# Figure 29

 TRD tracklet to TPC track residuals in $y$ as a function of the $z$~coordinate of the TPC track ($z_{\rm track}$)for supermodules 2~(left) and 6~(right). The colour code is linear in the numberof tracks. The upper and lower panels show the situation with the survey alignmentand with in addition the external alignment, respectively. The data are from a2012 run of \pp collisions with B~=~$-$\SI{0.5}{\tesla}. The alignment set used for the lowerplots was deduced from the same run. The internal alignment is applied in allfour cases.