The beamline is called PM4. As a dipole beamline, it provides a moderate photon flux over a wide range of photon energies, in our case in the vacuum ultraviolet/soft X-ray regime. It serves the fixed end-station called LowDosePES. As the name suggests, its specialty is photoemission spectroscopy (PES) at low X-ray dose. Read More →
Each beamline at BESSY II has a dedicated beamline scientist. But who are they? In this little series you are going to find out.Read More →
by Jonas Böhm The last finishing touches are being made to the cryogenic undulator CPMU-17 before it will be installed in the BESSY II storage ring next week. A good moment to look back. The long way of undulators: 70 years old and still up-to-date Home of the first undulator was Stanford. Its linear accelerator (you can see its tunnel in the image) is claimed to be “the world’s most straight object”. In 1952, the Austrian scientist Hans Motz and his team conducted the first experiment, in which a 100-Mev electron beam from the Stanford linear accelerator passed through the undulator. Light radiated by the beam wasRead More →
by Katharina Kolatzki With the new cryogenic undulator CPMU-17 being installed into the BESSY II storage ring, I thought it a good moment to get everyone who may not be that familiar with this essential part of the synchrotron up to speed. What is an Undulator? By now, you might have noticed that undulators are pretty cool things (even the room temperature devices) that are an essential part of synchrotron sources such as BESSY II. In order to understand a little bit more about them, here is a brief introduction to undulators. Synchrotron sources provide especially brilliant light that can be used to examine aRead More →
If you try to search for “PSO” abbreviation in wiki you may find Pacific Symphony Orchestra or Phase-shift oscillator. However, my project at HZB is about neither music nor electricity, but mathematics. For almost a month here I have been working on an algorithm called Particle Swarm Optimization method and I would like you to have some impression of it. Optimization Actually, the definition of optimization problem is quite simple. One has a function of n-variables f(x1, …, xn) and seeks to find such values of variables that give minimum to the function. However, the solution is not that simple, because in general you cannotRead More →