Two photon physics with heavy-ion collisions and photons produced by channeled electrons

Photon-Photon physics at very high energies offers interesting possibilities. One can search for new particles, both for expected ones like the top quark or the higgs particle, as well as exotic ones like supersymmetric particles. It might also be possible to determine important properties of known particles like e.g. the anomalous magnetic moment of the W boson. To do such experiments one needs photons in the 100 GeV range. We investigated two potential sources for such hard photons, namely the equivalent photons of heavy ion collisions and the photons produced in high-energy channeling. (orig.)