Ultra-bright X-ray and gamma sources by Compton backscattering of CO2 laser beams

A picosecond laser interacting with a relativistic electron beam behaves like a virtual wiggler of an extremely short period equal to half of the laser wavelength. This approach opens a route to compact, high-brightness laser synchrotron sources (LSS). We discuss how the emerging terawatt picosecond CO2 laser technology facilitates achieving the ultra-high peak flux and brightness desirable for LSS applications in science and technology. The first laser of this class is under development at the BNL Accelerator Test Facility (ATF). Together with the high-brightness 50 MeV electron beam available at the ATF, this laser will be used for a prototype LSS demonstration. Flashes of collimated 4.7 keV (2.6 Angstrom) X-rays of 3 ps pulse duration, with a flux of similar to 10(22) photons/s, may be produced via linear Compton backscattering. This is several orders of magnitude above the peak numbers attained by the conventional synchrotron sources. Exploiting the promising approach to a high-gradient laser wakefield accelerator, a "table-top" wakefield gamma LSS may become feasible in the near future. The prospective gamma-gamma and e(+/-)-gamma colliders in the TeV energy range are among the advanced applications of picosecond CO2 laser technology. (C) 1998 Elsevier Science B.V. All rights reserved.