Operation with a Low Emittance Optics at Anka

The electron storage ring at ANKA is designed as a variation of an eightfold DBA structure. Since its commissioning the facility has been operated with zero dispersion in the long straight sections resulting in an emittance of about 100 nmrad. Since mid 2004 ANKA is operated with dispersion distributed over the complete ring thus reducing the emittance to 50 nmrad. Optics calculations and measurements as well as operational experience will be discussed. In order to reduce the losses due to Touschek scattering, a lengthening of the bunches was done by modulation of the main frequency with twice the synchroton frequency. An increase of the lifetime by 5 h could be achieved.