A vital requirement of the experiment is the reduction of accidental background to a level of $10^{-11}$. The purpose of the CHANTI (\textit{Charged Anti-counter}) is to tag particles propagating at angles larger than that allowed for the beam as they emerge from the last station of the Gigatracker. Such particles can be produced by inelastic interaction of the beam with the collimator and upstream material.\\

A set of large angle guard counters is therefore installed immediately after the Gigatracker (see \figurename~\ref{img:det:chanti}). Further stations, sensitive in the closest region to the beam, can veto the beam halo muons.\\

The CHANTI is made of six double-layer stations \cite{na62-tdr}. Each station is a 30$\times$30~\si{\square\centi\meter} square with a 90$\times$50 \si{\square\milli\meter} rectangular hole to allow the passage of the beam. Each layer is composed of 24 (22) scintillator bars aligned to the $x$ axis ($y$ axis). Light is collected by wavelength-shifting fibers, and transported to one side of the station, where a silicon photomultiplier is placed.\\

\begin{figure}
\centering
\includegraphics[width=\textwidth]{Images/pdf/na62/detector/chanti_full}
\caption{Sketch of the six CHANTI stations on the beam line \cite{na62-tdr}.}\label{img:det:chanti}
\end{figure}