HERA-B uses a set of 8 ribbons with 
m thickness parallel to the beam
and 
m length along the beam axis, which are positioned around the
beam at a distance of 4 - 6 
. The targets are grouped in two
stations with a distance of 4 cm along the beam axis s.
Within one station the 4 different targets
are located at nearly equal s-positions and approaches the beam from all
4 different sides.
Since the rebuilt of the HERA west right straight section the HERA-B target
is located at WR09. The mechanics is mounted on a 2 m long vacuum
vessel which mainly houses the HERA-B vertex detector system (VDS) [10].
Figure 9: Targets mounted in the VDS vessel.
Fig. 9 shows two photos of already mounted
targets in the open VDS vessel. The targets are mounted
on a ceramic fork and they are electrical connected to the outside
of the vacuum vessel; providing a measurement of the interaction rate on
a target by means of a induced charge measurement in the wire.
The second photo shows a part of the RF shielding and the target cage in the
VDS vessel. Protons are passing from right to left.
The stepping motors which moves the wires have a nominal step-size of 50 nm.
The precision and the clearance fit are in the 
m range.