Spatial correlation length r₀ for γ = 1.8 and ϵ =  −1.2 considering the homogeneous 10 ks based observations as a function of the flux limit of the sample in the soft band (filled and empty circles correspond to the Ebrero and Hasinger Φ_x(L), respectively) and in the hard band (filled square, open squares and open hexagons correspond to the Ebrero, Ueda and La Franca Φ_x(L), respectively).