A time profile of the event on 7 September 2005. These are three kinds of time profiles from the solar neutron event on 7 September 2005, e.g., the MC calculation of the SciCRT, the data, and the MC calculation of the Mexico SNT. The Geotail hard X-ray peak time is 17:36:40 UT shown by a dot dash line. The vertical axis shows the count rates per 2 min on the left and the significance on the right. These vertical axis are normalized by the standard deviation calculated from background. The black line shows the data corresponds to the neutral channel (>30 MeV) on Mexico SNT. The red line is the best fit to the data assuming impulsive eruption of solar neutrons. These significance for the count rates per 5 min become 17, 32, and 53 σ, respectively (Nagai et al. 2014).