Abstract
In 2018, a system of large-size triple-GEM demonstrator chambers was installed in the CMS experiment at CERN's Large Hadron Collider (LHC). The demonstrator's design mimicks that of the final detector, installed for Run-3. A successful Monte Carlo (MC) simulation of the collision-induced background hit rate in this system in proton-proton collisions at 13 TeV is presented. The MC predictions are compared to CMS measurements recorded at an instantaneous luminosity of 1.5 ×1034 cm-2 s-1. The simulation framework uses a combination of the FLUKA and GEANT4 packages. FLUKA simulates the radiation environment around the GE1/1 chambers. The particle flux by FLUKA covers energy spectra ranging from 10-11 to 104 MeV for neutrons, 10-3 to 104 MeV for γ's, 10-2 to 104 MeV for e±, and 10-1 to 104 MeV for charged hadrons. GEANT4 provides an estimate of the detector response (sensitivity) based on an accurate description of the detector geometry, the material composition, and the interaction of particles with the detector layers.The detector hit rate, as obtained from the simulation using FLUKA and GEANT4, is estimated as a function of the perpendicular distance from the beam line and agrees with data within the assigned uncertainties in the range 13.7-14.5%. This simulation framework can be used to obtain a reliable estimate of the background rates expected at the High Luminosity LHC.
Highlights
Environmental background hit rates on the CMS triple-GEM chamber in pp collisions at the LHC are evaluated by modeling radiation environment and detector response using a framework of FLUKA and Geant4 simulation packages
Geant4 simulation models particle interactions based on accurate material description of GEM chambers with an operation condition
The hit rates are obtained by combining sensitivity and particle flux, and compared with measurements at a luminosity of 1.5 × 1034 cm−2 s−1 at 13 TeV
Summary
The detector response is modeled using a Geant4 [13] simulation framework with the geometry of a triple-GEM detector [7] and incident background particles with properties consistent with those generated by the proton-proton collisions at the LHC. The dimensions and material composition for a single triple-GEM detector in figure 1 and table 1 approximates the prototype described in the GE1/1 detector technical report [7]. The coordinate system adapted by CMS is a right-handed cartesian coordinate system with the origin at the collision point, the x-axis pointing towards the center of the LHC ring, the y-axis pointing upwards and z-axis along the beam direction. The polar angel θ is measured from the positive z-axis to the x-y plane and the azimuthal angle φ is measured from the positive x-axis in the x-y plane
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
