C - LLRF Control Systems and Beam Diagnostics

LLRF Control Systems and Beam Diagnostics

The realization of an ERL operation mode includes challenging requirements on the rf-system and requires new concepts in beam diagnostics. A LLRF system topology design needs to be based on the physical requirements and the available signals, considering phase and amplitude accuracy, the reduction of microphonic effects and the handling of beam loading including beam current variation and imbalances. High beam power and the 180° phase shift between accelerating and decelerating bunches resulting in a change of bunch spacings between ERL and conventional mode, which is even worse in case of non-isochronous operation since the phase shift is not exactly 180° anymore, complicates the use of conventional beam diagnostics like e.g. rf-monitor devices. Project Area C of AccelencE addresses the challenges of developing and adapting both LLRF control systems and beam diagnostics for ERL operation.

Research topics

  • Strahldynamik und -diagnose am Energie-rückgewinnenden S-DALINAC

    Beam Diagnostics at the Energy-Recovering S-DALINAC

    This project connects investigations of the beam dynamics of the S-DALINAC with new beam diagnostics, which is needed to verify the simulations. The beam dynamics studies consist of simulations of the beam transport, which are used to determine suitable accelerator setpoints. Furthermore, the phenomenon of transverse beam breakup is studied in order to understand the dependence of the maxium possible beam current of the beam energy and the S-DALINAC operation mode. Finally, the beam diagnostics are being extended by the addition of several emittance measurement stations based on optical transition radiation. The emittance measurements allow to make sure that the beam dynamics simulations are based on appropriate starting conditions and describe the beam transport properly.

    Author: M.Sc. Jonas Pforr

    Supervisors: Prof. Dr. Dr. h.c. mult. Norbert Pietralla, JProf. Dr. Florian Hug

  • Entwicklung einer ERL-Strahldiagnose und Untersuchungen zur Stabilität des ERL-Betriebs am S-DALINAC (Match)

    Development of an ERL beam diagnosis and studies on the stability of ERL operation at the S-DALINAC (match)

    The aim of this project is to develop a 6 GHz cavity beam position monitor for the multi-turn ERL operation. With this monitor, the simultaneous position measurement of both the accelerated and the decelerated beam is envisaged. Investigations of the stabilities and tolerances of the magnetic fields and the RF control are carried out by simulating the transversal and longitudinal beam dynamics in ERL mode.

    Author: M.Sc. Manuel Dutine

    Supervisors: Prof. Dr. Dr. h.c. mult. Norbert Pietralla, Prof. Dr. Joachim Enders

  • Weiterentwicklung des digitalen LLRF-Systemsam S-DALINAC für stabilen ERL-Betrieb

    Enhancing the S-DALINAC digital LLRF control system for stable ERL operation

    The digital LLRF system currently in use at the S-DALINAC has been in service since 2012. A major Upgrade of the accelerator from its twofold to a threefold recirculation layout in 2016 enabled its use as an Energy Recovery Linac (ERL), for what the LLRF system had not been designed. The aim of this project includes on the one hand an behavior analysis of the current LLRF system during ERL operation and on the other hand a focus on the optimization of beam quality through additional feedback loops. In addition to measurements, beam dynamics simulations on the effect of RF modulation errors are undertaken in order to investigate electron beam stability.

    Author: M.Sc. Manuel Steinhorst

    Supervisors: Prof. Dr. Dr. h.c. mult. Norbert Pietralla, Prof. Dr. Harald Klingbeil

  • Digitale Open-Loop & Closed-Loop HF-Steuerung für supraleitende Kavitäten in ERLs

    Digital open-loop & closed-loop RF control for superconducting cavities in ERLs

    The aim of this project is the development of a generic RF control system that is capable of running in a “common” multi-turn accelerator mode as well as in energy-recovering mode. Research and Development of a newly designed low-level RF system begins with collecting the requirements, modelling and understanding the systems' behavior and system identification procedures before an appropriate control system topology can be chosen. Afterwards, the control system design begins, including modern signal processing techniques and further optimization with more sophisticated controllers.

    Author: Sebastian Orth

    Supervisors: Prof. Dr. Harald Klingbeil, Prof. Dr. Dr. h.c. mult. Norbert Pietralla

  • Design, Installation und Inbetriebnahme einer neuen Ausleseelektronik für HADES ECAL und Diamant-Detektoren für TO-Rekonstruktion und Strahldiagnose

    Design, Installation and Commissioning of a new read-out electronics for HADES ECAL and diamond detectors for TO-reconstruction and beam diagnostics

    Author: M.Sc. Adrian Rost

    Supervisors: Prof. Dr. Tetyana Galatyuk, JProf. Dr. Florian Hug

  • Installation und Inbetriebnahme der verbesserten Einfangssektion des S-DALINAC Injektors

    Installation and comissioning of the improved capture section for the S-DALINAC injector

    For the installation of the new superconducting capture structure designed in the project of D. Bazyl, the first module of the superconducting part of the S-DALINAC injector has to be modified. The tuner frame and other surrounding parts of the cavity have to be adapted to the new geometry of the capture structure in order to prepare the module for the upcoming upgrade. Furthermore, the beam dynamics of the bunched electron beam have to be studied: A diagnostic setup at the end of the normal conducting injector is being planned to characterize the thermionic gun beam parameters in detail, which contributes to a successful commissioning of the new capture section. This project includes the preparation, installation and commissioning of the upgraded injector section and corresponding diagnostics which will contribute to an improved beam quality of the S-DALINAC.

    Currently, a state funded capture cavity with β = 0,86 is under construction at Research Instruments (RI).

    Author: M.Sc. Simon Weih

    Supervisors: Prof. Dr. Joachim Enders, Prof. Dr. Dr. h.c. mult. Norbert Pietralla

  • Strahlstabilität und Stabilisierungsaspekte am MESA (Match)

    Beam stability and stabilization aspects of MESA (match)

    Author: M.Sc. Pascal Klag

    Supervisor: Prof. Dr. Frank Maas

  • Entwicklung von Elektronik zur Detektorauslese für das P2-Experiments am MESA

    Development of detector read-out electronics for the P2 experiment at MESA

    The MESA accelerator is planned to be built in the next years at the Institute for Nuclear Physics in Mainz. The P2 experiment planned at this new machine aims to measure the parity-violating asymmetry of elastic electron-proton scattering with never before achieved high precision. Many technical challenges have to be solved to reach such high precision. In order to measure asymmetries in the order of 10⁻⁹, the front-end signal path has to be well-planned. The helicity of the polarized electron beam will be flipped with a rate of 2 kHz, so the bandwidth of the signal path and the sampling rate of the ADC need to be adjusted accordingly. Within the scope of this project, a joint read-out electronics for the P2 experiment and for Møller experiments at Jefferson Lab isbeing developed together with collaborators from the University of Manitoba.

    Author: M.Sc. Rahima Krini

    Supervisor: Prof. Dr. Frank Maas

  • Strahlpositionsstabilisierung für das P2-Experiment am MESA (Match)

    Beam position stabilization for the P2 experiment at MESA (match)

    Author: Dipl.-Phys. Ruth Kempf

    Supervisors: Prof. Dr. Kurt Aulenbacher, Dr. Marco Dehn

  • Entwicklung eines auf Methoden der künstlichen Intelligenz basierten Kontrollsystems am S-DALINAC

    Development of a control system based on artifical intelligence methods at the S-DALINAC

    For the EPICS-based control system of the superconducting electron linear accelerator in Darmstadt S-DALINAC, extensions based on AI-methods are currently under developement. One task is to assist with the beam setup and control with artificial neural networks using reinforcement learning. A particle accelerator has a very large set of parameters with often hidden relationships between them. Therefor neural networks are a suited instrument to use. Different neural network structures and their training with reinforcement learning are currently tested with simulations. Another purpose for the control system extension is to find relationships between parameters from our cryo-plant. This will be used to create a supervising tool to predict and prevent possible malfunctions with the help of data-mining algorithms.

    Author: M.Sc. Jan Hauke Hanten

    Supervisors: Prof. Dr. Dr. h.c. mult. Norbert Pietralla, Prof. Dr. Joachim Enders