MEG/MRI-compatible optical fiber holder for photodiode

To precisely determine stimulus timing in neuroscientific experiments, a photodiode attached to the screen is often used. As running ferromagnetic cables into MRI-/MEG-chambers should be avoided, I installed an optical fiber running from the stimulus presentation screen out of the chamber, where the transmitted brightness was measured via a small circuit and an Avago SFH250 photodiode connected to the MEG acquisition computer.

To hold the optical fiber to the screen in our CTF275 MEG without