On the possibility of constructing a high luminosity 2 × 5 GeV photon collider at SLC

Abstract

Physical principles of the operation of high-energy photon linear colliders (PLC's) based on the Compton backscattering of laser photons on high-energy electrons are discussed. The main emphasis is on analyzing the possibility of constructing a PLC with a center-of-mass energy of 3–10 GeV at the Stanford Linear Collider (SLC). It can be done with minor modifications of the existing facility by installing a new injector, kicker magnet and a two-stage free-electron laser (FEL). The proposed FEL system would consist of a tunable FEL oscillator ( λ ∼ 10–30 μm, output power ∼ 10 MW) with subsequent amplification of the master signal in an FEL amplifier up to a power of ∼ 3 × 10 11W. The FEL parameters are optimized, restrictions on the electron beam and FEL magnetic system parameters are formulated, and the means of possible technical realization are discussed. The FEL-based photon collider at SLC, providing a luminosity of colliding γγ beams L γγ of about 10 34 cm −2 s −1, may be constructed at the present level of acceleration technique R&D. It would be a unique instrument for precise study of charmonium and bottomonium physics as well as τ-lepton physics providing ∼ 10 2 polarized τ leptons per second. At the same time, the Photon Linear Collider at SLC would serve as a reliable test base for constructing future TeV-range photon linear colliders.