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\documentclass{chowto}

\title{ENGE Honeycomb Drift Chamber}
\howtotype{reference} % ``expert'', ``user'', ``reference''
\experiment{HKS}
\author{Akihiko Matsumura and Toshinobu Miyoshi}
\category{enge}
%\maintainer{Name of person maintaining document} % Optional
\date{May 18, 2005} % Can use \today as the argument

\begin{document}

\begin{abstract}
This documents basic information of ENGE honeycomb cell 
Drift Chamber.
\end{abstract}

\section{Purpose}
ENGE honeycomb Drift Chamber (EDC) measures trajectory of scattered electron
and determines position and angle at detection plane.
This is mounted ENGE magnet exit.

\section{Specification}
EDC which cell size is 5 cm has 10 planes (xx', uu', xx', vv',xx') 
and x' (u', v') plane is shifted by half of cell from x (u, v) plane 
(figure \ref{fig:EDCgeom}). u and u' (v and v') planes are tilted by
30 degree (-30 degree).

 \begin{figure}[ht]
 \begin{center}
   \epsfig{file=honeycomb-OHDCModel.eps,width=5.0cm}
 \caption[Wire geometry of EDC]{Wire geometry of EDC}
 \label{fig:EDCgeom}
 \end{center}
 \end{figure}


\section{Operational parameters}
EDC has 5 SHV input connectors for each pair planes. 
Without beam, the current should be almost zero. The operational
HV and threshold are decided from the result of performance test at
Laboratory of Nuclear Science (LNS), Japan.
As a result pf this test, we got total position resolution of
210 $\mu$m. The efficiency is almost 100\% if -HV is above 2100 V
and will decrease if threshold is above 4.0 V.

 \begin{table}[ht]
 \begin{center}
 \begin{tabular}{cc}
 \hline\hline
   HV & -2200 V \\
   Threshold & 2.0 V \\
   Gas content & Ar/C$_{2}$H$_{6}$ 50:50 \\
   \hline
 \end{tabular}
 \caption{Operational parameter for EDC}
 \label{tab:EDCope}
 \end{center}
 \end{table}

The signals from anode wires go into Nanometric N277L cards for 
preamplifying and discriminating. There are 70 cards for EDC, 
35 on top side and 35 on bottom side. N277L card need both +5 and 
-5 power input. The voltage are supplied by two Acopiann power 
supplies respectively. The output signals from cards go into
F1 TDCs via 33 ft. flat cables.

\section{Tracking Parameter}
These are the main parameters for EDC.\\

\verb|edc_tdc_min_win, edc_tdc_max_win|: In edc.param . Select a good hit
in this window.\\

\verb|edc_layer_time_zero|: In edc.param . Set time zero of ALL cards 
(total 70 variables).\\

\verb|edift_coeff|: In edriftcoeff.param . Constants for 3-order polynomial
to calculate drift distance from drift time. 0-order, 1-order, 2-order and
3-order of ALL cards (total 70 variables) are required. 

\end{document}

% Revision history:
% $Log: honeycomb.tex,v $
% Revision 1.1.2.1  2005/05/20 04:00:42  saw
% Initial version
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