Data and different background estimations for the time around GRB 110920A in the reconstructed energy range from 102 to 295 keV for detector na with a time-bin size of 5 s. The four solid lines are derived with the classical approach of fitting polynomials to the time before after the transient event, each with a different definition of these times (1: −100 s to −90 s and 150 s to 200 s; 2: −100 s to −70 s and 50 s to 200 s; 3: −100 s to 0 s and 100 s to 200 s; 4: −100 s to −50 s and 400 s to 500 s). Additionally the best fit of our background model is plotted as a dashed green line.