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    User name R. Michaels

    Log entry time 16:10:38 on November21,2005

    Entry number 160903

    keyword=rate predictions

    For E = 1.1 GeV we will be significantly higher than the proposal.
    Here are some rates. These are for point-targets with no detailed
    averaging over accepantance, so they are correct to about +/- 20%.

    1. Pb208 for proposal (E=0.85 GeV)
    Rate = 14.3 MHz / uA / arm (i.e. per microAmp and per HRS)
    This is different from proposal for the above reason (point calc...)

    2. Pb208 for E = 1.1 GeV
    cross section drops a factor of 6.3
    Rate = 2.3 MHz / uA / arm

    3. The C12 foils on the target.
    They are 150 microns, there are two of them (front/back) and
    they suffer rad loss as does Pb. The loss is a factor of 0.34.
    So the thickness is 150 microns x 2 x 0.34
    Rate = 0.42 MHz / uA / arm = 18 % background (it is a much smaller
    background for the proposal).

    For reference here are two fixed targets we may try:

    4. C12 optics foil 0.0838 g/cm^2 = 0.038 cm
    Rate = 4.9 MHz / uA / arm (this is assuming no radiative loss)

    5. Alum dummy, 1 mm thick (2 such foils)
    Rate = 9.3 MHz / uA / arm