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Noise results from SR1 combined SCT barrel tests Summary of some initial results. Alan Barr, UCL Pepe Bernabeu, Valencia. Data Sources. Online calibration scans ROD and TIM triggered Physics mode scans + offline analysis Triggered from pulser Analysis:
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Noise results from SR1 combined SCT barrel tests Summary of some initial results Alan Barr, UCLPepe Bernabeu, Valencia
Data Sources • Online calibration scans • ROD and TIM triggered • Physics mode scans + offline analysis • Triggered from pulser • Analysis: • Online analysis of calibration scans • Offline noise analysis & monitoring http://pcphsctr02.cern.ch/cgi-bin/datadisplay.cgi http://indico.cern.ch/conferenceDisplay.py?confId=4146
Overall noise occupancy • The noise occupancy is within specification Chip average noise occupancyCalibration run, asynchronous ROD triggered Run 2981, Scan 2 Hybrid temperature ~28C 1fC with cal correction factors 5x10-4
Run 2981, Scan 2, Module average NO 1fC with cal correction factors NoiseOccupancy(beforecosmics run) Temperature Hybrid T1 B3 B4 B5 B6
Comparison to previous data • Needs to be corrected for time biased, temperature etc • The noise occupancy • Seems a little higher for single barrel test than macroconstruction • more so for barrels 3 and 6 • also perhaps a little higher for all barrels on than for single barrel tests • ENC input noise (from 3 point gain) • perhaps 40-50 electrons greater than macroconstruction results after temp corrections • ENC input noise within 5 electrons of same-temp module assembly values
Noise in 3PG : ENC 3PG combined top + bottomHybrid temp ~28 C B3 B4 B5 B6 RUN 2871 before long cosmics run
Thresholds • RMS noise occupancy decreases when using calibration-capacitor-corrected “Response Curve” 1 fC threshold • As we would hope • No change in mean NO • From offline analysis
External Pickup? • No hint so far of extra noise occupancy due to TRT • Offline analyses in progress • Likewise for heaters: • Runs: Off / On / Switching / Off • Noise occupancy
Self pickup? • Pickup from ABCD readout visible at end of pipeline • (±synch) double trigger noise test • Factor of ~1.8 increase over several time bins at end of pipeline • Small effect when averaged out over 400 time bins (for 100kHz triggers worst case)
Dependence on trigger rate • Physics run: pulser rate varied from: • 5 Hz • 50 Hz • 500 Hz • 5k Hz • 50 kHz • No evidence of increase in noise occupancy • Events sizes the same • Plots look very similar
Correlations • No increase in noise occupancy observed when using synchronous triggers • No correlations seen so far between noise hits within chips (“occupancy per event”) • No correlations seen so far between hits on different modules • Except cosmic tracks! • Full correlation analysis in progress (Ewa) Hits per event Noise run 1 fC uncorrected(trim target)Gaussian Tanaka et al Cosmics run
Grounding schemes #chip=(252+216)x12=5616 (2 modules are masked online) Run 3084 3085 Shorting out in Mean 4.57x10-5 4.57x10-5 RMS 3.42x10-5 3.39x10-5 lineredblue • No significant change in the noise occupancy when we change the grounding scheme. • Grounding scheme in SR1 is not “final” • Final scheme only available in the pit Tanaka et al
Noise stability B3 Before cosmics run (2981) • Long runs exist to check overall stability in time • Calibration runs show expected decrease in NO after long period biased • Also seen in “physics” runs • Consistent with single barrel tests B3 After cosmics run (3102)
Noisy strips? • A handful of strips cut out for offline analysis (of order ten) • In addition to channels masked online • In some cases individual strip noises change between runs by factors ~3 • Not understood • Poor individual channel trim? • Usual modulation across module • Noise occupancy higher towards centre of chips • Link 1 noisier than link 0 • (Both as they has always have been in module tests)
Noise occupancy at end of test period • Overall average 4.13e-5 • Similar to single barrel tests
Overall conclusions • Unless small increase in Noise Occupancy seen for B6 or B3 scales badly with #modules we are in good shape for noise • Ultimate test will be using final grounding scheme in the pit
Heater tests Reference 1 Reference 2 Switching ON
Chip average noise occupancyCalibration run, asynchronous Run 2981, Scan 2 Hybrid temperature ~28C 1fC with cal correction factors
Difference in ENC noise 3PG (Combined Top & Bottom Sectors Run) minus (SCTDAQ reference) B3 B4 B5 B6 Hybrid temps~28C for both
B3 Standalone(2979) B3 with other barrels (2981)