3D impression of the test storage ring TSR at the Max Planck Institut für Kernphysik (Heidelberg, Germany) as it was used for time dilation experiments. BPM - Beam profile monitor E-COOL - Electron cooler PM1 - Postion of photomultiplier 1 PM2 - Postion of photomultiplier 2 PM3 - Postion of photomultiplier 3