A possible scheme to obtain e/sup -/e/sup -/ and e/sup +/e/sup -/ collisions at energies of hundreds of GeV

As a contribution to the discussion on very long term developments in the field of high energy physics, it is pointed out that it is possible to devise e/sup -/e/sup -/ and e/sup +/e/sup -/ colliding beam machines which are not affected by the large synchrotron losses typical of conventional storage rings. The scheme proposed here makes use of two collinear superconducting linacs which at the same time accelerate and recover the energy fed to the electron and positron beams. (2 refs).