Initial TRT L1 alignment in M8 was done with run 90275.
This run was chosen for: large statistics (76,000 events), B-field on, Xe gas, off-the-record approval from hw experts.
Aligned the TRT Barrel in 5 DoF, and the TRT endcaps in 6 DoF.
Track Selection:
In the alignment:
-pT > 2GeV, nSCT Hits > 5, nTRT Hits > 20
In the monitorign:
-pT > 5GeV, nSCT Hits > 5, nTRT Hits > 20
At this point the calibration for Xe had not been done in the barrel, the calibration that was used was the M.C based on data from the test beam.
The Starting alignment was HLT-UPD1-00.
This included a Si alignment, and the TRT alignment results from M6.
Ran 20 Iterations and convergence in the Barrel and Endcaps.
At this point:
-We saw large improvements in monitoring plots.
-There were large misalignment in the Endcaps O(mm).
-Were fairly confident with the barrel alignment.
So we made the decision to update the database with these results.
The TRT L1 Alignment was first done with respect to an early Si tag that was not in the db.
Full report given here.
The TRT L1 Alignment was repeated with the Si Alignment that became 'InDetAlign-HLT-UPD1-00'
The improvemts seen were essentially identical.
This set of constants became 'TRT_Cosmic_2008_02'.