Can coherent Smith–Purcell radiation be used to determine the shape of an electron bunch?

ENEA, INN-FIS, Via Enrico Fermi 45, Divisione Fisica Applicata, P.O. Box, 65 I–00044 Frascati (Roma), Italy; Particle Physics Laboratory, University of Oxford, Oxford, UK OX1 3RH; Department of Physics, University of Essex, Colchester, UK CO4 3SQ; Department of Physics & Astronomy, Dartmouth College, Hanover, NH 03755-3528, USA
Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment (Impact Factor: 1.14). 01/2002; DOI: 10.1016/S0168-9002(02)00324-8

ABSTRACT 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° 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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    ABSTRACT: Coherent Smith-Purcell radiation generated by bunched electron beam in the lamellar metal and dielectric gratings in the millimeter wavelength range was compared theoretically and experimentally. For theoretical estimation a simple model suitable for both dielectric and metal gratings was developed. Experimental comparison was carried out using extracted bunched 6.1 MeV electron beam of the microtron at Nuclear Physics Institute (Tomsk Polytechnic University). Both theoretical estimations and experimental data showed the difference of the radiation characteristics from the lamellar metal and dielectric gratings. The radiation from the dielectric grating had peak structure not monotonic one and was more intense comparing with metal grating radiation in the wavelength less than coherent threshold. These differences may be useful for research and development of new compact monochromatic radiation sources in sub-THz and THz region.
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    ABSTRACT: Radiation of a charged particle moving parallel to a inhomogeneous surface is considered. Within a single formalism periodic and random gratings are examined. For the periodically inhomogeneous surface we derive new expressions for the dispersion relation and the spectral-angular intensity. In particular, for a given observation direction two wavelengths are emitted instead of one wavelength of the standard Smith-Purcell effect. For a rough surface we show that the main contribution to the radiation intensity is given by surface polaritons induced on the interface between two media. These polaritons are multiply scattered on the roughness of surface and convert into real photons. The spectral-angular intensity is calculated and its dependence on different parameters is revealed. Comment: 6 pages, 2 figures, submitted to Phys. Rev. ST Accel. Beams
    Review of Modern Physics 05/2010; · 44.98 Impact Factor
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    ABSTRACT: A novel Smith—Purcell (S—P) free electron laser composed of an electron gun, a semi-elliptical resonator, a metallic reflecting grating and a collector, is presented for the first time. This paper studies the characteristics of this device by theoretical analysis and particle-in-cell simulation method. Results indicate that tunable coherent S—P radiation with a high output peak power at millimeter wavelengths can be generated by adjusting the length of the grating period, or adjusting the voltage of the electron beam. The present scheme has the following advantages: the semi-elliptical resonator can reflect all radiation with the emission angle θ and random azimuthal angles, back onto the electron beam with same-phase and causes the electrons to be modulated, so the output power and efficiency are improved.
    Chinese Physics B 05/2011; 20(5):050702. · 1.15 Impact Factor

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