Commissioning of a Calibration Device for Second Sound Based Quench Detection and Reconstruction Analysis

An important part of research and development (R&D) in the field of superconducting radiofrequency cavities is quench detection since these local breakdowns of superconductivity primarilylimit the cavity performance. Due to the detection of second sound waves propagating inliquid helium, the localization of quench spots on superconducting radio frequency cavities no longer requires the laborious attachment of many temperature sensors. Although second sound detection is widely used, estimating its accuracy is difficult and only few studies dealing with systematic uncertainties exist. Particularly helpful for this task is the artificial generation of second sound signals using a calibration device. Therefore, the already existing second sound system at the cavity test facility of Deutsches Elektronen-Synchrotron DESY is extended by calibration device prototypes in the framework of this thesis.It will be shown that ohmic resistors play a crucial role in the construction of such a tool. Heated by means of short electrical pulses, these resistors generate a second sound wave, which can be detected even within larger cryostats using noise cancelling algorithms and the existing reconstruction software. With the calibration device at hand, the influences of sensor positioning and quench location are thoroughly investigated