Accelerator Science and Technology Seminar

Titel:

"Design Strategies Towards A Lattice For BESSY III"

Abstract:

Lattice design is a bit like "looking for the needle in the haystack". We need to optimize many lattice properties, like the emittance, the momentum compaction factor, energy acceptance, dynamic aperture, lifetimes, circumference and the like, by varying many tens of magnet parameters and distances, multi-parameter optimization in a very high dimensional space. In the special case of modern Multi-bend Achromat lattices, HZB developed a deterministic approach to lattice design, that enables an understanding of the functionality of different lattice components. The successive set up of the linear lattice can help to prepare a good non-linear behavior. Different lattice options are compared and current aspects of the lattice development are discussed.

Titel:

"Optimising the Non-Linear Kicker Injection using Reinforcement Learning"

Abstract:

Synchrotron light source storage rings aim to maintain a continuous beam current without observable beam motion during injection. One element that paves the way to this target is the non-linear kicker (NLK). The field distribution it generates poses challenges for optimising the topping-up operation.

Within this study, a reinforcement learning agent was developed and trained to optimise the NLK operation parameters. We present a brief introduction to reinforcement learning, the models employed, the optimisation process, and the achieved results.

Titel:

"Characterization of superconductors for SRF accelerators beyond the limits of niobium"

Abstract:

Superconducting radio-frequency (SRF) cavities are a key component for various state-of-the-art particle accelerators. Typically, those cavities are made from niobium for which production techniques and surface treatments have been optimized over many years, providing performances close to the material’s fundamental limits. Thin film coatings are expected to enable operation beyond these limits, i.e. at higher temperature and potentially also at higher accelerating gradients. Especially when aiming for CW applications, the management of dynamic RF losses is crucial, which is closely connected to the quality factor, determined by the cavity’s shape and the material’s surface resistance. Hence, systematic studies on alternative materials and coating processes require measurements of the surface resistance on samples.

Operating a Quadrupole Resonator (QPR), HZB has a world-wide leading role in characterizing superconducting samples at radio frequencies. The QPR enables surface resistance measurements in a wide range of temperature, RF field and frequency along with studies of penetration depth and RF quench field. Recent developments of the sample chamber boosted the measurement accuracy considerably and enabled frequency-dependent studies of the residual resistance. Complementary to that, a simplified measurement device with high sample throughput (RaSTA) is currently under development. Combining those capabilities will enable iterative optimizations of coating processes for high performance SRF thin films.

Titel:

"PM-QP Magnets for BESSY III (A short story of magnet development)"

Abstract:

Permanent Hybrid Magnets are a key technology for particle accelerators to reduce the running costs and with this also the lifetime carbon footprint of new large facilities. Main part of those magnets are Permanent magnet (PM) blocks inside an iron yoke that guides the magnetic flux and defining the final magnetic field distribution. For the magnet optimization the shape, position and material parameters of PMs and yoke have to be adjusted correctly to fulfill focusing or bending parameters, as well as necessary field quality.  For this process a deterministic approach is used to minimize unwanted multipole field distributions in the magnet pole tip region and to increase the efficiency of the magnets. In a second step further parts can be used like iron and thermal shims, as well as electrical or mechanical tuners to implement higher thermal and magnetic stability in the design or to handle small magnetic variations of the real PM blocks.
In this talk, an overview of stepwise magnet optimization and PM technologies will be presented.

Titel:

''ARES: Past, Present and Future''

Abstract: 

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