Luminosity measurement method for the LHC: The detector requirements studies

Absolute normalisation of the LHC measurements with a precision of O(1%) is desirable but beyond the reach of the present LHC detectors. This series of papers proposes and evaluates a measurement method capable to achieve such a precision target. In our earlier paper we have selected the phase-space region where the lepton pair production cross section in pp collisions at the LHC can be controlled with < 1 % precision and is large enough to reach a comparable statistical accuracy of the absolute luminosity measurement on the day-by-day basis. In the present one the performance requirements for a dedicated detector, indispensable to efficiently select events in the proposed phase-space region, are discussed.