Design of Compact Monochromatic Tunable Hard X-Ray Source Based on X-band Linac

Abstract

A compact tunable monochromatic (1 to 10 percent bandwidth rms) hard X-ray source based on laser-electron collisions for medicine is proposed. An X-band linac is introduced to realize a remarkably compact system. We have designed a compact monochromatic tunable hard X-ray source as a demonstration. An X-band (11.424 GHz) linac for the purpose is being manufactured. Numerical considerations using CAIN code and luminosity calculations have been performed to estimate the X-ray yield. An X-band thermionic-cathode RF gun and an RDS (round detuned structure) X-band accelerating structure are applied to generate a 50 MeV electron beam with 20 pC/micro-bunch, 1 µs macro-pulse. The total X-ray yield by laser-electron collision with the electron beam and Q-switch Nd:YAG laser with a pulse intensity of 2 J/10 ns is 10 7 photons/RF-pulse (10 8 photons/s in 10 pps). We will adapt the technique of laser pulse circulating to increase the X-ray yield up to 10 8 photons/pulse (10 9 photons/s). Twenty eight percent of the photons with an energy spread of 10% rms are expected to be available by collimating the scattering angles of X-ray photons.