Radiation environment of the LHCb Calorimeters during LHC Run 1 (2010-2013)

This paper presents the characterization of the prompt radiation levels experienced by the calorimeter system in the LHCb experiment during Run1 of LHC operation. A set of passive and active radiation detectors has been installed around and in between the LHCb calorimeter subsystems to measure different characteristics of the radiation environment. Cross calibrations between various types of measurements are performed and correlated with the evolving run conditions. Moreover, these measurements are compared to FLUKA simulation estimates and an evaluation of the reliability of the simulation in different running scenarios is provided. The simulation is based on a detailed geometry of the LHCb experiment and reflects the conditions of Run1 with 7 and 8 TeV CM proton-proton collision energies. A carefully characterized simulation of radiation levels in the LHCb experiment is essential in providing input for technical choices in view of the planned upgrade of the experiment for operation at higher luminosity.