Power spectrum of simulated half-mission null test. The plots in the left column are computed using SRoll1 while those in the right column are computed with SRoll2. The two lower frequencies are shown in the two cases when the ADCNL is included in the input and when it is not. These plots demonstrate the efficiency of the SRoll2 method to remove the ADCNL residuals while the previous method left some artefacts at very large scale.