Accuracy of different detector configurations. As one adds perpendicular-oriented detector plates, and since the background radiation is isotropic and does not scale with the cosine of the incidence angle, the S/N depends on the relative inclination angles of the detector plates. It is best for a single plate (green), and gets worse for two plates inclined by 90 degrees (blue), and even worse for three plates inclined by 90 degrees (red; corresponding to the five-detector case for any given GRB).