\section{Radiation background}

{\it Discussion of expected cavern background and its uncertainty 
based on simulations and measurements with muon detectors, 
and finally give a reference figures and safety factor.
\begin{itemize}
\item Overview of cavern background. It's nature, origin, shielding strategy
\item Simulation result. R distribution in the small wheel region.
      14 TeV, Al beam pipe, 14 TeV steel beam pipe, 7 TeV steel beam pipe.
\item Measuremenents with pp collision. MDT, CSC
\item Summary figure. Reference figures.
\end{itemize}
}

\subsection{simulation}


