STAR · PDF file13 Understanding the Distortion “Gap” goes (qualitatively, not...
Transcript of STAR · PDF file13 Understanding the Distortion “Gap” goes (qualitatively, not...
![Page 1: STAR · PDF file13 Understanding the Distortion “Gap” goes (qualitatively, not quantitatively) with anode gains. 14 TPC GridLeak distortion ... • SSD • Developing](https://reader030.fdocuments.in/reader030/viewer/2022020411/5a8524c47f8b9a9f1b8c4583/html5/thumbnails/1.jpg)
STAR Calibrations
Gene Van BurenBrookhaven National Lab
STAR Collaboration MeetingBNL - Feb. 23, 2005
![Page 2: STAR · PDF file13 Understanding the Distortion “Gap” goes (qualitatively, not quantitatively) with anode gains. 14 TPC GridLeak distortion ... • SSD • Developing](https://reader030.fdocuments.in/reader030/viewer/2022020411/5a8524c47f8b9a9f1b8c4583/html5/thumbnails/2.jpg)
2
Outline
• 2003 issues• SpaceCharge in dAu
• 2004 issues• GridLeak
• 2005 issues• Preparing for CuCu production
• Future?
![Page 3: STAR · PDF file13 Understanding the Distortion “Gap” goes (qualitatively, not quantitatively) with anode gains. 14 TPC GridLeak distortion ... • SSD • Developing](https://reader030.fdocuments.in/reader030/viewer/2022020411/5a8524c47f8b9a9f1b8c4583/html5/thumbnails/3.jpg)
3
dAu Issues (2003)
SpaceCharge effect observed in dAu via physical-signed DCAs. Is it a problem?
![Page 4: STAR · PDF file13 Understanding the Distortion “Gap” goes (qualitatively, not quantitatively) with anode gains. 14 TPC GridLeak distortion ... • SSD • Developing](https://reader030.fdocuments.in/reader030/viewer/2022020411/5a8524c47f8b9a9f1b8c4583/html5/thumbnails/4.jpg)
4
dAu Issues (2003)
• Strangeness showed no conclusive evidence that correcting this data helps low-PT issues for K0s.
• Contact me if you want to learn/study more. Mark Heinz
![Page 5: STAR · PDF file13 Understanding the Distortion “Gap” goes (qualitatively, not quantitatively) with anode gains. 14 TPC GridLeak distortion ... • SSD • Developing](https://reader030.fdocuments.in/reader030/viewer/2022020411/5a8524c47f8b9a9f1b8c4583/html5/thumbnails/5.jpg)
5
pp Issues (2004)
• Notable SpaceCharge!
• Correcting via scaler-based measures of luminosity.
![Page 6: STAR · PDF file13 Understanding the Distortion “Gap” goes (qualitatively, not quantitatively) with anode gains. 14 TPC GridLeak distortion ... • SSD • Developing](https://reader030.fdocuments.in/reader030/viewer/2022020411/5a8524c47f8b9a9f1b8c4583/html5/thumbnails/6.jpg)
6
SpaceCharge: E-by-E
• Fluctuations on the seconds time scale
• E-by-E handles this, but is problematic for ‘gaps’
Run 5044026: productionHigh
![Page 7: STAR · PDF file13 Understanding the Distortion “Gap” goes (qualitatively, not quantitatively) with anode gains. 14 TPC GridLeak distortion ... • SSD • Developing](https://reader030.fdocuments.in/reader030/viewer/2022020411/5a8524c47f8b9a9f1b8c4583/html5/thumbnails/7.jpg)
7
SpaceCharge: E-by-E
Run 5044026: productionHigh
Corrected to order 100 microns!
• Fluctuations on the seconds time scale
• E-by-E handles this, but is problematic for ‘gaps’
![Page 8: STAR · PDF file13 Understanding the Distortion “Gap” goes (qualitatively, not quantitatively) with anode gains. 14 TPC GridLeak distortion ... • SSD • Developing](https://reader030.fdocuments.in/reader030/viewer/2022020411/5a8524c47f8b9a9f1b8c4583/html5/thumbnails/8.jpg)
8
TPC GridLeak distortion
• Dependence on field, track charge, location, luminosity consistent with ion leakage at gated grid gap
![Page 9: STAR · PDF file13 Understanding the Distortion “Gap” goes (qualitatively, not quantitatively) with anode gains. 14 TPC GridLeak distortion ... • SSD • Developing](https://reader030.fdocuments.in/reader030/viewer/2022020411/5a8524c47f8b9a9f1b8c4583/html5/thumbnails/9.jpg)
9
TPC GridLeak distortion
• Dependence on field, track charge, location, luminosity consistent with ion leakage at gated grid gap
![Page 10: STAR · PDF file13 Understanding the Distortion “Gap” goes (qualitatively, not quantitatively) with anode gains. 14 TPC GridLeak distortion ... • SSD • Developing](https://reader030.fdocuments.in/reader030/viewer/2022020411/5a8524c47f8b9a9f1b8c4583/html5/thumbnails/10.jpg)
10
Understanding the Distortion
• “Gap” goes with luminosity - allows scaling with SpaceCharge (measure of lum.)
• Somewhat worse for half field
![Page 11: STAR · PDF file13 Understanding the Distortion “Gap” goes (qualitatively, not quantitatively) with anode gains. 14 TPC GridLeak distortion ... • SSD • Developing](https://reader030.fdocuments.in/reader030/viewer/2022020411/5a8524c47f8b9a9f1b8c4583/html5/thumbnails/11.jpg)
11
Understanding the Distortion
“Gap” varies ~linearly with z
![Page 12: STAR · PDF file13 Understanding the Distortion “Gap” goes (qualitatively, not quantitatively) with anode gains. 14 TPC GridLeak distortion ... • SSD • Developing](https://reader030.fdocuments.in/reader030/viewer/2022020411/5a8524c47f8b9a9f1b8c4583/html5/thumbnails/12.jpg)
12
Understanding the Distortion
• “Gap” varies ~linearly with z• No observed dependence on GG-opening
rate!
![Page 13: STAR · PDF file13 Understanding the Distortion “Gap” goes (qualitatively, not quantitatively) with anode gains. 14 TPC GridLeak distortion ... • SSD • Developing](https://reader030.fdocuments.in/reader030/viewer/2022020411/5a8524c47f8b9a9f1b8c4583/html5/thumbnails/13.jpg)
13
Understanding the Distortion
“Gap” goes (qualitatively, not quantitatively) with anode gains
![Page 14: STAR · PDF file13 Understanding the Distortion “Gap” goes (qualitatively, not quantitatively) with anode gains. 14 TPC GridLeak distortion ... • SSD • Developing](https://reader030.fdocuments.in/reader030/viewer/2022020411/5a8524c47f8b9a9f1b8c4583/html5/thumbnails/14.jpg)
14
TPC GridLeak distortion
• Correcting for the gap leaves some residual even smaller effects (still under study - a testament to the TPC that we can see them!)
![Page 15: STAR · PDF file13 Understanding the Distortion “Gap” goes (qualitatively, not quantitatively) with anode gains. 14 TPC GridLeak distortion ... • SSD • Developing](https://reader030.fdocuments.in/reader030/viewer/2022020411/5a8524c47f8b9a9f1b8c4583/html5/thumbnails/15.jpg)
15
GridLeak Distortion Correction
• Is the GL correction even worth doing?• In January, several PWGs started reporting issues
with the (at the time) current production.• Ran a test production using data under different
fields and luminosities.• PWGs indicated that most issues were improved.• There appear to be some remaining issues (K0s
mass in half field data).• Re-calibrated dE/dx and going again.
![Page 16: STAR · PDF file13 Understanding the Distortion “Gap” goes (qualitatively, not quantitatively) with anode gains. 14 TPC GridLeak distortion ... • SSD • Developing](https://reader030.fdocuments.in/reader030/viewer/2022020411/5a8524c47f8b9a9f1b8c4583/html5/thumbnails/16.jpg)
16
2005 Non-tracking detectors• BEMC focus is on 2003 & 2004 data calib.• EEMC gains done.• TOF doing their own thing this year.
![Page 17: STAR · PDF file13 Understanding the Distortion “Gap” goes (qualitatively, not quantitatively) with anode gains. 14 TPC GridLeak distortion ... • SSD • Developing](https://reader030.fdocuments.in/reader030/viewer/2022020411/5a8524c47f8b9a9f1b8c4583/html5/thumbnails/17.jpg)
17
2005 Tracking Detectors• SVT
• Calibration that don’t need tracking done.• Alignment needs to be redone (cone was removed
during the break) - awaits fully-calibrated TPC• SSD
• Developing methods for gaincalibrations and alignment(much to be done)
• FTPC• Calibs that don’t need TPC vertex
done (Gains, T0, d.v.)• Alignment/rotation needs fully-calibrated TPC
![Page 18: STAR · PDF file13 Understanding the Distortion “Gap” goes (qualitatively, not quantitatively) with anode gains. 14 TPC GridLeak distortion ... • SSD • Developing](https://reader030.fdocuments.in/reader030/viewer/2022020411/5a8524c47f8b9a9f1b8c4583/html5/thumbnails/18.jpg)
18
2005 TPC drift velocity• Initially done using
lasers, a process now automated, including insertion into DB (Javier & Jerome)
• Gets double-checked with vertex-matching from two TPC halves
• Still eventually want to use SVT (best)
DV from east lasersbefore outlier removal
Javier Castillo
![Page 19: STAR · PDF file13 Understanding the Distortion “Gap” goes (qualitatively, not quantitatively) with anode gains. 14 TPC GridLeak distortion ... • SSD • Developing](https://reader030.fdocuments.in/reader030/viewer/2022020411/5a8524c47f8b9a9f1b8c4583/html5/thumbnails/19.jpg)
19
2005 SpaceCharge + GridLeak
• SpaceCharge & GridLeak distortions comparable to what we had in AuAu
![Page 20: STAR · PDF file13 Understanding the Distortion “Gap” goes (qualitatively, not quantitatively) with anode gains. 14 TPC GridLeak distortion ... • SSD • Developing](https://reader030.fdocuments.in/reader030/viewer/2022020411/5a8524c47f8b9a9f1b8c4583/html5/thumbnails/20.jpg)
20
2005 TPC calibrations• Second TPC short for 1.5 weeks• Twist distortion calibration• SpaceCharge vs. Scalers
• Now have Scalers with higher sampling rates stored in the data stream.
• GridLeak vs. SpaceCharge• dE/dx calibration• Provide good tracking for SVT, good
vertex for FTPC
![Page 21: STAR · PDF file13 Understanding the Distortion “Gap” goes (qualitatively, not quantitatively) with anode gains. 14 TPC GridLeak distortion ... • SSD • Developing](https://reader030.fdocuments.in/reader030/viewer/2022020411/5a8524c47f8b9a9f1b8c4583/html5/thumbnails/21.jpg)
21
2005 TPC calibrations• Second TPC short for 1.5 weeks• Twist distortion calibration• SpaceCharge vs. Scalers
• Now have Scalers with higher sampling rates stored in the data stream.
• GridLeak vs. SpaceCharge• dE/dx calibration• Provide good tracking for SVT, good
vertex for FTPC
Wanted to understand
2004 AuAu first!
![Page 22: STAR · PDF file13 Understanding the Distortion “Gap” goes (qualitatively, not quantitatively) with anode gains. 14 TPC GridLeak distortion ... • SSD • Developing](https://reader030.fdocuments.in/reader030/viewer/2022020411/5a8524c47f8b9a9f1b8c4583/html5/thumbnails/22.jpg)
22
Future TPC• Higher-than-design luminosities brought
issues we did not expect (and have yet to fully understand)
Can we be surprised again at higher luminosities?• Lesson: fine details can become coarse!
• Are there issues in the current data of which we’re unaware? no measures?
Beating design spec despite!• Guarantee that a TPC replacement won’t
harbor surprises?
![Page 23: STAR · PDF file13 Understanding the Distortion “Gap” goes (qualitatively, not quantitatively) with anode gains. 14 TPC GridLeak distortion ... • SSD • Developing](https://reader030.fdocuments.in/reader030/viewer/2022020411/5a8524c47f8b9a9f1b8c4583/html5/thumbnails/23.jpg)
Summary• Same old
thing:always seems to be something new...
• Working to get calibrations to the point where they make great physics possible!
![Page 24: STAR · PDF file13 Understanding the Distortion “Gap” goes (qualitatively, not quantitatively) with anode gains. 14 TPC GridLeak distortion ... • SSD • Developing](https://reader030.fdocuments.in/reader030/viewer/2022020411/5a8524c47f8b9a9f1b8c4583/html5/thumbnails/24.jpg)
Extras
![Page 25: STAR · PDF file13 Understanding the Distortion “Gap” goes (qualitatively, not quantitatively) with anode gains. 14 TPC GridLeak distortion ... • SSD • Developing](https://reader030.fdocuments.in/reader030/viewer/2022020411/5a8524c47f8b9a9f1b8c4583/html5/thumbnails/25.jpg)
25
SpaceCharge : Zerobias
Run 5047041, Fill 4547
![Page 26: STAR · PDF file13 Understanding the Distortion “Gap” goes (qualitatively, not quantitatively) with anode gains. 14 TPC GridLeak distortion ... • SSD • Developing](https://reader030.fdocuments.in/reader030/viewer/2022020411/5a8524c47f8b9a9f1b8c4583/html5/thumbnails/26.jpg)
26
GridLeak Gap
• There is some remaining azimuthal dependence
![Page 27: STAR · PDF file13 Understanding the Distortion “Gap” goes (qualitatively, not quantitatively) with anode gains. 14 TPC GridLeak distortion ... • SSD • Developing](https://reader030.fdocuments.in/reader030/viewer/2022020411/5a8524c47f8b9a9f1b8c4583/html5/thumbnails/27.jpg)
27
psDCA vs. phi
• Something going on versus phi
Run 5046043 Run 5058060