[en] A summary of the results of several recent studies of charm mixing is presented. A number of different methods were used, including the measurement of lifetime ratios for final states of different CP, time dependence of wrong-sign hadronic decays, fits to time-dependent Dalitz plots, and searches for wrong-sign semi-leptonic decays. Taken together, they suggest mixing is of order 1%. The status of searches for indirect CP violation is also reported

[en] The results of several studies of charmed mesons and baryons at BABAR are presented. First, searches for the rare decays D⁰ → l⁺l^- are presented and new upper limits on these processes are established. Second, a measurement of the branching fraction of the isospin-violating hadronic decay D*_s(2112)⁺ → D_s⁺π⁰ relative to the radiative decay D*_s(2112)⁺ → D_s⁺γ is made. Third, the decays of D*_sJ(2317)⁺ and D_sJ(2460)⁺ mesons are studied and ratios of branching fractions are measured. Fourth, Cabibbo-suppressed decays of the Λ_c⁺ are examined and their branching fractions measured relative to Cabibbo-allowed modes. Fifth, the Χ_c⁰ is studied through its decays to Χ^-π⁺ and (Omega)^-K⁺; in addition to measuring the ratio of branching fractions for Χ_c⁰ produced from the c(bar c) continuum, the uncorrected momentum spectrum is measured, providing clear confirmation of Χ_c⁰ production in B decays

[en] The Next Generation Nuclear Plant (NGNP)/Advanced Gas Reactor (AGR) Fuel Development and Qualification Program includes a series of irradiation experiments in Idaho National Laboratory's (INL's) Advanced Test Reactor. TRISO coated particles for the first AGR experiment, AGR-1, were produced at Oak Ridge National Laboratory (ORNL) in a two inch diameter coater. A requirement of the NGNP/AGR Program is to produce coated particles for later experiments in coaters more representative of industrial scale. Toward this end, tests have been performed by Babcock and Wilcox (B and W) in a six-inch diameter coater. These tests are expected to lead to successful fabrication of particles for the second AGR experiment, AGR-2. While a thorough study of how coating parameters affect particle properties was not the goal of these tests, the test data obtained provides insight into process parameter/coated particle property relationships. Most relationships for the six-inch diameter coater followed trends found with the ORNL two-inch coater, in spite of differences in coater design and bed hydrodynamics. For example the key coating parameters affecting pyrocarbon anisotropy were coater temperature, coating gas fraction, total gas flow rate and kernel charge size. Anisotropy of the outer pyrolytic carbon (OPyC) layer also strongly correlates with coater differential pressure. In an effort to reduce the total particle fabrication run time, silicon carbide (SiC) was deposited with methyltrichlorosilane (MTS) concentrations up to 3 mol %. Using only hydrogen as the fluidizing gas, the high concentration MTS tests resulted in particles with lower than desired SiC densities. However when hydrogen was partially replaced with argon, high SiC densities were achieved with the high MTS gas fraction

[en] A major element of the Advanced Gas Reactor (AGR) program is developing fuel fabrication processes to produce high quality uranium-containing kernels, TRISO-coated particles and fuel compacts needed for planned irradiation tests. The goals of the AGR program also include developing the fabrication technology to mass produce this fuel at low cost. Kernels for the first AGR test (AGR-1) consisted of uranium oxycarbide (UCO) microspheres that were produced by an internal gelation process followed by high temperature steps tot convert the UO3 + C 'green' microspheres to first UO2 + C and then UO2 + UCx. The high temperature steps also densified the kernels. Babcock and Wilcox (B and W) fabricated UCO kernels for the AGR-1 irradiation experiment, which went into the Advance Test Reactor (ATR) at Idaho National Laboratory in December 2006. An evaluation of the kernel process following AGR-1 kernel production led to several recommendations to improve the fabrication process. These recommendations included testing alternative methods of dispersing carbon during broth preparation, evaluating the method of broth mixing, optimizing the broth chemistry, optimizing sintering conditions, and demonstrating fabrication of larger diameter UCO kernels needed for the second AGR irradiation test. Based on these recommendations and requirements, a test program was defined and performed. Certain portions of the test program were performed by Oak Ridge National Laboratory (ORNL), while tests at larger scale were performed by B and W. The tests at B and W have demonstrated improvements in both kernel properties and process operation. Changes in the form of carbon black used and the method of mixing the carbon prior to forming kernels led to improvements in the phase distribution in the sintered kernels, greater consistency in kernel properties, a reduction in forming run time, and simplifications to the forming process. Process parameter variation tests in both forming and sintering steps led to an increased understanding of the acceptable ranges for process parameters and additional reduction in required operating times. Another result of this test program was to double the kernel production rate. Following the development tests, approximately 40 kg of natural uranium UCO kernels have been produced for use in coater scale up tests, and approximately 10 kg of low enriched uranium UCO kernels for use in the AGR-2 experiment

[en] Hydrogen extraction from the gaseous mixture CH₄P, H₂, N₂, NH₃, O₂, H₂O, CO₂, occurring as impurities has been performed by chemical reaction with uranium metal - Thermodynamical and kinetical investigations have confirmed hydrogen could be purified by this process, but experiments performed at 973 K point out the importance of the interferences that can occur in the system uranium - gas mixture. The aim of the study is purification of burned gases exhausted from the plasma chamber of a fusion device to recover tritium content of impurities linked with hydrogen atoms

[en] The 18 KW Rigaku high brilliance rotating anode X-ray source with four-circle qoniometer is used for X-ray diffraction characterization on thin films. This X-ray source can determine the crystal structures of a wide variety of thin materials of the type used in the semiconductor and magnetic data storage industries

[en] Three task actions are presented in this report: on hydrogen extraction from a gas mixture, on elements for tritium recovery from the fusion reactor ceramic blanket, and on large components for the torus vacuum circuits

[en] Within the framework of the european fusion program, we are dealing with the purification of hydrogen (tritium) under a free or combined form, from a H₂, N₂, NH₃, CH₄, O₂, gaseous mixture. The process consists in cracking the hydrogenated molecules and absorbing the impurities by chemical reactions with uranium, without holding back hydrogen. In the temperature range: 950 K < T < 1200 K hydrides are indeed fully decomposed for hydrogen partial pressures lower than ten atmospheres while uranium oxides, nitrides and carbides formation reactions are promoted. The experiments are carried out with massive uranium heated at 973 K in a closed reactor. They confirm that such a process may satisfy our goals, but they point out the importance of interactions occurring between the gaseous and solids systems and interfere with the conversion rates. Gaseous pressure decreases with time according to two successive phases: the first one is governed by a surface kinetic law, while after a short transition time, gas diffusion in the solid products arises and becomes the limiting step of the reactions. Experimental results with pure gases and mixtures, prove that solid products have different structures. An illustrative example is given by nitrogen and methane reactions with uranium: the solid layers are compactely formed with each pure gas and they slow down the chemical kinetic rates; on the contrary the chemical kinetic rates of the mixed gases reactions are clearly increased and the diffusional rates are postponed. Then, the compacity of the solid products merely depends on the operating conditions and the influence of the reactional surface state on the chemical kinetic rates is here pointed out

[en] With the requirement for more protons per hour from Booster, the radiation is a limiting factor. The most important periods in a Booster accelerating cycle are injection and transition crossing. The laser notching H^- beam at the Booster injection RF frequency can make a bucket-to-bucket transfer from Linac to Booster possible, and this should remove most of the capture loss at injection and the early beam loss in the cycle. Besides that, the variation of the laser pulse length can change the notch length of the H^- beam such that the bucket area filled by the beam can be controlled, and this can be applied to control the longitudinal emittance of the Booster beam

[en] With the requirement for more protons per hour from Booster, the radiation is a limiting factor. Laser notching the H^- beam at the Booster injection revolution frequency and properly aligning those notches on top of each other at the injection and relative to the trigger of firing extraction kickers can remove most of the extraction loss caused by the slow rise time of the kicker field