2X250 GEV GAMMA-GAMMA COLLIDER AT TESLA

This paper presents the conceptual project of a 2 x 250 GeV photon col lider at TESLA. The main idea of the proposal is to use the beam of th e linear collider to generate FEL radiation. At an intermediate phase of acceleration (C = 10 GeV) the electron beam passes the undulator of the FEL amplifier and amplifies the optical radiation of the master o scillator (lambda = 1.053 mu m, peak power 100 MW). An output radiatio n of 350 GW peak power is produced at the amplifier exit. After that t he electron and optical bunches are separated. The electron bunch is a ccelerated up to the final energy of 250 GeV and the optical bunch is transported to the conversion point via an open optical waveguide whic h has the form of a diaphragm focusing line and is placed in parallel with the main accelerator. At the conversion point the optical beam is focused on the electron beam and after the conversion point the gamma quanta follow the initial electron trajectory and meet at the interac tion point with the other gamma-beam produced by another part of the c ollider. The integral luminosity of the colliding gamma-beams is L(gam ma gamma) similar or equal to 1.5 x 10(33) cm(-2)s(-1). The feasibilit y of the proposal is confirmed by the results of numerical simulations .