ESRF Upgrade Programme: Accelerator and X-ray source improvements
The reliability and high performance of the accelerator complex producing the X-ray beams has always been a key element of the ESRF’s success.
Thanks to the Upgrade, the following developments are possible to maintain its capabilities at the forefront:
- An improved beam position diagnostics system, installed in 2009, provides higher beam stability and reduces the vertical emittance to world-record values. An increase of the space available in the straight sections for undulators from five to six metres. This makes possible to install more undulators, notably in a canted set-up to feed two independent end stations in selected straight sections. As of December 2011, ID18, ID30, ID24 and ID20 are equipped with 6 m long narrow aperture vacuum chambers.
- A new RF power source based on semiconductor technology will replace some of the klystron based transmitters. This new RF power source is a more modern and more stable alternative to the aging high power klystron technology. In autumn 2011, a first batch of four 352.2 MHz - 150 kW solid state amplifiers was delivered and after thorough testing connected to the booster cavities. Three more 150 kW amplifiers will later power the cavities of the storage ring.
- Improved RF cavities with higher-order-mode damping to replace the current cavities designed in the 1980s. The new technology will ease the tuning of the machine and enable higher electron beam currents. Three cavities have been ordered from three different suppliers and are currently being tested one by one before their definitive installation during the summer of 2013.
This Upgrade will push the accelerators and X-ray source to limits beyond the most optimistic expectations at the time of their design. Since several years, the ESRF has in parallel looked at the prospect of a new “Ultimate Storage Ring” with a brilliance fifty or one hundred times higher than possible today. Today, these studies focus on a machine to be built in the existing storage ring tunnel, replacing only the curved sections with new ones, within the second phase of the ESRF Upgrade Programme after 2015.