Production Of Mesons By The 184 Inch Berkeley Cyclotron PDF Download

It is of general interest to make the mesons artificially produced in the 184-inch cyclotron available for general experiments outside the tank. Thus far only photographic techniques have been used in conjunction with the Berkeley meson work. By bringing the beam outside the tank it is hoped that cloud chamber, and possibly counter methods, may be used in meson studies. In addition, the measurement of the lifetime of the [pi] meson appears possible if long meson trajectories are obtained. The method discussed here accomplishes the removal of the mesons from the cyclotron tank by allowing the mesons produced in a thin target struck by the 380 Mev alpha particle beam to enter a region of very weak magnetic field which permits them to leave the tank along a path of weak curvature. The technical problem involved here is, therefore, to produce a magnetic shield which reduces the field of the cyclotron from about 14,000 gauss to about 1,000 gauss, and to place this shield within a very short distance of the circulating beam without disturbing the dynamics of the beam itself.