FLASH Beam-Off RF Measurements and Analyses

TL;DR

This paper presents measurements and analysis of RF stability in the FLASH accelerator's cryomodules, providing insights relevant to the design and operation of future linear colliders like the ILC.

Contribution

It offers detailed waveform data and analysis procedures for RF stability, perturbations, and overhead in superconducting cryomodules, advancing understanding for linear collider RF systems.

Findings

RF input and cavity field stability characterized

Perturbations to superconducting cavity frequencies analyzed

RF overhead requirements for constant gradient determined

Abstract

The FLASH L-band (1.3 GHz) superconducting accelerator facility at DESY has a Low Level RF (LLRF) system that is similar to that envisioned for ILC. This system has extensive monitoring capability and was used to gather performance data relevant to ILC. In particular, waveform data were recorded with beam off for three, 8-cavity cryomodules to evaluate the input rf stability, perturbations to the SC cavity frequencies and the rf overhead required to achieve constant gradient during the 800 microseconds pulses. In this paper, we discuss the measurements and data analysis procedures and present key findings on the pulse-to-pulse input rf and cavity field stability.