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Commissioning and Operation of the CMS Tracker analogue optical link system at TIF with CMSSW:

Commissioning and Operation of the CMS Tracker analogue optical link system at TIF with CMSSW:. R.Bainbridge, A.Dos Santos Assis Jesus, K.A.Gill, V. Radicci. Commissioning of the Optical Link: 5189 laser diodes were tested in the slice test at TIF

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Commissioning and Operation of the CMS Tracker analogue optical link system at TIF with CMSSW:

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  1. Commissioning and Operation of the CMS Tracker analogue optical link system at TIF with CMSSW: R.Bainbridge, A.Dos Santos Assis Jesus, K.A.Gill, V. Radicci

  2. Commissioning of the Optical Link: • 5189 laser diodes were tested in the slice test at TIF • each laser was tuned, to determine the optimal gain and bias setting, during the standard commissioning procedure with the CMS Tracker online software XDAQ and the analysis software RootAnalyser. • A commissioning run is performed for each temperature: 15,10,0,-10,-15 0C. • This analysis is performed using the offline commissioning CMSSW framework (by Rob) • Almost completed: • Validate CMSSW procedure for the basic configuration of the Optical Link • Debug/test the code  Check using TIF data • Compare CMSSW – Root Analyser • Compare the performances of different Subsystems (TIB TOB TEC) • Study performance and detailed temperature effects (nominal 150C, 100C, 00C, -100C, -150C) • Ongoing: • Propose new histograms and variables for link performance (E.g. link noise contribution at different bias values... ) • Propose a standard procedure for monitoring of link performance during the Tracker operations (Reliability and radiation effects)

  3. Analysis Procedure: Package: /CMSSW_1_4_0/src/DQM/SiStripCommissioning: RU file stored on Castor + Cabling from Online DB /SiStripCommissioningSources/src/OptoScanTask.cc (RB) /SiStripCommissioningClients/src/OptoScanHistograms.cc (RB) ( /SiStripCommissioningAnalysis/src/OptoScanAnalysis.cc) Source_run#.root For each Gain produces: 1) Summary Histos_run#.root (not yet implemented!) 2) debug_7531.log file GainSummaryPlot.cc (VR) *Actual Gain : 0 *LLD bias setting : 21 *Measured gain [V/V] : 0.69225 *'Zero light' level [adc] : 28.9667 *Link noise [adc] : 0.179505 *Baseline 'lift off' [mA] : 8.56697 *Laser threshold [mA] : 6.69421 *Tick mark height [adc] : 553.8 *Actual Gain : 1 *LLD bias setting : 20 *Measured gain [V/V] : 0.75632 *'Zero light' level [adc] : 30.85 *Link noise [adc] : 0.357071 *Baseline 'lift off' [mA] : 8.34694 *Laser threshold [mA] : 5.29931 *Tick mark height [adc] : 605.056 ...................... *Optimum LLD gain setting : 1 Summary plots .gif .root

  4. Zero Light Level Laser Threshold = Lift Off –W/2 Tick Mark hight = W * Base Slope Measured Gain = Tick Mark * (1/0.8) * (1.024/1024) Best Gain ~= 0.8 Bias setting = Lift off + 2 FED output “Tick” “Base” W 50% range Overlapping range Fit to points within the 20% and the 80% of the range W/2 Laser Bias (I2C) 1 count = 0.45 mA Lift Off Laser Current = (Laser Thr * 0.45) mA Coded by Rob

  5. Variables Monitored: • Best Gain • Bias Setting • Measured Gain • Base Slope • Tick Mark hight • Zero Light Level • Lift Off • Laser Thresold

  6. Few Plots

  7. TIB+TOB+TEC @ -100C - Run 11309 @ different gains for different subsystem Bias Setting Measured Gain Target Gain = 0.8 Mainly lasers @ Gain = 1

  8. TIB+TOB+TEC @ -100C - Run 11309 Independent on the subsystems and Gains Base slope Tick Height (Laser + LLD) (Laser + LLD + APV) Slope vs Tick W = (Slope/Tick)-1 Input tick to link (=APV output tick) Different behavior TIB, TOB, TEC due to the different low voltage drop (see A. Venturi talk)

  9. TIB+TOB+TEC @ -100C - Run 11309 Zero Light Level  Trim DAQ value This distribution strongly depends on the temperature of each Fed channel. • - Related to the AOH temperature • Double peak in TIB modules • Structured peak in TOB and TEC • TOB always higher • To compare with the distribution from the production Laser threshold (mA) Baseline lift off (mA) @ Gain 0 Gain Correlated to Laser th = Lift off – W/2

  10. Digression: “Why double peak in laser th distribution?”

  11. TIB Double Sided TIB Single Sided Ccu26 ccu28 ccu30 Ccu27 ccu29 ccu31 Fiber 1 Fiber 2 Fiber 3

  12. Laser temperature “Tracker Map”: (fiber #3 @ gain 3 @ T=150C) TEC Disks • “CMS Tracker Map Visualization” tool used here to map the laser temperatures: • - TOB is hotter • - two different temperatures for TIB modules (green and yellow in the map)  double peak in the TIB distribution TID Disks TIB Layers TOB Layers Laser Threshold distribution Color scale from Red = hot to Blue = cool - Powerful tool also for mapping the tick height, base slope… - Interesting results will come from the correlation between Tick and Laser Temperature CERN, 9th October 2007 12 V. Radicci CERN, 9th October 2007 12 V. Radicci

  13. CMSSW vs RootAnalyser:

  14. CMSSW RA 1) Comparison of Best Gain chosen for each laser (T=-100C) Difference channel by channel between Best Gain(CMSSW) – Best Gain (RA) 3.4% with diff>0

  15. CMSSW RA 1) Comparison of Bias setting chosen for each laser Difference channel by channel between Bias (CMSSW) – Bias (RA) 16% with diff>0 mainly ±1

  16. Due to the different gain Good agreement Robust performance of new code

  17. Measured Gain @ Selected Gain  comparison with the simulation

  18. T=100C T=150C T=-100C T=-150C T=00C Range 0.62 V/V – 0.96 V/V independent from temperature in Agreement with simulation! Gain spread looks reasonable. Usual effect of increased gain with higher temperature. Values to be compared with simulation

  19. Temperature dependence • all distributions are fitted with a Gauss function, the mean and the error are plotted as a function of Temperature

  20. The parameter have to be determined by comparing with other measurements: PLC, DCU Nominal cooling temperatures !! - Laser threshold current is temperature dependent. - Different values with gain and subsystems at the same nominal temperature! - The current @ the laser threshold (Ith) can be used to evaluate the actual laser temperature T according its known exponential behavior:

  21. ΔT evaluated from Ith for different values of • In order to compare the AOH temperature and • the temperature of the cooler or of the air (PLC measurements), • the temperature of the sensor and of the hybrid (DCU readings) • we can considering the temperature variation ΔT=(T1-T2), measure on the same element (laser, hybrid…), for different experimental condition. TWarm – T0 TWarm – T+10 TWarm – T-10 TWarm – T-15

  22. A. Venturi To be checked!!!!

  23. Now “the laser is a good thermometer” !!! • Note large ΔT over nominal

  24. Effect of T on link gain and tick mark height Laser alone (Laser + LLD) Tick height at FED (Laser + LLD + APV) W = Tick Height / Base Slope Input tick to link (=APV output tick) Measured gain prop to Tick

  25. Fit slope: G0: -0.24 G1: -0.26 G2: -0.27 G3: -0.27 Decrease = (0.55±0.02) % / 10C Fit slope: G0: -2.4 G1: -3.1 G2: -4.4 G3: -5.8 Decrease = (0.49±0.03) % / 10C • Gain change seems dominated by laser • Individual lasers vary more and do not necessarily follow average trace • APV tick is constant!

  26. Particular behavior of the Zero light level an explanation could be considering the fed temperature channel by channel Fit slope: G0: 0.080 G1: 0.084 G2: 0.086 G3: 0.086 Decrease = (1.0±0.1) % / 10C Fit slope: G0: 0.18 G1: 0.19 G2: 0.18 G3: 0.18 Decrease = (1.0±0.1) % / 10C

  27. Conclusion • Links commissioning software/analysis in use on TIF data • CMSSW code stable • New parameters included • Laser threshold, noise, tick input height • Able to check out detailed effects • Move development effort now onto details of performance (e.g. noise) and monitoring (Ana talk)

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