OPERATION AND RECENT DEVELOPMENT AT THE ESRF

We report on the performances achieved by the ESRF storage ring as well as developments accomplished or underway. A new hybrid filling mode based on groups of bunches and a 4-bunch filling pattern are now delivered to the users. Following the increasing demand of users for beam stability, the fast global orbit feedback has been upgraded. The installation of 5 m-long, 8 mm vertical aperture NEG coated aluminium chambers is progressing at a rate of one chamber per shutdown. The increase in current from 200 to 300 mA is being prepared; however, operation in this mode is still impaired by HOM driven longitudinal instabilities. To overcome this difficulty, a longitudinal feedback is being commissioned. HOM damped cavities are also under study to possibly replace the existing five-cell cavities. The policy of preventive maintenance has been continued. Despite this policy, in 2005 the machine availability was slightly affected by water leaks occurring on front-end X-ray absorbers and on one dipole crotch absorber.