FMS Update: Spin PWG. Stephen Trentalange April

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1 FMS Update: Spin PWG Stephen Trentalange April

2 Summary of FMS Operations FMS is performing well and is fairly stable. No sign this year of runaway trigger Solved problem with Lecroy Voltage instabilities Monitoring programs by Chris Dilks Repair and Replacement of unstable cards/controllers: Chris Dilks Minor HV problems with small cells (loss of 8 cells) Replacement daughter boards being repaired/fabricated by PSU Receive replacements this week. Need spares. Replacement of DSMs(1) and QT boards(4) during run Bit checking and monitoring of problems by Akio Ogawa Damage to lead glass Trigger rate monitor by Chris Dilks Evaluation of damage by Steve Heppelmann/S.T. FPS is installed and running: Data being examined by Akio Ogawa Correlations with Roman Pot Triggers being examined: Chris Dilks We have achieved our goals for p+p transverse and (most likely) p+p longitudinal (limited by syst error in rel. luminosity) Propose new voltage iteration before end of longitudinal running to compensate for gain loss: prepare for p+au run

3 BUR Runs 15-17

4 FMS 200 GeV Transverse/Longitudinal Run Have achieved transverse goals in luminosity and FOM, probably even after QA cuts; Longitudinal is ~50% of central rapidity goal. Comparable to previous years.

5 FMS Run QA: Christopher Dilks

6 Acceptance/Relative Luminosity

7 π/γ/jet Asymmetries: (~10% of data) 15tran/asym_plots/asym_web.html A TT A N A Σ Pion Energy [GeV] A N A N A Ν Pions/Gammas/Jets Transverse Momentum [GeV/c] asymmetry-update

8 Indications from Preliminary Analysis No major problems with analysis chain Possible indication of interesting behavior at low pt-> may wish to lower threshold/prescale for SmBS1 for p+au running? (Steve Heppelmann)

9 Gain adjusted to MIP=100ch (50ch for layer3) Q1L1S4 FPS Status ADC ch Q1L3 Q1L2 Q1L1 Q2 Q3 1 Bad channel Q4 FPS Monitor: ADC Ch (1/4pC) Pedestal cut adjusted to reduce data volume >5*RMS from HV off pedestal => fixed to ch>9 FPS is running well

10 Radiation Damage to FPS SiPM Current operating voltage (beam off) Layer1 & 2 Red=near beam Green= middle Blue=far from beam 2 sets of 10 TLDs were installed around FPS/FMS Each stayed 4 weeks (under analysis) 3 rd set will be installed for pau layer3 Feb6 IV scan run# (~day) April16 Radiation damage to SiPM increased leakage currents from ~0.1uA to ~40uA some hit 52uA = FEEBd limit to measure current Gerard expect FEE HV problem at >100uA (can be modified)

11 FPS Pedestal PHYSICS voltage Q1L1S4 Pedestal PHYSICS voltage & beam off Feb9 FPS pedestal run# (~0.5day) April12 Pedestal Monitors: ADC Ch (1/4pC) Radiation damage increased pedestal RMS from ~1 to ~5ch

12 FMS-FPS correlation FPS layer3 slat# with >1/2 MIP hit Q1L3 Q3L3 Q2L3 Q4L3 StFmsPointMaker to find FMS point (PSU codes in STAR framework) StFpsRawHitMaker in CVS Normalized with FMS Y position distribution (otherwise spikes due to single cell cluster dominate the plot) Weaker but similar correlation seen in Layer1 & 2 Found 3cm misalignment for Q1/Q2 X position vs FPS layer1: FMS known ~3cm shift was not in DB yet More details at io/fms2015/ ABS(FMS point Y position[cm]) Adding FPS tag to FmsPoint coming soon

13 FMS from Survey South side shifted X=+32 mm from center line

14 Damage to Lead Glass 7.4 pb pb pb -1

15 Damage to Lead Glass Mass Peak Position: Day 92/Day 80 No observed effect on pion or eta mass position or pion mass resolution Delivered Luminosity: (40 pb -1 ) (error bars smaller than points) Pseudorapidity Pion Mass Resolution: Day 92/Day 80 Slope of pt Distribution Slope of pt distribution vs time: Slope INCREASES slightly! Day

16 Damage to Lead Glass: Pion Yields/Luminosity by Steve Heppelmann Pion Yield/Unit Luminosity decrease ~7%/day: Decreases by factor of for 17 /pb or -2.5%/pb -1. What gain loss does this correspond to?

17 Scaling of Pion Spectra Compare integral of pion yields over threshold for original and scaled pt spectra- Roughly factor of 5 difference: Decrease of trigger rate by 50% means decrease of gain by 10%. 0.9*pT Trigger Threshold For the small cell tubes (PMT gain ~V α with alpha = 4 or 8). To compensate for a gain loss of 10-20% implies a voltage increase of ~2-5%.

18 Voltage Compensation for Damage to Lead Glass over 200 GeV Running /pb -> factor of /pb Assume 200 /pb delivered during Run15 90 /pb p+p 300 /nb p+au x 200 = 150 /pb sampled ( /(pT slope*pmt gain exponent))**l ( /(5*4))**200 = 1.28 ( /(5*8))**200= 1.13 Increase voltage on small cells 13-28%

19 Conclusions FMS is performing well and is fairly stable. FPS Installed Stable running Monitoring radiation damage Correlation with FMS hits observed RP data read out with FMS Initial analysis shows FMS pion asymmetries correlated with RP triggers Must evaluate multiple events per crossing to say more We have achieved our goals for p+p transverse and (most likely) p+p longitudinal. Propose new voltage iteration before end of longitudinal running to compensate for gain loss and to prepare for p+au run. New iteration should adjust gain of innermost cells by % -> voltage change of +2-5%.

20 Backup Slides Day 92 / Day 80 LED Peak Ratios ~15% of small cells radiation hardened lead glass: needs no voltage adjustment