Status and Limits of GORIS

DORIS first came into operation in 1973 as a double ring. Later on it was rebuilt as a single ring, and the maximum energy was increased from 3.5 GeV to 5.6 GeV. The experience with the double ring is briefly described, and that with the single ring in more detail. Emphasis is put on those topics which are important for the design of future storage ring colliders, DORIS II is also operating as a source for synchrotron radiation. But this aspect is not treated here, Introduction: The designs of future storage rings for J/Q, Tauand B-Meson physics which would yield a factor of 10 and more luminosity than those operating now are currently being discussed. The attainment of this target will be possible only if all the experience gained from the old rings is transferred to the new ones. The experience with DORIS is described in the following. Some Characteristics of DORIS: The name DORIS originates from double ring storage. When the collider came into operation in 1973, 2 rings were put on top of each other with a crossing in the vertical plane 1) . The idea was to reduce the beam-beam effect by using many (up to 480) low intensity bunches and to avoid unwanted bunch crossings. A further advantage of the double ring scheme was, , that independent control of each beam is possible. Fig. 1 The original DORIS double ring concept A luminosity greater than 1O33 cm" set -' was expected at about 2 GeV. The maximum energy should be 3.5 GeV. However, it turned out very soon, that the maximum tolerable tune shift was only 5, ,009 (instead of the assumed 5 = Z