During the first half of 1999 the Radphi experiment underwent a major
upgrade in which the recoil proton detector was replaced by a scintillator
hodoscope covering angles from
to
in the lab, and a
barrel calorimeter was added. By increasing the detector coverage both for
the recoil proton and for gammas in the barrel, the experiment improves
both its acceptance and its ability to discriminate background from signal
events. The increase in acceptance comes at a cost of increased trigger
rates and data acquisition overhead, which can offset the gains by requiring
the experiment to run at lower intensity or higher dead time. This is a
major concern to Radphi, whose primary physics goals require obtaining the
highest statistics possible. This note summarizes what we expect for the
increase in trigger rates in the upgraded detector, based upon Monte Carlo
simulation.