New Developments at Petra

Installation of "mini-ß-inserts", addition of 2nd harmonic cavities , and increase of energy are the main efforts at PETRA now. By reducing the free space for the high energy physics detectors to ± 4.45 m the beta-functions at the interaction points can be decreased to 6 cm vertically and 130 cm horizontally, thus decreasing the beam size by a factor of 2.5. First results of operation are presented. Theory and some experimental evidence show that with the help of 2nd harmonic cavities (1 GHz) both a vertical single bunch instability and synchro-betatron resonances can be cured. The 1 GHz system under construction will be able to reduce the longitudinal focusing in the bucket center to zero up to 11 GeV particle energy. In order to increase the maximum PETRA energy fur luminosity runs from 36.7 GeV to 41.4 GeV and later on to 45.0 GeV, the 500 MHz rf system will be extended. First, the number of rf-transmitters will be doubled, and in a second step additional new type seven-cell cavities will be installed.