Search results for "Instrumentation"
showing 10 items of 4914 documents
Prospects for advanced electron cyclotron resonance and electron beam ion source charge breeding methods for EURISOL
2011
International audience; As the most ambitious concept of isotope separation on line (ISOL) facility, EURISOL aims at producing unprecedented intensities of post-accelerated radioactive isotopes. Charge breeding, which transforms the charge state of radioactive beams from 1+ to an n+ charge state prior to postacceleration, is a key technology which has to overcome the following challenges: high charge states for high energies, efficiency, rapidity and purity. On the roadmap to EURISOL, a dedicated R&D is being undertaken to push forward the frontiers of the present state-of-the-art techniques which use either electron cyclotron resonance or electron beam ion sources. We describe here the gui…
Plasma diagnostic tools for ECR ion sources : What can we learn from these experiments for the next generation sources
2019
International audience; The order-of-magnitude performance leaps of ECR ion sources over the past decades result from improvements to the magnetic plasma confinement, increases in the microwave heating frequency, and techniques to stabilize the plasma at high densities. Parallel to the technical development of the ion sources themselves, significant effort has been directed into the development of their plasma diagnostic tools. We review the recent results of Electron Cyclotron Resonance Ion Source (ECRIS) plasma diagnostics highlighting a number of selected examples of plasma density, electron energy distribution, and ion confinement time measurements, obtained mostly with the second-gener…
All-fibered high-quality low duty-cycle 160-GHz femtosecond pulse source
2008
International audience; In this paper, we report the experimental demonstration of an all-optical fiber-based 160-GHz femtosecond pulse source exhibiting a duty cycle as low as 1/17. The 380-fs wellseparated Gaussian pulses are generated thanks to the strong temporal compression of an initial beat-signal propagating into three distinct segments of optical fiber. Experimental results are supported by numerical simulations based on the generalized nonlinear Schrödinger equation. (© 2008 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA)
Si and Si-rich silicon-nitride waveguides for optical transmissions and nonlinear applications around 2 µm
2019
We show that cm-long silicon and silicon-rich silicon nitride waveguides with subwavelength transverse dimensions can efficiently sustain high-speed transmissions at 2 μm. We report the transmission of a 10 Gbit/s signal with negligible power penalty. Parametric conversion in both continuous and pulsed pump regimes is also demonstrated, as well as the spectral broadening of picosecond pulses.
Hyperfine structure of some near-infrared Xe I and Xe II lines
2011
International audience; This work reports on the experimental determination of the hyperfine splitting of the Xe I lines at 828.01 nm and 834.68 nm and the Xe II line at 834.72 nm. Measurements were performed by means of Doppler-free saturation spectroscopy in a low-pressure radio-frequency discharge. The absolute wavelength of all hyperfine components is obtained by way of a high-precision wavemeter backed-up with the absorption spectrum of the NO 2 molecule. We provide an accurate estimate of hyperfine constants for the lower level of the Xe II transition at 834.72 nm. The two Xe I transition outcomes of our experimental study are compared with data available in the literature.
Micro-Raman investigation of X or gamma irradiated Ge doped fibers
2011
International audience; Micro-Raman spectra have been recorded on Ge doped optical fibers before and after 10 keV-X or c-ray irradiation up to doses of 1 MGy (X-ray) or 7.8 MGy (-ray). Our data provide evidence that, at such dose levels, the glass matrix is not modified in a detectable way. We observed that varying the Ge doping levels from 0 to about 11 wt.%, X or radiation sensitivity of the overall matrix remains unchanged. Such results are observed for fibers obtained with drawing conditions within the usual range used for the fabrication of specialty fibers as radiation-tolerant waveguides. Our data support the potentiality of fiberbased sensors using glass properties, e.g. Raman sc…
Nonlinear sculpturing of optical pulses with normally dispersive fiber-based devices
2018
International audience; We present a general method to determine the parameters of nonlinear pulse shaping systems based on pulse propagation in a normally dispersive fiber that are required to achieve the generation of pulses with various specified temporal properties. The nonlinear shaping process is reduced to a numerical optimization problem over a three-dimensional space, where the intersections of different surfaces provide the means to quickly identify the sets of parameters of interest. We also show that the implementation of a machine-learning strategy can efficiently address the multi-parameter optimization problem being studied.
The Detailed Science Case for the Maunakea Spectroscopic Explorer, 2019 edition
2019
(Abridged) The Maunakea Spectroscopic Explorer (MSE) is an end-to-end science platform for the design, execution and scientific exploitation of spectroscopic surveys. It will unveil the composition and dynamics of the faint Universe and impact nearly every field of astrophysics across all spatial scales, from individual stars to the largest scale structures in the Universe. Major pillars in the science program for MSE include (i) the ultimate Gaia follow-up facility for understanding the chemistry and dynamics of the distant Milky Way, including the outer disk and faint stellar halo at high spectral resolution (ii) galaxy formation and evolution at cosmic noon, via the type of revolutionary…
Radial electron fluence around ion tracks as a new physical parameter for the detection threshold of PADC using Geant4-DNA toolkit
2018
International audience; The detection threshold of poly(allyl dyglycol carbonate), PADC, for C ions is determined as 55 eV/nm in stopping power, which is significantly higher than that for proton and He ions. The stopping power is not a universal parameter for expressing the detection threshold of PADC. A new physical parameter of Radial Electron Fluence around Ion Tracks, REFIT, is proposed to describe the detection threshold of PADC. It is defined as the number density of electrons passing through the surface of a cylinder of a certain radius that is co-axial with the trajectory. Furthermore, preliminary calculations are presently being performed using the Monte Carlo simulation code of G…
Low-cost viscometer based on energy dissipation in viscous liquids
2001
We describe a new type of low-cost easy-to-use viscometer based on the temperature elevation in a liquid under shear flow. After calibration, this instrument can be used to measure the apparent steady state viscosity for both Newtonian and non-Newtonian liquids with no yield stress. We compute the rise in temperature due to viscous dissipation in a Couette cell and compare it to experimental results for different fluids. We show that the variation of the temperature with shear rate can be used to characterize the rheological behaviour of viscous fluids and to evaluate their viscosity in a large domain, from typically a few cP up to more than 10 P, with an accuracy of about ±5%. In contrast …