Acceptance Function for PREX using the Hall A spectrometers with 5 degree Septum Magnet Dec 5, 2011 Robert Michaels Contents of this directory foldedacc.dat -- (ASCII text file) -- the acceptance function \epsilon(\theta) first column is scattering angle (degrees) second column is the relative probability to reach the detector compareAccPb.gif -- plot of acceptance function and comparison to simulation. prex_acceptL.gif -- a picture of the acceptance. Horizontal and vertical angles in radians. The smallest scattering angle is on the right. Comments on the acceptance function. Results are averaged over two spectrometers and have been corrected for multiple scattering. Theoretical comparisons should use this function to integrate over the acceptance of our spectrometers. As an example, the average asymmetry is (latex format): $$ A = \frac{ \int sin(\theta) d\theta A \frac{d\sigma}{d\Omega} \epsilon(\theta)} {\int sin(\theta) d\theta \frac{d\sigma}{d\Omega} \epsilon(\theta)} $$ where $\frac{d\sigma}{d\Omega}$ is the cross section. contact Robert Michaels Jefferson Lab e-mail : rom@jlab.org