Search results for "Ion laser"
showing 10 items of 19 documents
Hot-cavity studies for the Resonance Ionization Laser Ion Source
2016
International audience; The Resonance Ionization Laser Ion Source (RILIS) has emerged as an important technique in many Radioactive Ion Beam (RIB) facilities for its reliability, and ability to ionize target elements efficiently and element selectively. GISELE is an off-line RILIS test bench to study the implementation of an on-line laser ion source at the GANIL separator facility. The aim of this project is to determine the best technical solution which combines high selectivity and ionization efficiency with small ion beam emittance and stable long term operation. The ion source geometry was tested in several configurations in order to find a solution with optimal ionization efficiency an…
Development of LIBS for online analysis of solid nuclear materials
2015
With the objective to implement a fast, online analysis technique for control of solid metal nuclear materials, laser-induced breakdown spectroscopy (LIBS) technique is developed for quantitative analysis in uranium and plutonium. Since these matrices have a very dense emission spectrum in the UV-Visible range, the Vacuum Ultra-Violet (VUV) spectral range, less rich in lines, is explored. The aim of this thesis is to perform the analytical development of VUV-LIBS for quantitative analysis between 500 and 5000 ppm with an uncertainty of 3%. For that purpose, four steps were defined. First, for practical and safety reasons, it is generally better to perform experiments on surrogate materials.…
Thermal sprayed coatings for protection against cavitation erosion
2018
In order to protect the hydraulic components from cavitation erosion phenomena, the parts are often coated by thermal spraying. Buck YSZ shows an excellent performance against cavitation erosion. However, the cavitation erosion resistance of YSZ coatings have vaguely been studied. Therefore, in this study, YSZ were manufactured with different thermal spraying processes and post-treated by laser remelting, then they were subjected to cavitation tests according to ASTM G32.The YSZ coating was first manufactured by atmospheric plasma spraying (APS). Various sizes of YSZ powder and different preheating temperatures of the substrate were studied to observe their effect on the cavitation behavior…
High resolution spectroscopy and potential determination of the (3)1Pi state of NaCs.
2006
The (3)(1)Pi state of the NaCs molecule was studied by high resolution Fourier-transform spectroscopy. The (3)(1)Pi--X (1)Sigma(+) laser induced fluorescence was excited by an Ar(+) ion laser or by a single-mode frequency-doubled cw Nd:YAG laser. The presence of argon buffer gas yielded rich rotational relaxation spectra allowing to enlarge the data set for the (3)(1)Pi state term values, as well as to observe Lambda splittings in a wide range of vibrational (v(')) and rotational (J(')) quantum numbers. The data field includes about 820 energy levels of (3)(1)Pi NaCs in the range from v(')=0 to 37 and from J(')=3 to 190, which corresponds to ca. 95% of the potential well depth. Direct fit o…
Inelastische Lichtstreuung von Cellulosenitratlösungen
1974
Es wird ein Homodyngerat zur Messung der inelastischen Lichtstreuung beschrieben, das mit einem Argon-Ionenlaser ausgerustet ist und mit einem Autokorrelator arbeitet. Das Gerat wird benutzt, um das Verhalten der Fadenmolekule von Cellulosenitrat in verdunnter Losung zu untersuchen. Mit dieser Technik wird es moglich, sogar fur unabgebaute native Cellulose die Diffusionskoeffizienten der Translation D zu bestimmen, die ein sehr niedriges D (<10−7 cm2 s−1) aufweisen und bisher nur naherungsweise bekannt waren, da die konventionellen Mestechniken der optischen Beobachtung eines Konzentrationsausgleiches dann recht ungenau werden. A homodyne light beat spectrometer equipped with an argon ion l…
Photosensitivity of SiO2–Al and SiO2–Na glasses under ArF (193 nm) laser
2009
Abstract Photosensitivity of SiO 2 –Al and SiO 2 –Na glass samples was probed by means of the induced optical absorption and luminescence as well as by electron spin-resonance (ESR) after irradiation with excimer-laser photons (ArF, 193 nm). Permanent visible darkening in the case of SiO 2 –Al and transient, life time about one hour, visible darkening in the case of SiO 2 –Na was found under irradiation at 290 K. No darkening was observed at 80 K for either kind of material. This investigation is dedicated to revealing the electronic processes responsible for photosensitivity at 290 and 80 K. The photosensitivity of both materials is related to impurity defects excited directly in the case …
On-line implementation and first operation of the Laser Ion Source and Trap at ISOLDE/CERN
2015
13 pags.; 12 figs.; 2 tab.; Open Access funded by CERN
Laser ablation of a turbid medium : Modeling and experimental results.
2006
International audience; Q -switched Nd:YAG laser ablation of a turbid medium (paint) is studied. The optical properties (absorption coefficient, scattering coefficient, and its anisotropy) of a paint are determined with a multiple scattering model (three-flux model), and from measurements of reflection-transmission of light through thin layers. The energy deposition profiles are calculated at wavelengths of 532 nm and 1.064 $\mu$m. They are different from those described by a Lambert-Beer law. In particular, the energy deposition of the laser beam is not maximum on the surface but at some depth inside the medium. The ablated rate was measured for the two wavelengths and compared with the en…
Regulation of cholesterol metabolism in the retina under experimental conditions associated with glaucoma
2019
Cholesterol is a lipid found in every animal cell and is necessary for its survival. Among its multiple roles in the body, it is a component of cell membranes that is crucial for the maintenance of their structure and fluidity and is thus implicated in the modulation of many signalling pathways. Neurons are especially dependant on cholesterol input since the proper composition of their plasma membrane is required for vesicular exocytosis of neurotransmitters and transduction of the post-synaptic signal. It has been shown that both an excess and a lack of cholesterol is neurotoxic. Moreover, many neurodegenerative diseases, such as Alzheimer’s or Huntington’s disease, have been associated wi…
Resonance ionization schemes for high resolution and high efficiency studies of exotic nuclei at the CRIS experiment
2019
© 2019 This paper presents an overview of recent resonance ionization schemes used at the Collinear Resonance Ionization Spectroscopy (CRIS) setup located at ISOLDE, CERN. The developments needed to reach high spectral resolution and efficiency will be discussed. Besides laser ionization efficiency and high resolving power, experiments on rare isotopes also require low-background conditions. Ongoing developments that aim to deal with beam-related sources of background are presented. ispartof: Nuclear Instruments & Methods In Physics Research Section B-Beam Interactions With Materials And Atoms vol:463 pages:398-402 ispartof: location:SWITZERLAND, CERN, Geneva status: published