The design of the Outer Tracker stations is
modular:
each detector module is constructed as
standalone unit. Later
four layers (XUVX) of detector modules are mounted in a
Station on Aluminum frames.
There is sufficient space for extending the span of stations beyond
the nominal acceptance to allow the use of modules of standard
width and height.
OT Station arrangement
OT Station front-view
Each detector module contains two staggered layers of straw tubes,
packed inside a gas-tight box.
Cross section of a straw tube module
In this respect,
the basic design of the straw tube modules has remained faithful
to the concept design in the
TDR, which is summarized in this
TDR excerpt.
This concept design has been finalized into a detailed engineering
design of various types of detector modules:
Types of OT Modules
modules of standard width (F, S1U, S1L, S2U, S2L)
contain 64 straw tubes per layer
modules with 32 straw tubes per layer (S3U, S3L)
occur above and below the
Inner Tracker acceptance area.
The complete assemblies of all these module types have been
implemented by the
Mechanical Engineering Department of NIKHEF
in the 3D computer-aided engineering design package
EDS (I-deas).
F Module 3D View
Exploited view of F Module assembly
The complete set of engineering drawings can be found
here.
Comforming to this module design, the main elements
of the straw tube modules are:
Two staggered layers of straw tubes
64 straw tubes (5mm diameter) per
layer
a wire locator every
800mm
a block at each straw end
Au-plated tungsten wires (0.025mm diameter)
Two sandwich panels to support the
straw tubes and provide the with an outer gas
envelope (secondary gas volume)
one thick core of light material
and two stiffening carbon-fibre "skins"
two aluminum inserts to provide
the module support in the Station Frames
Two side walls that join the panels
along the module length
Two feed-through PCBs to provide signal
and GND connections
Input and output gas pipes (for straw
and secondary gas volumes)
A detailed description of these elements can found
here.