One year of FBG-based thermo-hygrometers in operation in the CMS experiment at CERN.
Berruti G.M., Petagna P., Buontempo S., Fienga F., Makovec A., Beni N., Szillasi Z., Consales M., Cusano A.
In this contribution we present results concerning the very first application of fibre optic sensors for relative-humidity monitoring in high-radiations environments. We have installed 72 thermo-hygrometers based on the Fibre Bragg Grating technology, in cold areas of the Tracker Bulkhead of the Compact Muon Solenoid experiment, where hundreds of electrical connectors are housed and thousands of services, including many cold pipes. In such a complicated environment, a constant hygrometric monitoring is vital, in order to avoid dangerous phenomena of condensation. We will report the results concerning temperature, relative humidity and dew point temperature measurements recorded during CMS operation throughout 2015.