Electron signals in the Forward Calorimeter prototype for ATLAS

Abstract

A pre-production prototype of the Forward Calorimeter (FCal) for the ATLAS detector presently under construction at the Large Hadron Collider (LHC) at CERN, Geneva, Switzerland, was exposed to electrons in the momentum range from 20 to 200 GeV/c in a test beam experiment at CERN in 1998. The measured performance, including a signal linearity within about ±1% and a high energy limit in the relative energy resolution of about 4%, meets the expectations for this kind of calorimeter, and exceeds the physics requirements for successful application in ATLAS.

Performance of the Atlas Forward Calorimeter and search for the invisible Higgs via vector boson fusion at ATLAS

“…The prediction for the FCal 2 was 6.1 ADC/GeV and 5.4 ADC/GeV for FCal 3. For FCal 2, this prediction is consistent to within ~ 5% of previous test beam results [23].…”

Calibration of the ATLAS forward calorimeter and a study of the top quark production cross-section measurement in the dilepton channel

“…For electrons and photons the energy resolution in the FCal is required to be better than [26]: Table 3.13. A zoom of the higher energy beam points is shown to the right in Figure 3.32(b).…”

“…When a particle interacts first with the liquid argon gap it produces a higher response, compared to when it hits the absorber first [26]. The fraction of the detector that is liquid argon is quite small (~ 1%), so there is a small fraction of particles that will first interact with the liquid argon gap, leading to few events in the high energy tail.…”

Readiness of the ATLAS liquid argon calorimeter for LHC collisions

“…Instead, seven sample pulse shapes recorded during the beam test campaign [9,10] have been averaged to obtain a normalized reference pulse shape for each layer. Figure 13 (bottom right) shows a typical example where the agreement between the reference pulse shape and the data is at the 4% level.…”

“…Until recently, the expected performance of the LAr calorimeter was extrapolated from intensive testing of a few modules with electron and pion beams from 1998 to 2003 [2][3][4][5][6][7][8][9][10], and in 2004 of a complete ATLAS detector slice [11][12][13]. The 20 months separating the completion of the installation from the first LHC collisions have been used to commission the LAr calorimeter.…”