%The Target Chamber                                 Steve Chappell

\chapter{The Target Chamber}

The full mechanical design specification for the MEGHA target chamber
can be found in the document {\itshape ``Multi Element Gas Hybrid
Array'', S.J.  Metcalfe, Mechanical design office, Daresbury Laboratory
(1994) and related updates.} Brief notes concerning usage of the
chamber are given below.

\section{Beamline}

The MEGHA chamber is mounted on ``Line A'' of the Linac Hall
(experimental area 2) at the ANU.  It may utilize beams accelerated by
the 14UD tandem Van de Graaff at this facility with or without post
acceleration in the Linac booster.

\section{Targets \& Target Ladder}

The target drive, guide tube and loading mechanism are located in the front
portion of the target chamber. At present it consists of a manual drive which
raises/lowers a ``target rod'' and the target frame attached to it. Up to
five standard ANU targets may be loaded onto the frame. Targets are
replaced by lowering the target ladder into the ``target loading tube''
located below the beamline entrance to the chamber. This allows targets
to be replaced when the chamber is under vacuum.

\section{Collimation System}

Collimators and antiscatter apertures are mounted on ceramic inserts inside
the ``collimator tube''. These inserts may be placed at any position
within the tube. This tube is mounted inside a guide which is fixed to the
chamber entrance. The collimator tube slides freely within the guide
such that apertures may be placed at the desired position with
respect to the target. The collimator tube is loaded through the
``collimator box'' at the chamber entrance. This ``box'' has a removable
lid and contains feedthroughs for connecting the apertures to a current
meter. A ``standard set'' of Daresbury type apertures is available.

\section{Detection Systems}

Two detection systems have been developed for use in the MEGHA chamber.
These consist of:\\
{\bfseries 1)} A ``Gas--Hybrid'' array of up to 44 close packed
Scintillator--Solid State Position Sensitive Detector--Ionisation
chamber telescopes. These are mounted in nine-telescope modules, five
modules comprising the full array. The modules plug into ports at the rear
of the chamber.\\
{\bfseries 2)} A Silicon Strip detector array catering for up to
10 detectors. These mount on a removable support placed inside the
front portion of the chamber.\\
These systems are described in the following chapters of this
manual.
