These are the coordinates at ground level of simulated cosmic rays.

-- MathieuBlom - 27 Jun 2007

• This is a plot of the surface coordinates of the simulate cosmic rays from MuVol_noField_allevts.fix.aan.root. The accumulations in the figure are due to the two shafts. Cosmics that travel through the shaft are more likely to reach the the detector. The two shafts are drown in the figures, but their real coordinates are uncertain. The red cirkel is at 20m from the origin and has a radius of 18m, the blue cirkel is at -25 m with a radius of 12m.
  

this also shows the coordinates at surface, but for the truth parameters at the surface:

The file ground_coord_orig_cut.gif shows only cosmics with 1/trk_mc_qoverp < 20 GeV. It seems that only particles that travel through the shaft are able to make it to the detector. Although the coordinates of the shafts or not precisely known this plot makes it very likely that we see them.