Figure 28

Left: Cosmic-ray tracks with at least 100~TPC clusters and 5~TRD layers,recorded without magnetic field, used for the relative $r\varphi$ alignment ofthe TRD chambers within stacks (internal alignment) Right: Charged-particle tracks with at least 100~TPC clusters and 4~TRDlayers from \pp collisions at $\sqrts=8$~TeV, used for the alignment of the TRDwith respect to the TPC (external alignment). Both figures show data from 2012 (setupwith 13~supermodules).
[png]   [pdf]   [eps]
[png]   [pdf]   [eps]