I found some numbers related to the BAT geometry from Craig's report. BAT_Z of top-of-CZT = 0.35 [cm] BAT_Z of top-of-mask-tile = 100.3 [cm] (The top-of-CZT to top-of-mask-tile distance is 99.95 cm.) MASKOFFX = -0.109 +/- 0.003 [cm] MASKOFFY = 0.078 +/- 0.002 [cm] MASKOFFZ = 0.105 +/- 0.008 [cm] These numbers should be included in the simulation coordinate system.