Field and resonance control of superconducting radio frequency (SRF) cavities are often implemented as independent control loops. A control loop for amplitude and phase uses the power amplifier signal as the control signal and a separate loop for resonance control uses a piezo tuner. Traditional proportional-integral (PI) loops are implemented for field control, whereas more elaborate...
In an effort to reduce the power consumption linked to RF operation of the European X-ray free electron laser (EuXFEL), the klystron high voltage is no longer kept constant but shaped to minimize the regulation overhead over the RF pulse. This intra-pulse dynamic change of the high power gain demands an adaptation of the low-level RF drive to stabilize the klystron signal in amplitude (up to a...
In this work, the experimental results obtained with a new type of disturbance rejection algorithm control, the Modified ADRC (MADRC) algorithm applied to a 9-cell tesla-type SRF cavity are presented. The cavity is located in the HobiCat test bench of the Helmholtz-Zentrum Berlin. The main advantage of the MADRC controller is the addition of a new control element for increasing the stability...
China Spallation Neutron Source(CSNS) beam power will upgrade to 500 kW(CSNS-II), energy gain of H- linac will up to 300 MeV from 80 MeV using about 48 superconductor cavities. LLRF is an important device for controlling the amplitude and phase of the SRF cavity field to be less than ± 0.3% and ± 0.3 °, as well as maintaining resonance stability. By the way ,quench detection and similar...
A LLRF cavity control system has been designed in Shanghai High Repetition Rate XFEL and Extreme Light Facility (SHINE) project to ensure its rf field stability. The system employs non-IQ sampling and uses two driven modes in amplitude /phase control, namely, the Self-excited Loop (SEL) and the Generator Driven System (GDR). Additionally, each cavity is tuned with a Piezo actuator and a slow...
