Illustration of the components of the fit background, equation (2), based on reference [20]. The total time-dependent background rate, , is the black solid line. It is composed of the time-independent rate, , (red dot-dashed line), the time-dependent γ-ray background rate in the neutron detectors, , (green dashed line), and the time-dependent background due to scattered neutrons, , (purple dotted line). The count rate axis is on a log scale.