Histograms of data photon counts for all response bins with the energies 1.00–1.78 GeV (top), 10.0–17.8 GeV (middle), and 178–316 GeV (bottom). Photon counts and histogram pixel counts are shown on logarithmic scales. The number of pixels with zero observed photons, n₀, is displayed as text in each panel. The apparent photon count sparsity in the < 10 counts regime is caused by the sparsity of integer numbers on the logarithmic scale in that regime. Figure 4 shows the residual histograms of the selected bins.