LLRF Topical Workshop on Advanced Feedback Control (TWoAFC)

Session

System Identification

Oct 15, 2026, 3:15 PM

Nova Gorica, Slovenia

28. Environmental Noise and Disturbance Effects for high-Q SRF Systems

Joshua Einstein-Curtis (Deutsches Elektronen-Synchrotron DESY)

10/15/26, 3:15 PM

System Identification

Oral

Noise and systematic disturbances are important to characterize when working with low-bandwidth SRF cavities that require tight RF regulation. For a future upgrade at XFEL, we have been investigating the microphonics and noise performance of the tunnel, cryomodule, and RF environment in order to better characterize the expected performance, control, and mitigations needed for the design.

19. Mechanical-Mode System Identification for Superconducting Cavities: Grey-Box and Closed-Loop Chirp Methods

Yilin Miao (Institute of Modern Physics, Chinese Academy of Sciences)

10/15/26, 4:25 PM

System Identification

Oral

Mechanical-mode characterization is essential for understanding Lorentz-force detuning (LFD) and improving field stability in superconducting RF cavities. This work presents two complementary approaches for identifying LFD-induced mechanical dynamics under LLRF control. First, a physics-informed grey-box model is estimated from LFD transients. It extracts dominant mechanical modes when...

20. Loop Delay Identification in LLRF Systems via Self-Excited Loop Control

Zhiyuan Zhang (Institute of Advanced Light Source Facilities, Shenzhen)

10/15/26, 4:55 PM

System Identification

Oral

LLRF systems typically employ the classical PI control algorithm to maintain constant cavity voltage and phase. The performance of PI control depends on the design and optimization of the proportional (kp) and integral (ki) parameters; therefore, accurate modeling of the closed-loop path is of great importance. Loop delay is a critical parameter of the closed-loop system, as it determines the...

26. Performance Comparison of Linear vs. Unscented Kalman Filter-Based Gun Detuning Estimation with a Focus on Parameter Identification

Max Herrmann (DESY)

10/15/26, 5:25 PM

System Identification

Oral

The interpulse control laws for the European XFEL's normal-conducting 1.3 GHz gun (rev. 5.2) require detuning measurements to modulate pulse width and phase. However, due to thermal inertia and the inability to place temperature sensors directly on the gun's inner wall, such measurements cannot be obtained directly. This paper compares the tracking performance of two RF-based detuning...