% Responsible A.~Andronic, R.~Bailhache, C.~Lippmann, K.~Oyama

\chapter{Front-end Electronics Integration onto ROCs}

This chapter intend to explain how to prepare the ALICE TRD readout chambers
for integration and how to equipp them with all electronics components. It is
still under preparation and we need feedback from all people who work for chamber
integration. Any question, comments, and contributions are welcome.

\section{Getting ROC}

\begin{figure}[h]
  \centering
  \includegraphics[width=11cm,angle=0]{photos/BareChamber.jpg}
  \caption{A bare TRD readout chamber. It must be equipped with the readout
    board mounting screws (72 for C0, 96 for C1 chambers) before you start.}
  \label{bareTRD}
\end{figure}

We start with a bare TRD readout chamber, as shown in Fig. \ref{bareTRD}. It
must have been equipped with the readout board mounting screws (72 for C0, 96
for C1 chambers). Moreover it should have holes with M3 threads in the aluminum
of the backpanel and in the aluminum L-profile as shown in Fig. ??. These
will ensure a stable contact of the readout board (ROB) digital and analog
grounds to the chamber body, as will be shown later.

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\section{Putting Spacer for ROBs}

\begin{figure}[h]
  \centering
\includegraphics[width=12cm,angle=0]{photos/ROBSpacerMaterial.jpg}
  \caption{Some ready-cut readout board spacers.}
  \label{robsp}
\end{figure}

The spacer material (polyethylene foam) is x00\,$\mu$m thick .... 
It is cut in stripes which are about 45\,cm long (about the length of a 
readout board) and 5\,cm wide. A pile of spacers is shown in Fig. \ref{robsp}.

The spacers are put on the chamber as shown in Fig. \ref{robsp1}. Two
short pieces (about 1x2\,cm$^2$ each should be enough) of double sided
tape (Lomann xxx???) keep the spacer material fixed to the chamber
body. The long edge of the spacer should be on top of the edges of
the holes of the backpanel, where the signal cables are fed through
(See Fig. \ref{robsp2}), because here the signal cables will pull
down the ROB. This stress should be relieved at these positions by
the spacer material. The short edges should be positioned at the approximate
positions of the ROB edges. If there are screws, the corner of the spacer must
be cut for proper positioning. This step takes about 30-60\,mins for one 
person.

\begin{figure}[p]
  \centering
\includegraphics[width=11cm,angle=0]{photos/FinishedWithROBSpacers.jpg}
  \caption{A chamber completely equipped with ROB spacers.}
  \label{robsp1}
\end{figure}

\begin{figure}[p]
  \centering
\includegraphics[width=11cm,angle=0]{photos/PuttingROBSpacers.jpg}
  \caption{Closeup on ROB spacer on chamber. It should be close to signal
    cable holes.}
  \label{robsp2}
\end{figure}


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\section{Bending Signal Cables}

Bending the signal cables is easiest done before the ROBs are put on the
chamber. Do this work only if somebody who knows how to do it has shown it to
you and if you were qualified to be able to do it.

This step takes about 20-40\,mins for one person.

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\section{Selecting ROBs}

Only ROBs that are marked as ``good'' in the data base (gateDB)
are allowed to go on a chamber. The data base can be accessed
via

\url{http://alice.physi.uni-heidelberg.de/gate/}.


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\section{Charge Pump Capacitors}

We have to check that the charge pump capacitors are soldered on the
board. Fig. ??

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\section{Putting ROBs on ROC}

While handling the ROBs extreme care has to be taken in order not to bend
them too much. ROBs should be transported only firmly attached with screws
on the transport boards. However, when putting them on the chamber, they 
can not be attached to these boards anymore. Thus a special lifting device, 
the ``pizza lifting fork'' has to be used, which assures that the ROBs stay 
flat while they are laid onto the chamber. 
This fork is shown in Fig. \ref{fork}.

We have seven different types of readout boards. On a C1 chamber we put all
seven types, on a C0 chamber we put only five types, as shown in Fig.
\ref{positions}:

\begin{itemize}
\item C0: 2xT1A, T3A, T1B, T2B, T3B.
\item C1: 2xT1A, T3A, T4A, T1B, T2B, T3B, T4B.
\end{itemize}

After putting the ROBs on the chamber, do also make the corresponding 
updates in the gateDB.

Fig. \ref{robs} shows a C1 chamber with two out of eight ROBs placed on the
spacer material. The whole procedure of putting ROBs on a chamber takes about
15-30\,mins for one person.

\begin{figure}[p]
  \centering
\includegraphics[width=11cm,angle=0]{photos/positions.jpg}
  \caption{The eight ROB positions and the corresponding ROB types to
    go on these positions. The chamber is seen from top (The radiator surface
    is lying flat on a table). The positions where the additional DCS and ORI
    boards are mounted are also indicated. A C0 chamber has only six ROBs.
    Here the T4A and T4B board at positions 6 and 7 are not present.}
  \label{positions}
\end{figure}

\begin{figure}[h]
  \centering
\includegraphics[width=11cm,angle=0]{photos/StartPuttingROBs.jpg}
  \caption{}
  \label{robs}
\end{figure}


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\subsection{Preparing ROB T2B with DCS Boards}

\begin{figure}[h]
  \centering
\includegraphics[width=11cm,angle=0]{photos/DCSwithShieldspacer.jpg}
  \caption{}
  \label{dcs}
\end{figure}

hello.

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\subsection{Preparing ROB T3A and T3B with ORI Cards}

\begin{figure}[h]
  \centering
\includegraphics[width=11cm,angle=0]{photos/PuttingORI.jpg}
  \caption{}
  \label{ori}
\end{figure}

hello.



%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\section{Cable boards}

\begin{figure}[h]
  \centering
\includegraphics[width=11cm,angle=0]{photos/PuttingCableBoards.jpg}
  \caption{Two cable boards of type {\it CLK, PRE and DATA in Z} connecting
  a T1A and a T3A ROB. They are red in a newer version.}
  \label{cboards}
\end{figure}

We can now put the cable boards which connect the slow control serial network,
the clock and trigger lines and the data lines from board to board. There are
five types, which can be distinguished by their different colors and connector
types, but also by their labels. Each type is available in different lengths
for the different chamber sizes. The five types are the following:

\begin{description}
\item[PASA-PHI:] These transfer some analog PASA signals from one ROB to
  another. There are 4 different lengths. The cable boards are green and
  have 16-pin connectors. They are used only to connect boards along
  $\phi$-direction of a chamber.
\item[CLK, PRE and DATA in Z:] These transfer clock, pretrigger and data signals
  along the $z$-direction of the chamber. There are 4 different lengths. They
  are red and have two 40-pin connectors.
\item[SCSN and SD in Z:] These transfer slow control and shutdown signals in
  $z$-direction. There are 4 different lengths. They are red and have two
  16-pin connectors.
\item[SCSN/SD-PHI16:] These transfer slow control and shutdown signals in
  $\phi$ direction between T3A and T3B boards and between T4A and T4B boards,
  respectively. There are 4 different lengths. They are blue and have two
  16-pin connectors.
\item[SCSN/SD-PHI20:] These transfer slow control and shutdown signals in
  $\phi$ direction between T1A and T1B boards and between T1A and T2B boards,
  respectively. There are 4 different lengths. They are blue and have two
  20-pin connectors.
\end{description}

This step in the integration procedure takes about 5-10\,mins.

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\section{Fixing ROBs to the chamber}

Each ROB is fixed to the chamber by 12 screws, which are glued onto the
backpanel of the chamber. We use 12 plastic washers and 12 plastic nuts
to permanently fix the ROBs. That makes 96 screws for a C1 chamber and is
providing a lot of fun. The screws should be tightened not too hard!

This step takes about 60-120\,mins for 1 person.

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\section{ROB Grounding Connection}

There are two types of grounding connections: between the ROBs grounds, and
between the digital and analog grounds of each ROB and  the chamber body. Pieces of Cu with
one sided tape are used. They have two different sizes for the two types of
connections. After they have been glued, they are finally soldered on the
ROBs. Moreover to ensure a stable contact with the chamber body the Cu band is
fixed with two screws, a bigger one for the aluminum of the backpanel and a
smaller one for the aluminum  L-profile.     

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\section{Connecting Signal Cables}

\begin{figure}[h]
  \centering
\includegraphics[width=10cm,angle=270]{photos/TightningConnectors.jpg}
  \caption{The tightening of the connectors between the signal cables
  and the MCMs.}
  \label{conn}
\end{figure}

The bended signal cables are inserted into the HARWIN connectors on the ROBs.
Care has to be taken while doing this in order to assure a good connection.
The connectors are closed with the special tool as shown in Fig. \ref{conn}.

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\section{Cathode Wire Plane Connection}

The cathode wire plane has to be connected to the PASA ground in the middle
at the edge of the chamber between the T4A and T4B boards, or the T3A and T3B
boards for a C0 chamber. The red wire is fixed with scotch along the edge of
the chamber as shown in Fig. \ref{fcgnd}.

\begin{figure}[h]
  \centering
%\includegraphics[width=11cm,angle=0]{photos/FCWireConnection.jpg}
\includegraphics[width=11cm,angle=0]{photos/cathode-wires-conn.jpg}
  \caption{The cathode wire plane connection to the ground of ROBs.}
  \label{fcgnd}
\end{figure}


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\section{H.V. Filter Box}

The eight anode and one drift HV cables have to be connected to the HV filter
box as shown in Fig. \ref{hvbox}. The filter box should be temporarily fixed 
on the chamber's side in between the two copper tape ground connections 
closest to the chamber's end where the drift cable is (see Fig. \ref{hvbox}).
Then each HV cable has to be cut at the proper length and prepared for
soldering on the filter box. This preparation comprises the following steps:
\begin{enumerate}
\item removing the outer (red) isolation for a length of about 12 mm
\item disentangling and binding the copper mesh, adding solder and cutting 
it to the proper length (2-3 mm)
\item removing the intermediate (black) isolation over the whole length
of the 12 mm
\item removing the inner (transparent) isolation for about 3 mm and adding
solder
\end{enumerate}
Then follows soldering the ground (copper mesh) and active (inner wire) 
of each cable on its proper place on the filter box.
The field cage ground cable (thin simple wire) has to be connected to the
ground of the filter box. The last step involves connecting with a similar
thin wire the ground of the filter box to the closest (to the right) ground
connection on the ROBs.

Special care has to be take when cutting the cables, Their bending and their
path on the chamber's side has to be checked in order that they do no exceed
the chamber's body (L-profile) by more than 5 mm. This step is eased by 
attaching them temporarily with tape to the chamber body.

\begin{figure}[h]
  \centering
%\includegraphics[width=11cm,angle=0]{photos/PreparingHVFilterBox.jpg}
 \includegraphics[width=11cm,angle=0]{photos/HV3.jpg}
 \caption{The filter box with soldered HV cables on the side of the chamber.}
  \label{hvbox}
\end{figure}


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\section{Summary}

\begin{figure}[h]
  \centering
\includegraphics[width=11cm,angle=0]{photos/FullEquippedL0C1.jpg}
  \caption{}
  \label{finished}
\end{figure}

% EOF
