1. Noise results from SR1 combined SCT barrel tests Summary of some initial results Alan Barr, UCL Pepe Bernabeu, Valencia

2. 2 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://indico.cern.ch/conferenceDisplay.py?confId=4146 http://pcphsctr02.cern.ch/cgi-bin/datadisplay.cgi

3. 3 Overall noise occupancy The noise occupancy is within specification 5x10 -4 Chip average noise occupancy Calibration run, asynchronous ROD triggered Run 2981, Scan 2 Hybrid temperature ~28C 1fC with cal correction factors Chip average noise occupancy Calibration run, asynchronous ROD triggered Run 2981, Scan 2 Hybrid temperature ~28C 1fC with cal correction factors

4. 4 B3B4B6B5 Run 2981, Scan 2, Module average NO 1fC with cal correction factors Noise Occupancy (before cosmics run) Temperature Hybrid T1

5. 5 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

6. 6 Noise in 3PG : ENC 3PG combined top + bottom Hybrid temp ~28 C B3 B4 B6 B5 RUN 2871 before long cosmics run

7. 7 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

8. 8 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

9. 9 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)

10. 10 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

11. 11 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 Hits per event Noise run 1 fC uncorrected (trim target) Gaussian Tanaka et al Cosmics run

12. 12 Grounding schemes 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 #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 line red blue Tanaka et al

13. 13 Noise stability 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 Before cosmics run (2981) B3 After cosmics run (3102)

14. 14 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)

15. 15

16. 16 Noise occupancy at end of test period Run 3102Top SectorBottom Sector B34.56e-54.14e-5 B43.41e-54.03e-5 B54.17e-54.27e-5 B66.63e-54.95e-5 Overall average 4.13e-5 Similar to single barrel tests

17. 17 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

18. 18 Backups

19. 19 Noise physics run at end of cosmics

20. 20 Heater tests Reference 1 Reference 2 ON Switching

21. 21 Chip average noise occupancy Calibration run, asynchronous Run 2981, Scan 2 Hybrid temperature ~28C 1fC with cal correction factors Chip average noise occupancy Calibration run, asynchronous Run 2981, Scan 2 Hybrid temperature ~28C 1fC with cal correction factors

22. 22 Difference in ENC noise 3PG B3 B4 B6 B5 (Combined Top & Bottom Sectors Run) minus (SCTDAQ reference) Hybrid temps ~28C for both

23. 23 B3 Standalone (2979) B3 with other barrels (2981)