\section{Introduction {\small [TK]}} 


We propose to build a pair of new small wheel detector (NSW) to replace the
existing ones during the second long shutdown\footnote{
Currently it is foreseen in 2018.}
of the LHC during which the 
LHC will be upgraded to achieve its luminosity beyond the nominal design value
and up to 2-3$\times 10^{34}$ cm$^{-2}$s$^{-1}$ 
in the following running period.
The goal of NSW is to bring a significant enhancement of the muon performance 
in the endcap region, in particular of the level-1 muon trigger as well as the
precision muon tracking, that would not be achieved by simple and thus
lower cost modifications alone such as improvement of radiation shielding,
addition of new detector layers or upgrade of electronics.

The muon small wheel is a part of the ATLAS muon spectrometer located in 
the endcap region in front of the endcap toroidal magnet.
This is the innermost station of the three muon stations of the endcap.
There are two identical sets of detectors in both sides of ATLAS.
The small wheel consists of 4+4 layers of monitored drift tubes (MDT) 
for precision tracking in the bending direction ($R$ direction) 
and two layers of thin gap chambers (TGC) for azimuthal coordinates.
These detectors cover the $\eta$ range of $1.3 < |\eta| < 2.0$.
The inner part of the small wheel is covered by four layers of 
cathode readout chambers (CSC) because of its high rate capability.  
Each CSC layers determines both bending and azimuthal coordinates.
The coverage of the CSC chambers is $2.0 < |\eta| < 2.7$.




Just to check if reference works~\cite{Aad:2009wy}.
Once more to see the order is OK~\cite{Aad:2008zzm}.

