Here are the new numbers, using E0=56.5 GeV. For the tagged end of the spectrum (k/E0 ~ 0.85 -0.95); the fraction of photons thru the target should be about 88% (as compared to ~80% at 4 GeV).

As before, the half-angles are
primary collimator: theta_coll = 0.5 * 8.61mm/5800mm   = 0.742 mr
RadPhi target            theta_targ = 0.5 * 25.4mm/40800mm = 0.311 mr

At E0 = 5.650 GeV (RadPhi run)
    theta_crit = 0.511/5650 = 0.0904 mr
    theta_coll/theta_crit = 8.20
    theta_targ/theta_crit = 3.44

             At E0 = 5.65 Gev
k/E0      Fraction through
           coll.      target
0.95      .979        .893
0.90      .977        .882
0.80      .973        .868
0.50      .964      .846
0.20      .959      .835

At E0 = 4.045 GeV (old web page plots),
    theta_crit = 0.511/4045 = 0.1263 mr
    theta_coll/theta_crit = 5.87
    theta_targ/theta_crit = 2.46

             At E0 = 4.045 Gev
k/E0      Fraction through
           coll.      target

0.95      .960        .812
0.90      .955        .797
0.80      .948        .781
0.50      .935    .753
0.20      .928    .740