The question is what c.m. energies correspond to different depths in the target; what beam energy we need to get a given c.m. energy at a given depth; and how many counts come from different depths (i.e. can we run with a thin target without sacrificing total count rate).
The cross section used is an approximation to the one found in the figure from Bardayan et al., reproduced in the expt proposal.
The figure below shows the total number of hits for a run at each of four different beam energies (only 17 s run time at the nominal beam current), from depths within each of five chunks within the 50 ug/cm2 target, plotted as a function of the average c.m. energy of those events within that chunk (with E(cm) standard deviation as x error bar).
N.B. The E(cm) given is the actual god-given number, not the number that would be reconstructed from measured energies. I can plot that too, but right now it's a sunny evening, so it will have to wait until tomorrow when it's forecast to rain. :D
Comments? questions? requests?
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