Publications

J. Kaiser1, C. Xu2, A. Eichler1, A. Santamaria Garcia2, O. Stein1, E. Bründermann2, W. Kuropka1, H. Dinter1, F. Mayet1, T. Vinatier1, F. Burkart1, H. Schlarb1 1Deutsches Elektronen-Synchrotron DESY, 2 Karlsruhe Institute of Technology KIT arXiv Abstract Online tuning of real-world plants is a complex optimisation problem that continues to require manual intervention by experienced human operators. Autonomous tuning is a rapidly expanding field of research, where learning-based methods, such as Reinforcement Learning-trained Optimisation (RLO) and Bayesian optimisation (BO), hold great promise for achieving outstanding plant performance and reducing tuning times....

X. Chen, X. Qi, C. Su, Y. He, Z. Wang, K. Sun, C. Jin, W. Chen, S. Liu, X. Zhao, D. Jia, M. Yi Chinese Academy of Sciences arXiv Abstract The superconducting linear accelerator is a highly flexiable facility for modern scientific discoveries, necessitating weekly reconfiguration and tuning. Accordingly, minimizing setup time proves essential in affording users with ample experimental time. We propose a trend-based soft actor-critic(TBSAC) beam control method with strong robustness, allowing the agents to be trained in a simulated environment and applied to the real accelerator directly with zero-shot....

** Simon Hirlaender, Lukas Lamminger, Giovanni Zevi Della Porta, Verena Kain** Abstract Reinforcement learning (RL) is a promising direction in machine learning for the control and optimisation of particle accelerators since it learns directly from experience without needing a model a-priori. However, RL generally suffers from low sample efficiency and thus training from scracth on the machine is often not an option. RL agents are usually trained or pre-tuned on simulators and then transferred to the real environment....

F. M. Velotti1, B. Goddard1, V. Kain1, R. Ramjiawan1, G. Z. Della Porta1 and S. Hirlaender2 1CERN, 2University of Salzburg Machine Learning: Science and Technology Abstract To improve the performance-critical stability and brightness of the electron bunch at injection into the proton-driven plasma wakefield at the AWAKE CERN experiment, automation approaches based on unsupervised machine learning (ML) were developed and deployed. Numerical optimisers were tested together with different model-free reinforcement learning (RL) agents....

X. Chen, Y. Jia, X. Qi, Z. Wang, Y. He Chinese Academy of Sciences Physical Review Accelerators and Beams Abstract Recently, reinforcement learning (RL) algorithms have been applied to a wide range of control problems in accelerator commissioning. In order to achieve efficient and fast control, these algorithms need to be highly efficient, so as to minimize the online training time. In this paper, we incorporated the beam position monitor trend into the observation space of the twin delayed deep deterministic policy gradient (TD3) algorithm and trained two different structure agents, one based on physical prior knowledge and the other using the original TD3 network architecture....

D. Meier1, L. V. Ramirez1, J. Völker1, J. Viefhaus1, B. Sick2, G. Hartmann1 1Helmholtz-Zentrum Berlin, 2University of Kassel Physical Review Accelerators and Beams Abstract Superconducting photoelectron injectors are promising for generating highly brilliant pulsed electron beams with high repetition rates and low emittances. Experiments such as ultrafast electron diffraction, experiments at the Terahertz scale, and energy recovery linac applications require such properties. However, optimizing the beam properties is challenging due to the high number of possible machine parameter combinations....

L. Grech1, G. Valentino1, D. Alves2 and Simon Hirlaender3 1University of Malta, 2CERN, 3University of Salzburg Frontiers in Physics Abstract The Beam-Based Feedback System (BBFS) was primarily responsible for correcting the beam energy, orbit and tune in the CERN Large Hadron Collider (LHC). A major code renovation of the BBFS was planned and carried out during the LHC Long Shutdown 2 (LS2). This work consists of an explorative study to solve a beam-based control problem, the tune feedback (QFB), utilising state-of-the-art Reinforcement Learning (RL)....

J. Kaiser, O. Stein, A. Eichler Deutsches Elektronen-Synchrotron DESY 39th International Conference on Machine Learning Abstract In recent work, it has been shown that reinforcement learning (RL) is capable of solving a variety of problems at sometimes super-human performance levels. But despite continued advances in the field, applying RL to complex real-world control and optimisation problems has proven difficult. In this contribution, we demonstrate how to successfully apply RL to the optimisation of a highly complex real-world machine – specifically a linear particle accelerator – in an only partially observable setting and without requiring training on the real machine....

N. Madysa, V. Kain, R. Alemany Fernandez, N. Biancacci, B. Goddard, F. M. Velotti CERN 13th Particle Accelerator Conference Abstract High intensities in the Low Energy Ion Ring (LEIR) at CERN are achieved by stacking several multi-turn injec- tions from the pre-accelerator Linac3. Up to seven consec- utive 200 μs long, 200 ms spaced pulses are injected from Linac3 into LEIR. Two inclined septa, one magnetic and one electrostatic, combined with a collapsing horizontal or- bit bump allows a 6-D phase space painting via a linearly ramped mean momentum along the Linac3 pulse and in- jection at high dispersion....

T. Boltz Karlsruhe Insitute of Technology KIT PhD thesis Abstract At the time this thesis is written, the world finds itself amidst and partly in the process of recovering from the COVID-19 pandemic caused by the SARS-Cov-2 virus. One major contribution to the worldwide efforts of bringing this pandemic to an end are the vaccines developed by different research teams all around the globe. Produced in a remarkably short time frame, a crucial first step for the discovery of these vaccines was mapping out the atomic structure of the proteins making up the virus and their interactions....