Twin Orbit operation successfully tested at BESSY II

A synchrotron source point image of a bending magnet of the Twin Orbit modus. The second orbit closes after three revolution and is winding around the standard orbit at the center.

A synchrotron source point image of a bending magnet of the Twin Orbit modus. The second orbit closes after three revolution and is winding around the standard orbit at the center. © HZB

The first “Twin Orbit User Test week” at BESSY II in February 2018 was a big success and can be considered as an important step towards real user operation. Physicists at Helmholtz-Zentrum Berlin have been able to store two separate electron beams in one storage ring. The twin orbit operation mode can serve users with different needs of the time structure of the photon pulses simultaneously and offers elegant options regarding the future project BESSY VSR.

The Twin Orbit operation mode makes use of non-linear beam dynamics and provides two stable well separated orbits for storing two electron beams in one storage ring. The bunch fill patterns of both orbits can be chosen, to some extent, independently, which allows for fulfilling normally incompatible user needs, simultaneously. For example, one orbit can be used to store a homogenous multi bunch fill to deliver high average brilliance for photon hungry experiments, whereas only one single bunch is stored on the other orbit for timing experiments, providing a much lower pulse repetition rate.

First experiments in 2015

It is a long process from an idea to a real operational week, especially at a running multi user facility. First studies of this mode started already 2015 at the smaller ring, the Metrology Light Source (MLS), resulting in a successful user experiment with the Physikalisch Technische Bundesanstalt (PTB) [1]. In parallel a group of HZB experts implemented and optimized this mode at BESSY II in single machine commissioning shifts. Important milestones have been the operation of a large number of insertion devices as well as the topping up injection scheme to keep the stored current constant. In 2017 a successful overnight run with topping up injection and some participating beamlines gave confidence for a first longer test week [2].

Excellent availabilty of synchrotron light

The days of this “Twin Orbit User Test week” have been used for common experiments of machine group and beamline scientists in order to characterize this operational mode and generate feedback for further optimization. During the nights and the complete weekend ‘normal’ user time was scheduled with two different fill patterns (multibunch and single bunch) on both orbits. The availability and stability of the synchrotron source were comparable to the current standard user mode and exceeds/reaches 99 per cent.

Elegant option for BESSY VSR

“There is still a lot of work to do, but nevertheless this proof-of-principle week showed that a development towards a realistic user mode should be possible. And even more, for the future BESSY VSR project, it could be a very elegant way to separate short and long bunches”, Prof. Andreas Jankowiak concludes.

[1] http://accelconf.web.cern.ch/AccelConf/IPAC2015/papers/mopwa021.pdf

[2] http://accelconf.web.cern.ch/AccelConf/ipac2017/papers/wepik057.pdf

 

Dr. Paul Goslawski

You might also be interested in

  • Humboldt Fellow Alexander Gray comes to HZB
    News
    12.08.2022
    Humboldt Fellow Alexander Gray comes to HZB
    Alexander Gray from Temple University in Philadelphia, USA, is working with HZB physicist Florian Kronast to investigate novel 2D quantum materials at BESSY II. With the fellowship from the Alexander von Humboldt Foundation, he can now deepen this cooperation. At BESSY II, he wants to further develop depth-resolved X-ray microscopic and spectroscopic methods in order to investigate 2D quantum materials and devices for new information technologies even more thoroughly.
  • Green hydrogen: Nanostructured nickel silicide shines as a catalyst
    Science Highlight
    11.08.2022
    Green hydrogen: Nanostructured nickel silicide shines as a catalyst
    Electrical energy from wind or sun can be stored as chemical energy in hydrogen, an excellent fuel and energy carrier. The prerequisite for this, however, is efficient electrolysis of water with inexpensive catalysts. For the oxygen evolution reaction at the anode, nanostructured nickel silicide now promises a significant increase in efficiency. This was demonstrated by a group from the HZB, Technical University of Berlin and the Freie Universität Berlin as part of the CatLab research platform with measurements among others at BESSY II.
  • RBB Abendschau on visit at CatLab
    News
    01.08.2022
    RBB Abendschau on visit at CatLab
    CatLab got a visit from the rbb Abendschau.
    Under the title "Der Weg weg vom Erdgas" (The way away from natural gas), the programme was broadcast on Sunday, 31st July in the rbb Abendschau and will be available in the rbb media library for 7 days.