INCREASING THE ENERGY ACCEPTANCE OF HIGH-BRIGHTNESS SYNCHROTRON LIGHTSTORAGE-RINGS

Brightness is the prominent figure of merit for the present third-gene ration synchrotron light sources. The associated high electron density leads to beam lifetime reduction due to the ''Touschek effect'', espe cially in low-energy machines and in the single-bunch operation mode. For this reason, several low-energy third-generation light sources can not fully exploit their potential to increase brightness by lowering t he coupling between vertical and horizontal emittance without arriving at unacceptably short beam lifetime. The ''Touschek lifetime'' can be increased if the energy acceptance of the synchrotron light storage r ings could be widened beyond the usual value of +/- 2% which is normal ly provided in order to satisfy quantum lifetime requirements. The pre sent article describes the lattice and RF system proposed for the Swis s Light Source project (SLS) that have been further optimized in order to provide energy acceptance of about +/- 6%. The increased energy ac ceptance might also be of interest for high-gain storage-ring-based FE L applications. (C) 1998 Elsevier Science B.V. All rights reserved.