CMS is a particle physics experiment at the Large Hadron Collider (LHC) at CERN, and is one of two general-purpose detectors at the LHC.
Upgrades are required to cope with the anticipated increase in the beam luminosity of the LHC from 1034 to 1035 cm−2s−1. The main motivation for a luminosity upgrade is to extend the physics reach of the LHC and to study with greater precision the discoveries expected to be made at the LHC since, after several years at maximum luminosity, the statistical gains gradually decline with time, or integrated luminosity.
Higher luminosity will result in higher particle fluxes, detector occupancies, trigger rates, and radiation damage. The inner tracking detectors are expected to have reached their design lifetime and will need complete replacement, with new systems adapted to the even harsher environment.
As a result of the large luminosity increase, the tracking system is to be replaced and new technological solutions found for the innermost region because of high particle fluxes and radiation levels. The remainder of the CMS detector will remain intact and continues to operate well. The major upgrade of the CMS trigger system will be mainly of processing electronics located in the underground counting area outside the radiation zone.
The upgrade will enable the UK to maintain its leadership in this area, which would be required in order to capitalise fully on the original LHC investment and to guarantee continued access to world-leading energy-frontier science from 2015 onwards.
Imperial College London
STFC Rutherford Appleton Laboratory
University of Bristol