\documentclass{article}
\begin{document}

\title{Precision Drift-Tube Chambers for the ATLAS Muon Spectrometer at Super-LHC}

\author{O.~Kortner$^1$, H.~Kroha$^1$, F.~Legger$^1$, R.~Richter$^1$, A.~Engl$^2$, F.~Rauscher$^2$}
\maketitle 

\begin{center}
$^1$ Max-Planck-Institut f\"ur Physik, Munich

$^2$ Ludwig-Maximilian University, Munich
\end{center}

The muon detectors of the ATLAS experiment at the Large Hadron Collider (LHC) at CERN
are designed to operate under unprecedentedly high background rates. At
the LHC design luminosity of $10^{34}$ cm$^2$s$^{-1}$, the Monitored
Drift Tube (MDT) chambers of the ATLAS muon spectrometer have to cope
with neutron and gamma ray background rates of up to 500~Hz/cm$^2$
in the inner chamber layers of the forward regions of the detector. 
At the Super-LHC, the high-luminosity upgrade of the LHC,
background rates are expected to increase by an order of magnitude. 
The resulting high occupancies lead to a significant
deterioration of the muon detection efficiency compromising the
physics goals.  The possibility to improve the muon detection efficiency at the
Super-LHC by reducing the diameter of the pressurized aluminum drift tubes from 
presently 30~mm to 15~mm has been investigated. We report on the tests of a
prototype drift-tube detector with thin-walled aluminum tubes of 15~mm diameter
at the Gamma Irradiation Facility at CERN with counting rates as expected 
at Super-LHC.
\end{document}
