Module position

[YifanC]

For MR5, the module position is set in the detector yaml file for Module0123 sequentially as:

tpc_offsets: # cm # [x (drift), y (vertical), z (beam)]
  - [33.5, 0., 33.5]
  - [33.5, 0., -33.5]
  - [-33.5, 0., 33.5]
  - [-33.5, 0., -33.5]

The center of 2x2 is set to be (0,0,0) in the new geometry (.gdml) used in MR5. As a reference, the module position in MR4 is

tpc_offsets: # cm # [x (drift), y (vertical), z (beam)]
  - [33.5, -268, 1333.5]
  - [33.5, -268, 1266.5]
  - [-33.5, -268, 1333.5]
  - [-33.5, -268, 1266.5]

The module layout in MINOS hall is shown in the picture below which is also linked in this slides

I thought we are extremely lucky that the layout coincides with what we have been using so far. However, this is only valid if we are using a right-hand coordinator system which means when you look along the beam, y is vertically pointing up, x is from right to left, which is also unusual when you look at the detector projections... I am not sure how the coordinate system is set in GENIE and edepsim. Need to double check to ensure we are not randomly flipping the coordinates.