Speaker
Margret Fincke
(Univ. of Victoria)
Description
Although LHC data-taking is expected to continue for a number or
years, plans are already being developed for operation of the LHC and
associated detectors at a increased instantaneous luminosity about 5
times the original design value of 10$^{34}$ cm$^{-2}$ s$^{-1}$. The
increased particle flux at this high luminosity (HL) will have an
impact on many sub-systems of the ATLAS detector. In particular, in
the LAr forward calorimeter (FCal), which was designed for operation
at LHC luminosities, the associated increase in the ionization load at
HL-LHC luminosities poses a number of problems that can degrade its
performance, related to beam heating, space charge effects in the LAr
gaps and HV losses due to increased current draws over the HV
current-limiting resistors. One solution to these problems, which
would require the opening of both endcap cryostats, is the
construction and installation of a new FCal, with cooling loops,
narrower LAr gaps, and lower value protection resistors. A second
proposed solution, which does not involve opening the cryostats, is
the installation of a small warm calorimeter in front of the FCal,
resulting in a reduction of the particle flux to levels at which the
existing device can operate normally.
The talk will review the design of the ATLAS forward calorimeter and
discuss the effects that are expected to degrade the performance at
HL-LHC luminosities as well as the proposed upgrade scenarios.
for the collaboration
ATLAS Liquid Argon Calorimeter Group
