Are any photomultipliers used in any of LHC detectors? Or are only semiconductor devices used?
If yes, then where?
Yes, photomultipliers are in use in calorimeters which use Cerenkov light to detect the passage of particles. An example is in this preprint of the Castor detector at CMS in LHC.
If you go to the document search page of CERN and search for photomultipliers and CMS you will find many references, though most behind paywalls. This is how I got the preprint above.