Vélez, A.V. Glock, H.-W. Goslawski, P. Jankowiak, A. Knobloch, J. Neumann, A. Ries, M. Wüstefeld, G. JACoW Geneva, Switzerland 978-3-95450-178-6 10.18429/JACoW-SRF2015-TUAA03 English 462-466 TUAA03 cavity damping SRF HOM storage-ring Contribution to a conference proceedings 2015 2015-12 http://dx.doi.org/10.18429/JACoW-SRF2015-TUAA03 http://srf2015.vrws.de/papers/tuaa03.pdf CW SRF Cavities have been used very successfully in the past in synchrotron light sources to provide high power acceleration. Here we present a novel application of higher harmonic systems of two frequencies (1.5 GHz and 1.75 GHz) to generate a beating of accelerating voltage. With such a system it is possible to store "standard" (some 10 ps long) and "short" (ps and sub-ps long) pulses simultaneously in the light source. This opens up brand new possibilities for light source users to perform dynamic and high-resolution experiments at the same facility. The demands on the SRF system and RF control are substantial and a new design, based on waveguide damping, is currently being developed. This system will be used for a major upgrade of the BESSY-II facility to the BESSY Variable Pulse Storage Ring (BESSY-VSR) for a next-generation storage-ring light source. We will discuss the concept, challenges and designs for BESSY-VSR.