1. Stephen Trentalange STAR Upgrade Workshop June 11, 2012
FMS Status/Plan
Stephen Trentalange
STAR Upgrade Workshop
June 11, 2012

2. Improvements for Run 11 Repair of small cells
Change of HV profile to approx uniform acceptance in pT
Change from HT/Cluster triggers:
Board Sums (pions/etas)
Jet Patches

3. Acceptance of FMS

4. 2011: 500 GeV Trans/Long
Transverse Longitudinal

5. STAR Blue Beam AN As and alternative to Cross Ratio, the raw asymmetry
can be plotted as a function of Cos()
(with polarization axis at Phi=/2)
Slope =AN
Intercept = Luminosity Ratio for data set
Luminosity ratio for all ~ ±.05 %
Slope Fits are are consistent with Cross Ratio Method.
 of 0
STAR
 =0.07
AN=2.60±0.12 %
Luminosity
Ratio = ±0.08 %
AN=2.91±0.26 %
Luminosity
Ratio = ±0.18 %
AN=1.47±0.09 %
Luminosity
Ratio = ±.06 %

6. Transverse Single Spin 0 Asymmetry vs PT for small and large 0 isolation cones. (Errors shown are statistical)
STAR

7. Improvements for Run 12 Carl Gagliardi, Pibero Djawotho
Overlapping Jet Patches
Smoother acceptance for Board Sums for left/right rather than up/down
L0 Trigger simulation online

8. Six Overlapping Jet Patches: DSM Reprogramming
Add the encircled patches
Skip the X’ed patches
Six partially overlapping jet patches, each covering ~900 in azimuth
Four existing quadrants, plus two sides (where |cos φ| is large)
Give up top and bottom JPs (where |cos φ| is small)
Cluster (aka: Board) sum triggers
Only two thresholds for small cells (not a problem)
Can maintain three thresholds in the large cells
High tower triggers
Give up for small cells during physics running

9. Optimization of Board Sum Acceptance
In Run 11, small cell “cluster” (aka: “board”) sums were sums over sequential sets of four strips
Indicated by red lines (e.g., A0-3, A2+3+B0+1, B0-3, …)
Gave smooth acceptance across A-B-C (small |cos φ|)
Board D sat by itself (large |cos φ|)
Transverse spin measurements profit more from smooth acceptance at large |cos φ|, rather than small |cos φ|

10. Present Scheme Rotated inputs to boards B and C in each quadrant
New B
Boards A and D unchanged
New C
Rotated inputs to boards B and C in each quadrant
Job for FMS group, not Trigger group
Small cell “cluster” (aka: “board”) sums over sequential sets of four strips
Put Board A by itself (small |cos φ|)
Gives smooth acceptance across B-C-D (large |cos φ|)
Simple change in small cell DSM Layer-0 algorithm

11. 2012: 200 and 510 GeV Running 200 GeV 500 GeV
+ read out during Cu+Au running….

12. FMS Status: Data Participation
Run 11
Transverse 500 GeV p-p ~20 /pb
Longitudinal 500 GeV p-p ~2/pb
Run 12
200 GeV p-p Transverse ~20 /pb
500 GeV p-p Longitudinal ~90 /pb
Cu+Au ~2 weeks

13. Problems with FMS LED triggering problems
Evidence for Graying of Lead Glass
Lecroy HV
Bad cards
Observed strange excursions of voltage
Possible origin of ‘gain jumps’ in large cells
CW HV: Lost 1 week of running
Bad device (1/2 of cells)
2 Bad cards
~ large cells /36 small cells problems
No FPD in Run 12
Problem with communication between FEQ and STP
Need FPD*FMS

14. Need for LED Monitoring of PMT Gains
ETA Yield
NO LED corrections
WITH LED corrections
ETA

15. Evidence for Graying of Glass
LARGE CELLS
SMALL CELLS
Blue = April
Black= Mar
Ratio of LgBs/SmBs increases by factor of 2 over 30 days
~15% increase in slope corresponds to -0.5% /day gain change for pp 500 Run 12

16. Evidence for Graying of Glass
PION MASS
LED
DAY
DAY
Consistent with YuXi Pan’s estimate 0.2%/day for Run11 ~ 0.5 inst. Lum of Run 12

17. Evidence for Graying of Glass
Run 11: 0.2%/day
Run 12: 0.5%/day ~2x intensity
Total graying ~ 25% for Run11/12
Conclusion: Leave it alone for Run 13
Unstack after Run 13
Repair large PMT bases
Expose glass to sunlight to anneal f-centers

18. FMS Cell Status

19. FMS Repair Plans July-November Repairs: FPD communications
UCLA:Stephen Trentalange, YuXi Pan
PSU: Steve Heppelmann, Chris Dilks
TAMU: Carl Gagliardi, Mriganka Mondal
Repairs:
LED setup, set number of RHIC clock tics
Test of Lecroy HV stability
Repair of CW mother board/ dead channels
FPD communications

20. View of charged track in magnetic field
For a charged particle exiting
the constant field of a solenoid
magnetic field through the a
hole in a flux returning cap,
about ½ of the angular
bend in the constant field
region is negated in the return
region.
sagitta

21. Forward Magnetic Tracking Summary
A measurement of the charged track trajectory just inside the flux return (about 3 meters from the magnet center) can be projected to
either the interaction vertex
or to the FMS.
The displacement between the projected track and measured track will be called .

22. View of charged track in magnetic field
For a charged particle exiting
the constant field of a solenoid
magnetic field through the a
hole in a flux returning cap,
about ½ of the angular
bend in the constant field
region is negated in the return
region.
Region of PoleTip Carriage
sagitta

23. Magnetic Field Mapping for FMS Extrapolation Method
Extrapolate to FMS requires fringe field measurements to ~0.1(res)x0.5(fringe bend)B0sin(theta) =5%*B0sin(theta) ~25 Gauss
Problem: Pole Tip Carriage ~ Gauss disturbance

24. Conclusions FMS needs repair work over the summer
Still capable of physics addressing pions, etas, jets, J/Psi?
Extend to correlations with FPD, mid-rapidity in Run 13
Needed upgrades for different physics goals are the subject of this workshop
Magnet mapping might be necessary for tracking in the forward region

28. LED Channel Map

29. Problems with FMS Loss of LED signal/power supply
Loss of LED after power dips
Combination of losses ~ several days
Mostly effects large cell data (~10% of cells)
Graying of Lead Glass
Large cell HV problems
Run11: ~12 channels for several days
Run 12: ¼ of large cells lost HV for several days (controller)
Small cell HV problems
Helped to use onboard register to store HV value
Loss of control to half of detector (Device 1)
Loss of FPD
Flakey communication between FEQ and STP
Need FPD*FMS coincidence trigger