muons produced from the dumping of the beam passed through the entire detector, depositing large signals in every cell of the HCAL, with equivalent energy ranging between hundreds of  to a few . A schematic representation of the geometry of the “beam splash” setup is shown in Fig. \[fig:JordansSplashDiag\].

The signal from “beam splash” muons has a well-defined time with respect to the arrival of the LHC bunch and to the LHC clock. The time-of-flight of the muons from the collimators to the geometrical centers of each cell was calculated and used to predict the expected timing versus $\eta$ for all HCAL cells. The data were averaged over all $\phi$ values at each $\eta$ value to obtain an HCAL $\eta$ timing profile. The resulting distribution of the differences between the measured and predicted times is shown in Fig. \[fig:uncorrectedVsCorrectedSplash\](a). The timing measurements for the barrel region are distributed around zero within $\pm1$ ns, demonstrating the correctness of the delay settings calculated from beam tests. The timing for the endcap before any phase corrections exhibits an average time difference that is 10 ns later than the barrel. The x-shaped pattern and the structure at $|\eta|>1.4$ in the outer calorimeter are understood 