Slow-target accelerators

Usually two regimes of operation of an accelerator are considered: a fixed target mode in which beams of secondary particles such as mesons or neutrinos can be produced and studied; or a collider mode in which two beams are brought into head-on collision. In the latter case ony the particles of the accelerated beams can be studied in interaction. This paper considers an intermediate mode in which a collider might be used as a source of a beam of very heavy exotic particles which could not be made in the low c.m. collisions of fixed target operation. In that case one can recognize the low energy beam of the collider as a slow target and still obtain some of the kinematic advantages of a fixed target machine. It will turn out to be of limited application, to say the least. The asymmetry in the energies of the colliding beams will be made as great as possible, consistent with providing enough energy in the c.m. to provide an adequate production of the desired exotic particle. This clearly enhances the energy and the intensity of the kinematically formed ''beam'' of exotics