Each target module contains a large-surface tracking section composed of honeycomb chambers.
These chambers are similar to the ones installed in 1996 in CHORUS
(Fig. 11)[51].
They are made up of closed hexagonal cells with a size of approximately 1 cm and
with a pitch of 1.2 cm.
Each cell has a thin (20 
) sense wire at about 2000 V potential
difference w.r.t. the wall of the cell.
This wall is made of preformed conductive plastic.
The operation of these chambers is similar to straw tubes.
The difference is that the construction of large planes is easier,
since wires can be positioned when the cells are still open.
Three orientations will be constructed rotated at 60 degrees with respect to each other.
Each orientation contains six wire planes.
This is sufficient to perform pattern recognition and to obtain three-dimensional information.
In the magnetic bending-plane additional wire planes are employed to increase the
momentum measurement capability.
An electronic design is available for these chambers, where each wire is
connected to its own multi-hit TDC.
The precision which can be reached in large systems is 200 per plane.
For a momentum determination employing measurements in one single module, combining silicon and honeycomb trackers, we estimate a total momentum resolution below 10% up to 25 GeV/c.
Figure 11:
Single and multi track events measured in the CHORUS honeycomb chambers.