In order to avoid the problem of gaussian fits to momentum slices giving mean values that were unphysically less than zero, we can instead simply calculate the mean of the ADC values in the slice and fit to that.  Figure 1 below shows the results of this for the eta plane, and figure 2 for the phi plane.  As we have quite a lot of statistics now, I expanded the eta plane to four eta bins, from the previous two.  At Jan's suggestion, I dropped from 20 momentum bins to 4: the quality of the fit is not degraded that much by the change.  As before, the first row shows the results for 3-strip clusters, the second for 5-strip clusters, and the third for the high strip.

Figure 1:

Figure 2:

We can now look at the relation between deposited energy and particle momentum in simulation in the same way, using the same momentum range, the same number of momentum bins, and the same number of eta bins, and fitting lines to the mean in each momentum slice.  Unsurprisingly, the results from simulation are much more linear than what we got above.  In Figure 3, which shows the results for the eta plane the first column is for total eta strip energy and the second for max strip energy (since these plots are from single-particle simulations, there is no need to use a specific cluster size to determine the total energy deposited).  Figure 4 shows the results for the phi plane: the top is the total energy and the bottom is the max strip energy.

Figure 3:

Figure 4:

Attached is a pdf of all these plots.