Parameters chosen for the default TB+PMT setup:

Origin= front face of PMT.
y-axis is the beam axis.
W thickness = 3.095mm on average
PMT thickness = 1.5 mm (Hamamatsu data sheet, if I read it correctly)
Si thickness = 300 um (295 um bulk +15 um sensitive)
Si density = 2.33 g/cm^3
W density = 19.3 g/cm^3
PMT in slot 19, i.e. 23 mm away from tungstene front face,
Tungstene thickness = 3*3.095 = 9.285 mm = 2 slots (#15+#14+#13)
Distance between Si layers = 5.7 mm
1 layer = 5.7mm air + 0.3mm Si First layer in slot #11, so 6mm away from tungstene back plane
Second layer in slot #8, third in #5 and fourth in #2.
Origin of beam = -3.5 m from PMT front face.

-- AnnemarieMagnan - 14 Mar 2008