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.

Wire Splitting FT Upper FT Lower
Exploited view of 1m Module half exhibiting the details
of Feed-Through and Wire-Splitting boards



The Technical Specification, including schematic drawings and the list of geometrical dimensions, can be found in the technical note "Definition of Feed-Through and Splitting Boards".



Feed-Through PCB


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.

FT Upper
more FIGURES
Drawing (PS file)

Assembled PCB with
GND spring & SMD conn.

Bare PCB: pads

Bare PCB: GND plane
FT Lower
more FIGURES
Drawing (PS file)

Assembled PCB with
GND spring & SMD conn.

Bare PCB: pads

Bare PCB: GND plane


Wire-Splitting PCB

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.

Wire-Splitting PCB
more FIGURES
Drawing (PS file)
FT Center
more FIGURES
Drawing (PS file)