, to predict the yields from a 2-stage fissile target. Finally, the feasibility of a beta-beam neutrino factory is evaluated in terms of the release efficiency of the BeO fiber target. The work concludes with other applications, counting heat-transfer calculations, dosimetry... Two work is completed with two appendices with details of used models and with the RIBO us 8 ers manu 3cb al along with practical examples and a start guide. RIBO is the core of an evolving project; upgrades are produced triggered by the proposals from the growing community of its users or by advances in the installed dependencies. Hence, future releases are expected with new features, more functions and improved interfaces.

Author: PEZZAT SAID ELIAS BERNARDO.
Year: 2004.
University: BARCELONA [www.ub.es].
Place of defense: FACULTAD DE MEDICINA.
Place of preparation: FACULTAD DE MEDICINA.

Summary: We build genetically engineered different expression vectors micobacteriano, from vectors parental pMV261 and pMV361. It developed 3 strains expressing recombinant BCG protein complete gp120 of the wrapped HIV strain (HXBC2). We evaluated different promoters BCG to induce the expression of heterologous protein of HIV. Initially, we used the promoter hsp60 BCG, a strong promoter that has proven to be one of the most efficient and subsequently tested with a promoter weak denominado- antigen. Once obtained different recombinant BCG strains was evaluated in vitro expression of the protein by Western blot technique. Then we evaluate in vivo cell-specific immune response in a murine animal model. Mice were immunized with the strains BCGr: 222VIHA, BCGr: 223VIHA and strain modified vaccinia virus Ankara (MVA) expressing the inmunogeno of VIHA for the whole protein and gag wrapped subtype A predominant in eastern Africa, most of different etpítopos CTL nef, pol. The answer specific T cells CD8 + was detected by staining of tetrámeros and staining of intracellular IFN. Finally to overcome limitations in the differentiation inducing cytokines between BCG (wild strain) and BCGr by ELISPOT technique, we evaluated the expression géncia of IFN. Since lymphocytes mouse, delectando on this cytokine mRNA by RT-PCR technique. Contributions of the thesis: * Design and development, genetic engineering and molecular biology of 3 vaccine strains of recombinant BCG. BCGr: 261 VIH-1gp120 BCGr: 222 VIH-1gp120 BCGr: 223 VIH-1gp120 * Survey and description of readjustment genetic strain that produces wild, when it is transformed by the expression vector micobacteriano pMV261 including conado piece of DNA that encodes the protein of HIV-1 gp 120 and culmunio with delección it. (This study was presented in a poster at the World Conference on HIV Vaccine Switzerland in Lausanne in September. 2004). * The results of the preclinical studies, to evaluate the immunogenicity of our vaccine strains, to induce T cell CD8 specific response against HIV-1 in mice, as assessed by different techniques, provide useful lessons for future trials concerning dosage , routes of administration and employee scheme, as well as the selection of this technique to detect immune response.

Author: BALLESTER BERMAN DANIEL.
Year: 2005.
University: POLITÉCNICA DE VALENCIA [www.upv.es].
Place of defense: Dep. Ingenieria Quimica y Nuclear.
Place of preparation: Universidad Politécnica de Valencia.

Summary: In recent years, scientists in various areas have shown a great interest in the conceptual development of the so-called nuclear systems excited accelerator accelerator-driven systems, ADS) due to the possible application of these as reactors transmutadores and energy producers. One of the fundamental issues to resolve in order to make possible the industrial use of this type of reactor is the development of techniques for measuring and Periodic monitoring of the level of subcriticidad, since both safety in the operation, as well as its performance as one of the stages that make up the nuclear fuel cycle, will depend heavily on this variable. Using methods based on the study of neutron fluctuations in multiplicative media excited by external sources not markovianas time-dependent has attracted increasing attention during recent experiments in the European project MUSE, conducted in the reactor subcritical MASURCA (Cadarache, France ). In these experiments have been used from external sources neutron reactions DD and DT, but has also raised the possibility of using external sources spallation. Whatever the case, the measures can be implemented in two ways: first, the window of neutron detector can be synchronized with the injection of a pulse of the external source, and this method is called deterministic method pressed while, on the other hand, the relative delay between injection of a pulse and the beginning of time for counting detector can be sampled evenly between zero and the value of the period of the pulsed source, so that this method is called method pressed stochastic. The mathematical description used in this work is based on the use of some well-known results of the theory of generating functions in order to derive equations that relate the probability generating function of the source generating the role of probabiliad kernel for various probleams transport stochastic neutron that take into account the nature markoviana not dela neutron source. These equations, along with a description of the probability generating function of kernel, will enable us to obtain different statistical problems with one or more detectors. In addition, it has undertaken a development modes alpha neutron flux for all statistical study. The contribution of higher harmonics in trouble monitoring systems subcritical may become important reactor type ADS, so that the excitation of these higher harmonics can occur even in situations of normal operation. This possibility increases as the reactor is far from the status of criticality. This paper has neglected the contribution of delayed neutrons, hence all quantities that appear to be construed as variables snapshots, valid for time scales comparable to the average life of the precursors of delayed neutrons.