CALCULATIONS OF SMITH-PURCELL RADIATION GENERATED BY ELECTRONS OF 1-100 MEV

Smith-Purcell radiation is produced when a charged particle moves clos e to a conducting grating. Recent experiments using electrons of 3.6 M eV have demonstrated the potential use of this effect as a strong tuna ble radiation source in the infrared spectral range. Large intensities can be expected using high-energy electrons but apparently no detaile d calculations have been published until now for this energy domain. W e have calculated spectra of Smith-Purcell radiation generated by 1-10 0-MeV electrons using the integral method, which is of general validit y for any type of grating profile, and using the modal expansion metho d and the improved point-matching method for lamellar and sinusoidal g ratings, respectively. The calculations are restricted to perfectly co nducting surfaces and to electron trajectories perpendicular to the gr ating rulings. Some problems related to an extension of the model to i nclude finite electrical conductivity (as needed for calculations of S mith-Purcell radiation in the uv and x-ray spectral range) and for arb itrary tilting angles of the electron beam with respect to the grating are discussed.