The production of polarized and tagged gamma-ray beams by the backscattering of Laser light on the relativistic electrons circulating in storage rings is discussed. the main characteristic and the experimental results of the Ladon and LEGS beams are presented. The Graal beam is introduced.
Babusci, D 
- Istituto Nazionale di Fisica Nucleare, Frascati (Italy). Lab. Nazionale di Frascati