LHCb OT Module Components Feed-Through & Wire-Splitting Boards
The Feed-Through PCB and
the Wire-Splitting PCB
are an integral part of the detector modules.
Their essential function is to carry the pads to which
the anode wires are soldered.
Exploited view of 1m Module half exhibiting the details
of Feed-Through and Wire-Splitting boards
Feed-Through Board showing the PCB, the signal
connector and the ground spring
The Feed-Through boards provide
the electrical connection between the signal wires (anodes) inside the
gas box and the Front-End Electronics outside. On the inner side of the board,
the wires are soldered onto pads on the PCB,
while on the outer side an SMD connector
is placed to provide the interface to the Front-End Electronics.
The Feed-Through board also provides the connection to a
common ground reference
via a continuous ground layer following the path of the signal.
The cathode of the straws and the (inner) Aluminum side of the panels
are directly soldered onto the GND layer of the board.
A special contact spring provides then the ground connection to the
Front-End Electronics.
As integral parts of the straw-tubes modules,
the mechanical details of
the Feed-Through boards are described in the
sub-assembly drawings. From the mechanical point of view, there are
two types of Feed-Through boards, namely "U" and "L",
depending on which module end they fit into.
The longest straw-tubes modules (type "F") are split
into two independent readout sections: the cathode straws as well as the
anode wires are interrupted around the center of the module.
The Wire-Splitting board is a completely passive PCB (wires are left floating),
the only function of which is to provide solder pads for the anode wires split
in the module center.
As the board represents a dead area in the middle
of the acceptance, its width is minimized.
