The BTL (Barrel Timing Layer) project is an additional layer that will be added to CMS for the high luminosity phase of the LHC. BTL is half of the MTD project (Minimum Ionizing Particle Timing Detector) which will allow for higher-resolution event reconstruction.
Currently, the following prototypes have been manufactured at ldeaSquare:
Assembly centre service plate
Service plate optical fibre opening (subset of the service plate above)