Conveners
Measurements and Calibration: Measurements and Calibration I
- Tomasz Plawski (Jefferson Lab)
Measurements and Calibration: Measurements and Calibration II
- Tim Berenc (Argonne National Laboratory)
Precise measurements of the cavity-loaded quality factor (QL) is crucial for monitoring the performance of superconducting radio-frequency (SRF) cavities. The conventional "field decay method" cannot be used to measure QL accurately when the impedance is mismatched. This can lead to nonzero forward signals (Vf), which significantly affect the measurement accuracy. To address this limitation,...
The linear accelerator of European XFEL exhibits an outstanding phase and amplitude stability using state-of-the-art low-Level RF (LLRF) controls in combination with an optical synchroniation system. The achieved RF field regulation precision is well within design criteria, chosen to reach an electron bunch arrival time stability on the 10fs rms level. However, the high complexitiy of the...
Based on beam-induced transients observed in open loop, cavity gradients are routinely calibrated at the FLASH and European XFEL accelerators. The method used to perform this beam-based calibration, its accuracy and limitation are presented. The tools developed over the years to support and automate this task are also presented.
The Proton Synchrotron Booster (PSB) produces a variety of proton beams covering a very large longitudinal parameter space, which are accelerated up to 2 GeV. This low-energy regime requires a significant frequency sweep of the RF system. Finemet-based cavities provide this large frequency range without the need of a tuning loop, but they introduce a significant longitudinal broadband...
The traditional method for determining the synchronous phase (SP) of beam typically relies on “phase scan method”. Despite its high precision and reliability, this method requires a significant amount of runtime. Processes such as phase drift caused by environmental disturbances or rapid recovery after cavity faults (such as Quench) necessitate repeated execution of the phase scan procedure....
In this contribution, we describe the advantages of the pilot tone compensation technique that we have implemented in a new BPM system for Elettra 2.0. The injection of a fixed reference tone upstream of the cables allows for a continuous calibration of the system, compensating for the different behaviour of each channel due to thermal drifts, variations in cable characteristics, mismatches...
In recent years, we witnessed an increasing interest in the search of light Dark Matter (DM), addressing in particular axions. Axion existence would untie the long-standing DM problem. Its cosmological evolution and astrophysical constraints indicate a favorable mass range between 1 μeV < ma < 10 meV.
The axion observation technique is based upon its inverse Primakoff conversion into one...