Coherent X-Ray Generation Via Laser Pumping of a Relativistic Ion Beam - Feasibility Assessment

Abstract

The efficiency of most popular approach to generating short wavelength radiation involving particle beams, FEL1, is limited by the Thomson scattering cross section. If one were to use a beam of particles having a resonant scattering cross section for some frequency, a greatly enhanced gain might be expected. A natural candidate is a hydrogenic positive ion, having Z > 2, with a single bound electron. The fact that the ion is charged allows the beam to be accelerated to relativistic energies (γ≫ 1), therefore one can exploit the properties of relativistic kinematics which dictate that the back scattered radiation will have its wavelength shortened by a factor (2γ)2.