Two algorithm variations. The S/N landscape is shown here uncapped for illustration, but it is capped in the binning algorithm as described in Sect. 4.3.2. In both panels, the solid curve represents a S/N of 30σ. Left: Modified S/N landscape and the resulting binning solution for the galaxy cluster CL0016+16. Here, the output kT bins are required to fulfil four simultaneous criteria: (1) to have a target S/N of 30σ (denoted by the solid curve); (2) to have a minimum S/N ≥3σ; (3) to include at least two S_X bins; and (4) to increase in width with a logarithmic factor of 1.2. Right: Optimal binning for the low S/N cluster RXJ0030.5+2618, obtained from fixing the number of output kT bins to four and maximising their resulting S/N (see Sect. 4.3.3).