282 research outputs found
Conceptual design of electron beam diagnostics for high brightness plasma accelerator
A design study of the diagnostics of a high brightness linac, based on X-band
structures, and a plasma accelerator stage, has been delivered in the framework
of the EuPRAXIA@SPARC_LAB project. In this paper, we present a conceptual
design of the proposed diagnostics, using state of the art systems and new and
under development devices. Single shot measurements are preferable for plasma
accelerated beams, including emittance, while m level and fs scale beam
size and bunch length respectively are requested. The needed to separate the
driver pulse (both laser or beam) from the witness accelerated bunch imposes
additional constrains for the diagnostics. We plan to use betatron radiation
for the emittance measurement just at the end of the plasma booster, while
other single-shot methods must be proven before to be implemented. Longitudinal
measurements, being in any case not trivial for the fs level bunch length, seem
to have already a wider range of possibilities
Multi-GeV Electron Spectrometer
The advance in laser plasma acceleration techniques pushes the regime of the
resulting accelerated particles to higher energies and intensities. In
particular the upcoming experiments with the FLAME laser at LNF will enter the
GeV regime with almost 1pC of electrons. From the current status of
understanding of the acceleration mechanism, relatively large angular and
energy spreads are expected. There is therefore the need to develop a device
capable to measure the energy of electrons over three orders of magnitude (few
MeV to few GeV) under still unknown angular divergences. Within the PlasmonX
experiment at LNF a spectrometer is being constructed to perform these
measurements. It is made of an electro-magnet and a screen made of
scintillating fibers for the measurement of the trajectories of the particles.
The large range of operation, the huge number of particles and the need to
focus the divergence present unprecedented challenges in the design and
construction of such a device. We will present the design considerations for
this spectrometer and the first results from a prototype.Comment: 7 pages, 6 figures, submitted to NIM
Longitudinal phase-space manipulation with beam-driven plasma wakefields
The development of compact accelerator facilities providing high-brightness
beams is one of the most challenging tasks in field of next-generation compact
and cost affordable particle accelerators, to be used in many fields for
industrial, medical and research applications. The ability to shape the beam
longitudinal phase-space, in particular, plays a key role to achieve high-peak
brightness. Here we present a new approach that allows to tune the longitudinal
phase-space of a high-brightness beam by means of a plasma wakefields. The
electron beam passing through the plasma drives large wakefields that are used
to manipulate the time-energy correlation of particles along the beam itself.
We experimentally demonstrate that such solution is highly tunable by simply
adjusting the density of the plasma and can be used to imprint or remove any
correlation onto the beam. This is a fundamental requirement when dealing with
largely time-energy correlated beams coming from future plasma accelerators
Temperature analysis in the shock waves regime for gas-filled plasma capillaries in plasma-based accelerators
Plasma confinement represents a crucial point for plasma-based accelerators and plasma lenses because it can strongly affect the beam properties. For this reason, an accurate measurement of the plasma parameters, as plasma temperature, pressure and electron density, must be performed. In this paper, we introduce a novel method to detect the plasma temperature and the pressure for gas-filled capillaries in use at the SPARC-LAB test facility. The proposed method is based on the shock waves produced at the ends of the capillary during the gas discharge and the subsequent plasma formation inside it. By measuring the supersonic speed of the plasma outflow, the thermodynamic parameters have been obtained both outside and inside the capillary. A plasma temperature around 1.4 eV has been measured, that depends on the geometric properties and the operating conditions of the capillary
Focusing of high-brightness electron beams with active-plasma lenses
Plasma-based technology promises a tremendous reduction in size of accelerators used for research, medical, and industrial applications, making it possible to develop tabletop machines accessible for a broader scientific community. By overcoming current limits of conventional accelerators and pushing particles to larger and larger energies, the availability of strong and tunable focusing optics is mandatory also because plasma-accelerated beams usually have large angular divergences. In this regard, active-plasma lenses represent a compact and affordable tool to generate radially symmetric magnetic fields several orders of magnitude larger than conventional quadrupoles and solenoids. However, it has been recently proved that the focusing can be highly nonlinear and induce a dramatic emittance growth. Here, we present experimental results showing how these nonlinearities can be minimized and lensing improved. These achievements represent a major breakthrough toward the miniaturization of next-generation focusing devices
The step of incorporation of Bacillus coagulans GBI-30 6086 into “requeijão cremoso” processed cheese does not affect metabolic homeostasis of rats
Dairy product consumption is a common habit in Brazil. These products present a good matrix for probiotic incorporation. Thus, in this study the feasibility of producing a probiotic "requeijao cremoso" incorporated with Bacillus coagulans GBI-30 6086 in three different steps and its metabolic effect in an animal model for 2 weeks has been evaluated. Wistar adult health rats were randomized into one to five groups (n = 8 for each group): Control (C); "requeijao cremoso" without probiotic (RC); probiotic inoculated in the milk before pasteurization at 65 degrees C/30 min (RPP); "requeijao cremoso" inoculated before the fusion step and consequently exposed to 90 degrees C/5 min (RPF); and "requeijao cremoso" inoculated after fusion step, i.e., once the product temperature reached 50 degrees C (RPAF). At the end of treatment, analysis of molecular markers of proteins of stress and antioxidant system, HSP 25, 60, 70 and 90, SOD and catalase were performed in the animals' muscles by Western Blot technique. The HSP25, HSP90 and catalase levels of C, RPP, RPF, and RPAF were similar, indicating that the homeostasis remained unchanged. The incorporation of B. coagulans GBI-30 6086 in the "requeijao cremoso" was shown to be stable and the microorganism remained viable in all steps tested. The incorporation of the probiotic strain in the fusion stage facilitated the technological process, since it allowed a better homogenization of the product and did not affect the maintenance of the metabolic homeostasis of rats10CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPsem informação302763/2014-7; 305804/2017-013/21544-9; 18/24540-8; 2019/21188-
Ligand-Receptor Interactions
The formation and dissociation of specific noncovalent interactions between a
variety of macromolecules play a crucial role in the function of biological
systems. During the last few years, three main lines of research led to a
dramatic improvement of our understanding of these important phenomena. First,
combination of genetic engineering and X ray cristallography made available a
simultaneous knowledg of the precise structure and affinity of series or
related ligand-receptor systems differing by a few well-defined atoms. Second,
improvement of computer power and simulation techniques allowed extended
exploration of the interaction of realistic macromolecules. Third, simultaneous
development of a variety of techniques based on atomic force microscopy,
hydrodynamic flow, biomembrane probes, optical tweezers, magnetic fields or
flexible transducers yielded direct experimental information of the behavior of
single ligand receptor bonds. At the same time, investigation of well defined
cellular models raised the interest of biologists to the kinetic and mechanical
properties of cell membrane receptors. The aim of this review is to give a
description of these advances that benefitted from a largely multidisciplinar
approach
Recent results at SPARC_LAB
The current activity of the SPARC_LAB test-facility is focused on the
realization of plasma-based acceleration experiments with the aim to provide
accelerating field of the order of several GV/m while maintaining the overall
quality (in terms of energy spread and emittance) of the accelerated electron
bunch. In the following, the current status of such an activity is presented.
We also show results related to the usability of plasmas as focusing lenses in
view of a complete plasma-based focusing and accelerating system
Turning the attentional blink on and off: Opposing effects of spatial and temporal noise
First emittance measurement of the beam-driven plasma wakefield accelerated electron beam
Next-generation plasma-based accelerators can push electron beams to GeV
energies within centimetre distances. The plasma, excited by a driver pulse, is
indeed able to sustain huge electric fields that can efficiently accelerate a
trailing witness bunch, which was experimentally demonstrated on multiple
occasions. Thus, the main focus of the current research is being shifted
towards achieving a high quality of the beam after the plasma acceleration. In
this letter we present beam-driven plasma wakefield acceleration experiment,
where initially preformed high-quality witness beam was accelerated inside the
plasma and characterized. In this experiment the witness beam quality after the
acceleration was maintained on high level, with final energy spread and
resulting normalized transverse emittance after the acceleration.
In this article, for the first time to our knowledge, the emittance of the PWFA
beam was directly measured
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