\subsubsection*{Purpose, Resolution Requirements, Description, Mass, Channel Count}

The FDCs include 4 separate packages of disk-shaped horizontal drift chambers 
to measure the momenta of all charged particles emerging from the target at 
angles of up to 30$^{\circ}$ relative to the photon beam line.  Each package
consists of 6 planes of anode wires (119 wires with 1.0~cm spacing) with 
150~$\mu$m spatial resolution sandwiched between 2 planes of cathode strips 
(119 strips with 5~mm pitch).  By charge interpolation of the electron 
avalanche image charge in the cathode strip readout, spatial resolutions at 
the cathode planes are expected of roughly 100~$\mu$m.  The strips are 
arranged in a $U$ and $V$ geometry with respect to the wires (at 
$\pm$45$^{\circ}$), allowing the reconstruction of a 3--D space point from 
each hit.  Adjacent chamber elements will be rotated by 60$^{\circ}$ with 
respect to each other to improve the overall resolution.  The wires that 
cross through the beam line will be deadened out to a radius of 3.5~cm to 
reduce the rates.  Each FDC package has a channel count of 2150, leading to 
a total channel count for the full FDC system of 8600 (2900 A, 5700 C).

\subsubsection*{Raw Signals, Stages of Amplification, Final Readout}

Each signal from the FDCs (anodes and cathodes) will be amplified by 
single-channel transimpedance preamplifiers mounted directly on the FDC 
circuit boards.  The signals from the anode wires that are above some 
pre-determined voltage threshold will be discriminated and then digitized 
by 40~MHz F1 TDCs.  The signals from the cathodes will be digitized with 
250~MHz 8-bit flash ADCs.

\subsubsection*{R\&D Issues, Simulations, Monitoring and Other Considerations}

The primary development issues that must be addressed for the FDC system
are factors affecting the intrinsic resolution of the chambers, along with 
the mechanical and electronics layout.  The goal is to construct a tracking 
detector that meets the required design specifications and has a long life 
time, a uniform and predictable response, a high efficiency, and is 
serviceable in case of component failure.

Two detector prototypes will be completed and studied over the course
of the next two years.  The first will be employed to study the optimal 
electrode configuration for the system.  A second full-scale prototype
will be completed to test mechanical support designs for the chamber 
cathode planes and wire planes, which is necessary to avoid electrostatic 
instabilities and non-uniformities that are known to affect resolution. 
This second prototype will also be essential to complete the final design 
of the FDC circuit boards.  A significant aspect of the design work includes 
development and study of Monte Carlo of the GlueX detector system focussing 
on the properties of the FDC system that will enable us to meet or exceed 
the required design specifications.

The detector group at Jefferson Laboratory is developing the gas system
for the entire GlueX experiment.  The Ohio University group will work
to ensure that this design is adequate for the control and monitoring
of the FDC system.

\subsubsection*{Manpower, R\&D and Production Schedules}

The FDC prototyping and design is primarily the responsibility of
the Ohio University group, with important support from the detector
group at Jefferson Laboratory.  The manpower available is adequate
to complete the detector R\&D within 2 years and to complete the
detector construction with 4 years pending availability of funds.

