Detector development towards axion searches with BabyIAXO

Abstract

The axion might be one milestone towards the solution of many long-lived problems in physics. The axion itself can couple by construction to photons via the Primakoff effect. Due to this, the Sun would be a large source of axions. To measure those axions, the inverse of the Primakoff effect can be used; within a strong magnetic field, providing virtual photons, the axions can convert into photons. Consequently, an experimental setup consisting of a large magnet pointing towards the Sun —called helioscope— can be used for the search for axions. Such an experiment is BabyIAXO, which is currently in development and proposed to be built at the DESY facility in Germany. <br/> The converted photons from the solar axions are in a typical energy range of 1-7 keV. To measure these specialised detectors need to be developed taking the low event rate into account. Thus, the detectors need to be very efficient, at the same time providing an extremely low background. These requirements can be fulfilled by gaseous detectors. <br/> In this thesis, the development and commissioning of such a detector will be explained. The central part of the detector will be a GridPix sensor, consisting of a pixelised readout with a gas amplification stage mounted atop. In order to reduce the background, suitable vetoes need to be developed as well as a mechanical design using only radiopure materials. Finally, the background rate will be determined and compared to previous GridPix detectors.