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Picardi, L.; Messina, G.; Ronsivalle, C.; Vignati, A.
Proceedings of the 1992 linear accelerator conference1992
Proceedings of the 1992 linear accelerator conference1992
AbstractAbstract
[en] In the last ten years four small linear accelerators have been built at the ENEA Frascati Center, used for a 100 MeV racetrack microtron and for electron beam processing tests of materials. ENEA is also involved in infrared free electron laser (FEL) research. After good results from a 2 mm wavelength FEL driven by a 2.5 MeV linac, design has been started on a linac for a far infrared FEL facility devoted to an experiment in muonic hydrogen spectroscopy. 3 figs., 3 tabs., ref
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Hoffmann, C.R. (ed.); Atomic Energy of Canada Ltd., Chalk River, ON (Canada). Chalk River Nuclear Labs; 949 p; Nov 1992; p. 510-512; 1992 Linear Accelerator Conference; Ottawa, ON (Canada); 24-28 Aug 1992
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Ronsivalle, C.; Giubileo, G.; Messina, G.; Picardi, L.; Vignati, A.
Proceedings of the 3. European particle accelerator conference. V. 11992
Proceedings of the 3. European particle accelerator conference. V. 11992
AbstractAbstract
[en] In the last years a variable energy (15-100 MeV) racetrack microtron has been built at the ENEA Frascati Center for FEL and neutron spectroscopy applications. The operation of the machine needed the introduction of vertical and horizontal correction coils in each return path. Some new performance measurements of the accelerator are presented. (R.P.) 2 refs.; 3 figs.; 1 tab
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Henke, H. (Technische Univ., Berlin (Germany). Inst. fuer Theoretische Elektrotechnik); Homeyer, H. (Hahn-Meitner-Institut Berlin GmbH (Germany)); Petit-Jean-Genaz, Ch. (eds.); [908 p.]; ISBN 2-86332-114-5; ; 1992; p. 427-428; Editions Frontieres; Paris (France); EPAC 92: 3. European particle accelerator conference; Berlin (Germany); 24-28 Mar 1992
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AbstractAbstract
[en] The structure of the zero-phonon line at 1.53 μ-m in e--irradiated Tl+-doped KCl has been investigated as a function of temperature. The particular color center which originates the discrete phonon structure has not been identified, but it is coupled to a localized mode ℎω = 3.9 meV and possesses a rather small Huang-Rhys factor, S = 1.7. Moreover the narrow absorption structure and the band underneath are essentially stable over a period of almost one year. (Author)
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Giovenale, E.; Doria, A.; Gallerano, G.P.; Letardi, S.; Messina, G.; Ronsivalle, C.; Vignati, A., E-mail: giovenale@frascati.enea.it1999
AbstractAbstract
[en] When a radio-frequency (RF) modulated electron beam passes through a magnetic undulator, coherent emission is produced if the electron bunch length is comparable to the emission wavelength. A method to enhance the coherent spontaneous emission by inducing a proper correlation between the energy and phase distribution of the electrons in the bunch will be presented in this work, together with the design of a device intended to systematically investigate the CSE as a function of the longitudinal phase-space distribution
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S0168900299004866; Copyright (c) 1999 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: Mexico
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Journal Article
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Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment; ISSN 0168-9002; ; CODEN NIMAER; v. 437(1); p. 128-133
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Doria, A.; Asgekar, V.B.; Esposito, D.; Gallerano, G.P.; Giovenale, E.; Messina, G.; Ronsivalle, C., E-mail: gallerano@frascati.enea.it2001
AbstractAbstract
[en] A radio-frequency modulated electron beam passing through a magnetic undulator generates coherent spontaneous emission (CSE) when the electron bunch length is comparable to the FEL resonant wavelength. At long wavelengths, CSE can be significantly enhanced by a proper ramping of the electron energy within the bunch duration, since this allows the contributions of the individual electrons to be added in phase. In this paper, the physical principles of the coherent spontaneous emission are reviewed together with its main experimental features. An accelerating structure, constructed at ENEA-Frascati for the systematic investigation of energy-phase correlation effects, is described together with an analysis of the expected performance
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S0168900201016175; Copyright (c) 2001 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
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Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment; ISSN 0168-9002; ; CODEN NIMAER; v. 475(1-3); p. 296-302
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Doria, A.; Gallerano, G.P.; Giovenale, E.; Messina, G.; Doucas, G.; Kimmitt, M.F.; Andrews, H.L.; Brownell, J.H., E-mail: giovenale@frascati.enea.it2002
AbstractAbstract
[en] Recent measurements at Frascati of the Smith-Purcell radiation emitted from the interaction of a 2.3 MeV (total) electron beam with a 2.5 mm grating show clear evidence of coherent enhancement of the radiation, with power levels exceeding 100 mW at emission angles around 90 deg. relative to the beam direction. The experimental results are in reasonable agreement with theoretical predictions and suggest that Smith-Purcell radiation may offer a simple way of determining the shape and duration of short (picosecond) electron bunches
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S0168900202003248; Copyright (c) 2002 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
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Journal Article
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Numerical Data
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Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment; ISSN 0168-9002; ; CODEN NIMAER; v. 483(1-2); p. 263-267
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Doria, A.; Gallerano, G.P.; Giovenale, E.; Kimmitt, M.F.; Messina, G.; Renieri, A.
Eighteenth international conference on infrared and millimeter waves1993
Eighteenth international conference on infrared and millimeter waves1993
AbstractAbstract
[en] Conventional Free Electron Lasers (FELs) suffer from some drawbacks related to the large size of most electron beam (e-beam) accelerators that implies high costs, system complexity and shielding requirements. In the Far InfraRed (FIR) and Millimeter (MM) wave region the FEL can meet the demand of compactness following several approaches involving the different sub-systems of the device. For example the low e-beam energies required (< 10 MeV) allow the use of small size accelerators like Radio-Frequency (RF) Linacs or Microtrons. The increased performance in terms of gain at wavelengths in the FIR and MM also requires a shorter length of the interaction region, thus allowing the use of short period undulators and small number of periods and resulting in a better efficiency. Following these considerations a compact FEL source in the MM wave range has been realized at ENEA Frascati
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Birch, J.R.; Parker, T.J. (eds.); 714 p; ISBN 0-8194-1392-5; ; 1993; p. 17-18; SPIE--The International Society for Optical Engineering; Bellingham, WA (United States); 18. annual international conference on infrared and millimeter waves; Colchester (United Kingdom); 6-10 Sep 1993; SPIE--The International Society for Optical Engineering, P.O. Box 10, Bellingham, WA 98227-1101 (United States)
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Book
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Conference; Numerical Data
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Baldacchini, G.; Menchini, F.; Montereali, R. M.; Messina, G.; Pace, A.
ENEA, Dipartimento Innovazione, Rome (Italy)2000
ENEA, Dipartimento Innovazione, Rome (Italy)2000
AbstractAbstract
[en] The emission efficiency of F+3 and F2 centers as a function of their concentration has been investigated in LiF crystals colored at RT with 3 MeV electrons. From a careful investigation of their absorption and emission spectra from 80 K to RT, it was discovered that the emission efficiency h of both F+3 and F2 defects is constant up to ∼ 1016 centers/cm3. When increasing the concentration up to 1018 centers/cm3, h is decreasing slightly for the F2 centers and considerably for the F+3 ones. Moreover, the efficiency of the latter centers further decreases by increasing the temperature. A thermally activated process is taking place, while the F2 and other aggregate defects play an important role
[it]
Si e' qui presa in esame l'efficienza quantica di emissione dei centri F+3 e F2 in funzione della loro concentrazione in cristalli di LiF colorati con elettroni da 3 MeV. Dall'analisi degli assorbimenti e delle luminescenze di tali centri, da 80 K a RT, si e' ricavato che la loro efficienza h e' costante fino a concentrazioni di ∼ 1016 centri/cm3, mentre oltre i 1016 centri/cm3 h decresce, leggermente per i centri F2 e sensibilmente per gli F+3. Inoltre, l'efficienza di questi ultimi difetti decresce ulteriormente all'aumentare della temperatura. Si suppone l'esistenza di un processo attivato termicamente, mentre i centri F2 ed altri difetti aggregati svolgono un ruolo importanteSecondary Subject
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2000; 20 p; ISSN 1120-5571;
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Doria, A.; Gallerano, G.P.; Giovenale, E.; Messina, G.; Asgekar, V.B.; Doucas, G.; Kimmitt, M.F.; Brownell, J.H.; Walsh, J.E., E-mail: gallerano@frascati.enea.it2001
AbstractAbstract
[en] We report the first results from an experiment aimed at a detailed study of the interaction of an electron beam with a metallic grating (the Smith-Purcell effect). The electron beam energy was 2.3 MeV (total) and the emitted far infrared radiation was observed at emission angles in the 35-45 deg. range. The observed signal was about 3 orders of magnitude stronger than anticipated by incoherent emission theory
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S0168900201016138; Copyright (c) 2001 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
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Journal Article
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Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment; ISSN 0168-9002; ; CODEN NIMAER; v. 475(1-3); p. 318-322
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AbstractAbstract
[en] The typical problem is addressed of system and process modelling depending on a large number of variables. Demonstration is given that the number of independent variables can be dramatically reduced, by a modified application of Buckingham's theorem of dimensional analysis, resulting in a simplified formulation of the in terms of a limited number of dimensionless arguments. This simplified formulation eventually leads, by interpolation of numerical data, to the derivation of practical approximants to the physical laws governing the system or process. This approach is demonstrated, in case of electron scattering, through a general layer in the elastic regime, as modelled by Monte Carlo methods. In particular, a single dimensionless quality factor is introduced, allowing remarkable simplification both in forward and backward scattering analysis. Hence, Buckingham approximants are derived, effectively describing the scattering by universal laws, applicable to all elements of the periodic table and all variations of electron energy and layer thickness, in the ranges 5 to 150 ke and 1 to 3000nm. The proposed method may be considered as a physical approach to approximation, compared to purely mathematical methods, such as for exmple Pade' approximants. As a consequence, the method is understandably higly effective, and may be extensively applied to all systems and processes susceptible to being described by mathematical modelling
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