OT Geometry

Module Position

The basic OT geometrical structure and naming conventions are discussed in the introduction (following the LHCb note LHCb-2003-041).

Here it is described the positioning of the straw-tube modules on the C-Frames.

By construction, the straw tube modules are built out of two "mono-layers" of straws, conventionally called "A" and "B". These two types of panels are identical, except in the details of the straw length, as schematically shown in the figure below (details in the Engineering Drawings).


In the detector construction and installation, straw mono-layers become detector elements through the following steps: Due to this combination of construction and installation features, the straw-tube modules present a few "asymmetries".

The first one is due to the staggering of the two mono-layer by half straw pitch in X (e.g. the schematic top view in the figure below).


The second one is specific to the F Modules, and it is due to the the various straw lengths, that results in a "staggering" in Y of the "dead" region (e.g. see the schematic side view in the figure below).


The details of the position and geometry of each straw-tube module are given in the Module Location Page (and in the Module Location Database).