CSC Alignment using the GlobalChi2 Alignment Algorithm

Here, one can find all the information about the CSC alignment steps we have followed to achive our goal. In this case, we have used the Double Cone geometry, that means 2328 barrel modules (Pixels+SCT), therefore 13968 DoFs. We have used release 13.0.20 with the following tags for:

- Multimouns: InDetRecExample
- Cosmics in the Pit: InDetCosmicRecExample

Official Alignment Constants

These constants are the 'final' alignment sets. The second one was used for the Detector Paper. The detector description used was ATLAS-CSC-01-00-00 and database tag OFLCOND-CSC-00-00-00.

CSC Exercise
Detectors	Si Alignment	Geometry	Tracker	Samples	Alignment Constants	DB tag
Si+TRT	L1+L2+L3	Full system	GlobalChi2Fitter	Multimuons + NoBF Cosmics	(pool.root) (db) ()	OFLCOND-CSC-00-01-04
Si+TRT	L1+L2+L3	Full system	GlobalChi2Fitter	Multimuons + BF Cosmics	(pool.root) (db) ()	OFLCOND-CSC-00-01-05

• More information for the OFLCOND-CSC-01-00-04 tag:
  A "beam constraint" alignment from the SiGlobalChi2Algs in combination with cosmic tracks (16k SCT + 88k TRT Volume) (16/10/07, PB)
• More information for the OFLCOND-CSC-01-00-05 tag:
  A "beam constraint" alignment from the SiGlobalChi2Algs in combination with cosmic tracks and B-field ON (O(10)k with TRT barrel filter) (05/11/07, PB)

Set IV (02-October-2007)

References

Here, one has the summary plots for the Perfect case to allow comparation tasks (these plots have been taken with the same tags as the alignment constants):

CSC Multimuons and Cosmics in the Pit using the Double Cone geometry (release 13.0.20)
# Iter	Description	Sample	Detectors	Tracker	ErrorScaling	Events	Tracks	Hits	Local Pos	Global Pos	Summary Plots
0	Perfect Geometry	Multimuons	Silicon	GX2 Fitter	No	50k	191361	2136163	()	()

Data used

Geometry notes:

• Multimuons uses ATLAS-CSC-01-00-00 as tag geometry

/castor/cern.ch/grid/atlas/caf/misal1_mc12/misal1_mc12.007270.MultiMuonsGeneration.digit.RDO.v12003102_tid003678

• Cosmics (Silicon) uses ATLAS-CommNF-02-00-00 as tag geometry

/castor/cern.ch/user/l/lytken/cosmic_13010/

• Cosmics (SCT only) uses ATLAS-CommNF-00-00-00 as tag geometry (where the pixel positions and SCT EndCaps are not the same as for CSC. It doesn't affect as we only use SCT Barrel modules in this sample)

/castor/cern.ch/user/l/lytken/cosmic_1250/dig-files/

Known Problems

• Global phi0 shift (~1.7 mrad)
• Global z shift (~ 300 µm)
• GlobalChi2 can be smaller, mean: 3.045 (for the Perfect case, the mean is 1.617). Maybe we could perform another iteration but...
• Just Double Cone geometry aligned. So, our aim is to have the alignment constants for the Full System.

Detailed results

CSC Multimuons + Cosmics in the Pit using the Double Cone geometry (release 13.0.20)
# Iter	Description	Sample	Detectors	Tracker	ErrorScaling	Events	Tracks	Hits	Local Pos	Global Pos	Summary Plots
0	Out of the box reco	Multimuons	Silicon	GX2 Fitter	Yes	50k	126713	1161227	()	()
- Level 0 Alignment: Align Constants from the multimuon sample: (pool.root) () - Summary Plots:
1	L0 corrected	Multimuons	Silicon	GX2 Fitter	Yes	50k	126697	1161185	()	()
1	L0 corrected	Cosmics	Silicon	CTB	No	-	-	-	()	()
1	L0 corrected	Cosmics	SCT	CTB	No	-	-	-	()	()
- Level 2 Alignment: Align Constants from the multimuon sample and the two cosmic samples: (pool.root) () - Summary Plots: -
2	L0+L2 corrected	Multimuons	Silicon	GX2 Fitter	Yes	45k	164872	1746627	(-)	(-)
2	L0+L2 corrected	Cosmics	Silicon	CTB	No	-	-	-	(-)	(-)	-
2	L0+L2 corrected	Cosmics	SCT	CTB	No	-	-	-	(-)	(-)	-
- Level 2 Alignment: Align Constants from the multimuon sample and the two cosmic samples: (-) (-) - Summary Plots: -
3	L0 corrected	Multimuons	Silicon	GX2 Fitter	Yes	45k	166410	1779818	(-)	(-)
3	L0+L2 corrected	Cosmics	Silicon	CTB	No	-	-	-	(-)	(-)	-
3	L0+L2 corrected	Cosmics	SCT	CTB	No	-	-	-	(-)	(-)	-
- Level 2 Alignment: Align Constants from the multimuon sample and the two cosmic samples: (-) (-) - Summary Plots: -
4	L0 corrected	Multimuons	Silicon	GX2 Fitter	No	30k	93549	994676	(-)	(-)
4	L0+L2 corrected	Cosmics	Silicon	CTB	No	-	-	-	(-)	(-)	-
4	L0+L2 corrected	Cosmics	SCT	CTB	No	-	-	-	(-)	(-)	-
- Level 2 Alignment: Align Constants from the multimuon sample and the two cosmic samples: (-) (-) - Summary Plots: -
5	L0+L2 corrected	Multimuons	Silicon	GX2 Fitter	No	30k	94518	1005994	(-)	(-)
5	L0+L2 corrected	Cosmics	Silicon	-	No	-	-	-	(-)	(-)	-
5	L0+L2 corrected	Cosmics	SCT	-	No	-	-	-	(-)	(-)	-
- Level 3 Alignment: Align Constants from the multimuon sample and the two cosmic samples: (-) (-) - Summary Plots: -
6	L0+L2+L3 corrected	Multimuons	Silicon	GX2 Fitter	No	15k	56954	636120	()	()
- Level 0 Alignment: Align Constants from the multimuon sample: (pool.root) (db) () - Summary Plots:
7	Final test	Multimuons	Silicon	GX2 Fitter	No	15k	56951	636090	()	()

NOTE 1: Level 0 was done using the track parameter correlations à la CDF. Our L0+L2 should correct the CSC L1+L2.
NOTE 2: The "Tracks" and "Hits" columns are the ones within the selected geometry.

Alignment Constants

CSC Multimuons + Cosmics in the Pit
Description	Si Alignment	Geometry Config	Modules (DoFs)	VtxFit	Tracker	# Iters	Alignment Constants
Starting from the nominal (set IV)	L1+L2+L3	DoubleCone	2328 (13968)	Yes	GlobalChi2Fitter	6	(pool.root) (db) ()

-- CarlosEscobar - 16 Sep 2007