Calculation of slope

[laborleben]

1. should the slope vector be a normalized vector? See

   testbeam_analysis/testbeam_analysis/track_analysis.py

   Line 657 in 44eacad

   return datamean, slope, chi2

2. What about

   testbeam_analysis/testbeam_analysis/track_analysis.py

   Line 655 in 44eacad

   intersections = offset + slope / slope[2] * (hits.T[2][:, np.newaxis] - offset[2]) # Fitted line and DUT plane intersections (here: points)

   , where the slope vector is divided by its third component?

[laborleben]

addressing 2. Ok, this is clear to me when you assume that the plane is parallel to x-y-plane.
But for the real chi2 we need the rotated plane, which is usually not parallel to the x-y-plane.

[DavidLP]

Well spotted, I opened a bug report #35.

[DavidLP]

1. We can normalize the direction vector of the track (slope), but we do not have to.

[laborleben]

OK, I see, I'll check if the normalization has some influence on further data processing.

[DavidLP]

Questions answered.