Wednesday, October 5, 2022, 4:00 pm

Hosted by: Bjoern Schenke

Since the first observation of synchrotron radiation in 1947, synchrotron light sources have progressed from being perceived as a side effect in operations of high energy colliders to fully dedicated storage rings for research in a wide range of scientific applications. A synchrotron light source is a large complex facility that circulates an electron beam around a ring with straight sections for wigglers and undulators. These devices wiggle the electron beam, resulting in the emission of high-brightness photon beams. Bright photon beams have become important tools for a large number of researchers from academia and industry, fostering rapid growth in scientific discoveries. Further discoveries require the advancing of the photon beam via a dramatic increase of its brightness and coherence. Advancing brightness and coherence of photon beams will open new exciting horizons in the synchrotron sciences. National Synchrotron Light Source II (NSLS-II) at Brookhaven National Laboratory is one of the most advanced synchrotron light sources in the world. I am privileged to be a part of this successful project since the design stage. A highlight of my career at Brookhaven was the NSLS-II accelerator commissioning that began in 2014. In the years since, we have successfully achieved key milestones in optimizing the design performance of NSLS-II, including high photon beam intensity, the lowest horizontal emittance among third-generation light sources, and diffraction-limited vertical emittance. These are crucial parameters to reach high-brightness photons for beamline users. My colleagues and I also made a significant effort in developing new tools and building modern instruments to monitor and improve beam quality. As a result, we have advanced NSLS-II to highly reliable and stable beams to support 28 beamlines in operation, with more planned or under construction.Having accomplished these performance milestones at NSLS-II, we are looking forward to upgrading the existing facility to a new generation synchrotron light source. The goals are an increase in brightness by more than an order of magnitude and full coherence. Diffraction of the photon beam ultimately sets the required value of the electron beam emittance, approaching the diffraction limit in the X-ray wavelength range. To achieve these goals, my colleagues and I invented a novel accelerator concept, known as a "complex bend" magnet, to obtain a dramatically lower emittance and to provide additional space for longer undulators in the ring lattice. This invention would lead to a factor of 50 increase in brightness, which, once realized, would make the upgraded NSLS-II one of the brightest light sources in the world for the next decade and beyond. https://bnl.zoomgov.com/j/1616036512?pwd=OXlqVkI2amNCSWcvM2IvdUdaWlh2dz09