The picture shows a cavity resonator, on which the detectors planned by GravNet are based.

Links
- https://www.pi.uni-bonn.de/en/news/university-of-bonn-participating-in-two-erc-synergy-grants/hochraumresonator.jpg/image_view_fullscreen
- https://www.pi.uni-bonn.de/en/news/university-of-bonn-participating-in-two-erc-synergy-grants/hochraumresonator.jpg/@@download/image/Hochraumresonator.jpg