Dear experts,
After the telescope alignment, I run AnalysisTelescope with the updated geometry to produce the telescope resolution plot at DUT, as attached. However, it is not centred around zero. Is there something wrong?
Thanks.
Hi Yang,
you’re right - once you’ve reached the best possible alignment, your residuals should be cenrered at zero.
But:
As you describe it, you run the telescope alignment and then look at the DUT residuals. Those are two different things.
After performing the telescope alignment, the (biased or unbiased) residuals of the telescope planes vs. the reconstructed track should be centered at zero (you can find the biased residuals in the Tracking4D module).
In order to get the alignment for the DUT right, you need to employ another module called AlignmentDUT. Else, only those planes that are used for the track reconstruction (i.e. the telescope planes) are shifted and rotated during the alignment.
For a step-by-step guide please have a look at our manual and read Chapter 7.
I hope that helps. Let us know how you proceed.
Best,
Jens
In fact, the above plot was produced in the AnalysisTelescope module with the updated geometry after AlignmentTrackChi2 and then AlignmentDUTResidual as well. I checked the
AnalysisTelescope module in the manual:
The Monte Carlo particle position is compared with the track interception with the DUT.
Below is the DUT residuals plot in the AnalysisDUT module, which looks fine.
Hi,have you solved it?
@zhiliang the issue was likely just looking at a global coordinates residual while having some rotation on the DUT.