Speaker
Description
Gaseous photodetectors, especially those working in the UV range, have become well established. Due to the sensitivity of the photocathode materials, reaching the visible light range is still a great challenge. Using THGEMs for electron amplification, one can in theory scale the detectors indefinitely. This could open new opportunities for applications such as indirect neutrino detection in large-area experiments.
We have launched an R&D project towards the development of a scalable photodetector that can detect high-frequency visible light. The detector is based on THGEMs coated with a photosensitive material. Finding a suitable photocathode material concerning quantum efficiency and longevity is a crucial point in this endeavor. Especially in the visible light range, longevity is a challenge. During this project, different photocathode materials, suitable for various wavelength ranges, will be investigated. Especially regarding durability, Diamond-like carbon could be a promising material. A dedicated setup was built to perform benchmark measurements with CsI photocathodes in vacuum and Ar-CH4 (90-10). The 20x40 mm2 photocathode is deposited on gold THGEMs via electron beam evaporation at the Technical University of Munich. Afterwards, first quantum efficiency measurements in the VUV region were performed with a DLC GEM obtained from the CERN PCB laboratory and will be discussed in this contribution. In addition, we explore the possibility of coating THGEMs with DLC layers at TUM with the pulsed laser deposition technique. This allows us to produce a thin DLC film that can be deposited onto the THGEM or to directly coat the THGEM. The feasibility of both options will be presented
