Tracking studies show that with reasonable assumptions about Run II
conditions, the Forward Proton Detector will have quite good acceptance
for detecting scattered protons and anti-protons. The dipole spectrometer
has excellent acceptance for anti-protons, especially at low |t| and
high 
.
The addition of quadrupole spectrometers
allows the tagging of protons, and thus double pomeron and elastic events,
as well as generally improving the intermediate and high |t|
acceptance. Our design with spectrometers in
both the horizontal and vertical planes makes this acceptance very robust,
and insulates us against accelerator uncertainties.
Although the 
quadrupole pots have inferior total
acceptance to the dipole pots, they improve the |t| coverage,
are crucial for elastics and
halo rejection, and will allow the
calibration of the dipole spectrometer.
The quadrupole total
acceptance is quite stable for both protons and anti-protons
with at the 1-2% level,
with a 
GeV
and 
ranging from about 2.5
GeV at low to 3.9 GeV at high . The dipole acceptance for
's
increases sharply with from about 2% at low to near 100% at high
. The minimum dipole |t| varies from about 0.3 to 0 GeV
for 
(with acceptance to 
for 
), while
the maximum |t| ranges from 4.1 to 1.8 GeV.
A summary of the spectrometer acceptances are given in Table 4.
Table 4: Properties of dipole and quadrupole spectrometers.