RESUMO O objetivo deste trabalho foi avaliar o desempenho reprodutivo de nulíparas submetidas à inseminação artificial pós-cervical (IAPC) comparada à inseminação artificial tradicional (IAT). Foram ...avaliados ocorrência de sangramento, ocorrência de refluxo, dificuldade no transpasse da cérvix e total de células refluídas até 30 minutos após inseminação. Fêmeas submetidas à IAPC (n=279) foram inseminadas com doses de 1,5 x 109 diluídas em 45mL, e fêmeas submetidas à IAT (n=273) inseminadas com doses de 2,5 x 109 em 80mL. O transpasse da cérvix foi possível em 91,04% (254/279) das leitoas. A dificuldade no transpasse foi de 41,58% (116/279), não comprometendo o desempenho reprodutivo (P>0,05). Presença de sangramento não afetou a taxa de parto nem o número de leitões nascidos para ambos os tratamentos (P>0,05). O percentual de espermatozoides presentes no refluxo foi maior na IAT, não sendo observada diferença no tamanho de leitegada de acordo com o percentual de espermatozoides no refluxo (P>0,05) e no número de leitões nascidos totais (11,63 e 11,81) entre os tratamentos IAT e IAPC, respectivamente. Pode-se realizar IAPC em leitoas sem causar redução no desempenho, utilizando-se doses com 1,5 x 109 células espermáticas.
Photon flux and spectrum of Compton sources Petrillo, V.; Bacci, A.; Ben Alì Zinati, R. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2012, Letnik:
693
Journal Article
Recenzirano
We analyze the characteristics of the gamma radiation produced by Compton back-scattering of a high brightness electron beam produced by a photoinjector and accelerated in a linac up to energies of ...360-720 MeV and a laser operated at about 500 nm, by comparing classical and quantum models and codes. The interaction produces gamma rays in the range 4.9-18.8 MeV. In view of the application to nuclear resonance fluorescence a relative bandwidth of few 10 - 3 is needed. The bandwidth is reduced by taking advantage of the frequency-angular correlation typical of the phenomenon and selecting the radiation in an angle of tens of Am rads . The foreseen spectral density is 20-6 photons per eV in a single shot, a number that can be increased by developing multi-bunch techniques and laser recirculation. In this way a final value of 10 4 photon per eV per second can be achieved.
In this Letter we report the first experimental observation of the double emittance minimum effect in the beam dynamics of high-brightness electron beam generation by photoinjectors; this effect, as ...predicted by the theory, is crucial in achieving minimum emittance in photoinjectors aiming at producing electron beams for short wavelength single-pass free electron lasers. The experiment described in this Letter was performed at the SPARC photoinjector site, during the first stage of commissioning of the SPARC project. The experiment was made possible by a newly conceived device, called an emittance meter, which allows a detailed and unprecedented study of the emittance compensation process as the beam propagates along the beam pipe.
Phase space analysis of velocity bunched beams Filippetto, D.; Bellaveglia, M.; Castellano, M. ...
Physical review special topics. PRST-AB. Accelerators and beams,
09/2011, Letnik:
14, Številka:
9
Journal Article
Recenzirano
Odprti dostop
Peak current represents a key demand for new generation electron beam photoinjectors. Many beam applications, such as free electron laser, inverse Compton scattering, terahertz radiation generation, ...have efficiencies strongly dependent on the bunch length and current. A method of beam longitudinal compression (called velocity bunching) has been proposed some years ago, based on beam longitudinal phase space rotation in a rf field potential. The control of such rotation can lead to a compression factor in excess of 10, depending on the initial longitudinal emittance. Code simulations have shown the possibility to fully compensate the transverse emittance growth during rf compression, and this regime has been experimentally proven recently at SPARC. The key point is the control of transverse beam plasma oscillations, in order to freeze the emittance at its lowest value at the end of compression. Longitudinal and transverse phase space distortions have been observed during the experiments, leading to asymmetric current profiles and higher final projected emittances. In this paper we discuss in detail the results obtained at SPARC in the regime of velocity bunching, analyzing such nonlinearities and identifying the causes. The beam degradation is discussed, both for slice and projected parameters. Analytical tools are derived to experimentally quantify the effect of such distortions on the projected emittance.
The interaction between high-brilliance electron beams and counterpropagating laser pulses produces x rays via Thomson backscattering. If the laser source is long and intense enough, the electrons of ...the beam can bunch on the scale of the emitted x-ray wavelength and a regime of collective effects can establish. In this case of dominating collective effects, the FEL instability can develop and the system behaves like a free-electron laser based on an optical undulator. Coherent x rays can be irradiated, with a bandwidth very much thinner than that of the corresponding incoherent emission. The emittance of the electron beam and the distribution nonuniformity of the laser energy are the principal quantities that limit the growth of the x-ray signal. In this work we analyze with a 3D code the transverse effects in the emission produced by a relativistic electron beam when it is under the action of an optical laser pulse and the x-ray spectra obtained. The scalings typical of the optical wiggler, characterized by very short gain lengths and overall time durations of the process, make possible considerable emission also in violation of the Pellegrini criterion for static wigglers. A generalized form of this criterion is validated on the basis of the numerical evidence.
Abstract Iso and non-iso architected TiN/Cr multilayers with constant composition were deposited by balanced magnetron sputtering aiming to investigate the influence of different architectures over ...coatings structures and properties. Glow discharge optical emission spectroscopy analyses were used to determine in-depth constituents and suggested that no diffusion of elements occurred between layers in room temperature. Field emission gun scanning electron microscopy analyses showed that all multilayers presented sharp interfaces and low porosity microstructures, with column-like grain growth influenced by layer sizes. Glancing angle X-ray diffraction analyses showed that multilayers consist of polycrystalline α-Cr and δ-TiN phases with a main peak in Cr(110) plane. The overlapping of TiN onto metallic layers led to the suppression of growth in the TiN(111) plane, although TiN layers thicker than 50 nm demonstrated a growth in plane TiN(200). Nanoindentation tests registered equal hardness values for all multilayers of around 16.2 GPa, on the other hand, a tendency to improve hardness has been identified for hierarchical multilayer. Oxidation tests revealed that architectures with thicker TiN top layers presented an improved oxidation resistance up to 600 ºC, probably due to growth in more compact TiN(200) plane. However, TiN/Cr coatings did not resist integrally to oxidation tests at 750 ºC.
Thomson scattering of laser pulses onto ultrarelativistic e-bunches is becoming an advanced source of tunable, quasi-monochromatic, and ultrashort X/gamma radiation. Sources aimed at reaching a high ...flux of scattered photons need to be driven by high-brightness e-beams, whereas extremely short (femtosecond scale or less) sources need to make femtosecond-long e-beams that collide with the laser pulses. In this paper, we explore the performance of the PLASMONX TS source in several operating regimes, including preliminary results on a source based on e-bunches produced by laser wakefield acceleration and controlled injection via density down ramp.
We report on the optical commissioning of the high power laser beam circulator for the high brightness Comptonγ -ray source Extreme Light Infrastructure for Nuclear Physics. Tests aiming at ...demonstrating the optical performances of the laser beam circulator have been realized with a low-power pulsed laser-beam system and without electron beam. We show that, with the developed alignment and synchronization methods coming from the laser beam circulator design study presented in the Dupraz et al. paper Phys. Rev. Accel. Beams 17, 033501 (2014), the laser beam circulator enhances the laser-beam power available at the interaction point by a factor in excess of 25. This corresponds to a potential of bringing the average laser-beam power in excess of 1 kW when the laser beam circulator is injected with the interaction point laser-beam pulse energy of 400 mJ at 100 Hz.
Pure MoSx and MoSx + Hf thin films were deposited by magnetron sputtering and characterized by RBS, GAXRD, XPS, high temperature oxidation tests and tribological tests. Hf content was set at 12 at.% ...by RBS and GAXRD analyses revealed a complete amorphization caused by Hf incorporation. XPS analyses indicated that hafnium is inserted in MoSx in the form of HfSx, moreover, such compound was responsible for inhibiting the formation of MoS. These factors are closely correlated with improvements obtained in oxidation resistance, friction coefficient, wear rate and lifespan of MoSx thin films.
•MoSx and MoSx + Hf thin films were deposited by magnetron sputtering.•Hafnium incorporation promotes a complete amorphization of the coating.•Hafnium atoms are present in the MoSx matrix as HfSx structure.•It was observed MoS structure only for pure MoSx coatings.•MoSx + Hf coating possess better tribological properties when compared to MoSx.
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