Abstract
The Minimum Bias Trigger Scintillators (MBTS) delivered the primary triggers for selecting events from real LHC collisions with the smallest bias for the low luminosity LHC RunI fills from 2009-2013 (proton-proton, lead-lead and lead-proton collisions). Similarly, for the next RunII of LHC (2015-2018) MBTS will provide key ingredients for the first physics measurements at larger LHC collisions energy (charge multiplicity, proton-proton cross section, rapidity gap measurements, ... ) and in general for low luminosity LHC fills.
After more than 25 fb-1 of proton-proton collisions delivered during RunI, MBTS detectors have been substantially upgraded in preparation of RunII. The upgrade strategy is presented including the scintillator replacement, the modified read out scheme, the optical measurements on RunI scintillators assessing the degradation due to the dose received.