DESY is charged to work on a roadmap for photon science in Germany. This includes an upgrade of PETRA III into a low-emittance storage ring (horizontal emittance well below 50 pmrad) in about 10 years from now that would make undulator radiation at about 1Angström nearly diffraction limited. In preparation the workshop "Science at PETRA IV" is to explore the scientific opportunities of such a source. The workshop will be held on March 23-24, 2015 at DESY to discuss the scientific opportunities provided by such a source. We are very much looking forward to welcoming you on this occasion.
DESY Hamburg
CFEL SemRoom 1+2
Notkestr, 85 22607 Hamburg
Some information of what can be expected from this future source: - The horizontal emittance that can be expected from a MBA storage ring the size of PETRA is < 50 pmrad, which is at least a factor 20 times smaller than that of PETRA III. The vertical emittance (currently about 10 pmrad) will not change much. If the horizontal emittance can be pushed to 10 pmrad, the beam is diffraction limited up to an energy of 10 keV. - The total power in the undulator beam is expected to remain similar to current values. - The time structure of the bunches in the storage ring remains nearly unchanged (maybe slightly longer pulses than today). You can assume a pulse length of the order of 100 ps. - The expected brilliance, however, increases by at least a factor 20 (factor 100 in case of 10 pmrad). - As a consequence, - the coherent flux increases approximately proportionally to the brilliance at high x-ray energies - the whole beam has a high degree of lateral coherence for soft and tender x-rays (lateral coherence length >= beam size). - The coherent flux can be nanofocused to the diffraction limit. Thus, an increase in the nanofocused flux is proportional to the brilliance for the high-energy regime. At low energies, the whole beam can be nanofocused. - For a given focusing optic, the flux density in focus is proportional to the coherent flux. - At high energies (> 30 keV) a significant coherent fraction is expected. This implies that many experiments exploiting the coherence at low x-ray energies today could be carried out at high x-ray energies. You can find further information on DLSRs at: