Theoretical estimation and experimental design of high-intensity far-infrared to MM-wave coherent synchrotron radiation generated by short electron bunches at BFEL

Broadband continuous and high-intensity coherent synchrotron radiation (CSR ) emitted from 4 ps electron bunches provided by the 30 MeV RF linac of Bei jing FEL is analyzed and numerically calculated using an exact series expan sion for the infinite integral of fractional modified Bessel function. CSR in the mm-wave and far-IR to mm-wave regions can be respectively generated by directly using these bunches and by applying those ones compressed to le ss than or equal to = 1 ps. The CSR powers, approximately as 10(8)-10(9) ti mes as the SR ones, in the range from several hundred microwatts to milliwa tts are dependent on chosen electron density distribution, wavelength range , and gathering angle. The power produced by rectangular bunches is greater than that generated by Gaussian ones. The shorter the bunch, the stronger the produced CSR, the greater the energy concentrated to the far-IR end. Ex periments to generate CSR and measure the bunch length are designed. (C) 20 00 Elsevier Science B.V. All rights reserved.