Cluster age–mass parameter space where at least 50% completeness can be achieved. Top panel: dependence on CBR, with results shown for the B3 field. Middle panel: completeness limits across three background fields, assuming the detection threshold of CBR≥0.4. Bottom panel: results for three different cluster geometric parameter combinations in the B3 field, also assuming CBR≥0.4. The results shown in the top and middle panels were determined using artificial clusters with R₅₀ = 0.25″−1.00″.