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Full report of tests made on mockup with M5R4 with remarks

Full report of tests made on mockup with M5R4 with remarks. Part 1 Cross-talks problem. Problem:. What the reason that M5R4 is so differ from M3R4 (WPC) on both fundamental characteristics: HV-plateau and cross-talks?

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Full report of tests made on mockup with M5R4 with remarks

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  1. Full report of tests made on mockup with M5R4 with remarks Anatoly Kashchuk

  2. Part 1 Cross-talks problem Anatoly Kashchuk

  3. Problem: What the reason that M5R4 is so differ from M3R4 (WPC) on both fundamental characteristics: HV-plateau and cross-talks? Remind: cross-talks within bigap ‘pad-to-pad’ ~1-2% in both type of chambers (I have measured by direct coincidence) Cross-talks’ vs. HV are anomalous, see plot below. Cosmics Self-triggering (AND logic) Remarks: it can be due to very large pulses (track parallel to wires) or micro-discharges outside the chamber (water closed on HV-board). Nevertheless, each type of chambers at similar conditions in measurements. Anatoly Kashchuk

  4. M5R4#39LNF Cross-talks between super-strips within one bigap vs. HV by direct coincidence per 100sec I HV(V) I&II Ratio I/I&II Anatoly Kashchuk

  5. Typical Measured at asymmetric HV In reality will be symmetric. Slope increased. Anatoly Kashchuk

  6. Scope shows pulse multiplication at high HV HV(1+2)=2550 / HV(3+4)=2750 See next slides which show contribution Anatoly Kashchuk

  7. Q. Cross-talks via capacitive coupling or pulse multiplication • or something else? • Something else (!) • Multiplication cancelled (see new measurements), ‘something’ dominates • Note: multiple pulse cancellation is shown in one super-strip # I here Anatoly Kashchuk

  8. Note: multiple pulse cancellation is shown in super-strip # II Anatoly Kashchuk

  9. Note: multiple pulse cancellation is shown in super-strip # III Anatoly Kashchuk

  10. HV scan in one gap at others un-powered (X-talks contribution study) There is no capacitive coupling between gaps (!), but what there is? Gap3 dominates (triggers gap1 and 2) Gap 2 triggers gap 3 mainly Reason: asymmetric design of the detector ground Anatoly Kashchuk

  11. I Ramp Z imperfection 10% fraction is enough to produce hit (depends on HV) Ramp New type of cross-talks ‘gap-to-gap’has been found Reason: Impedance of the detector ground switches detector currents (return) to other gaps (mistake in the design of ground in front of FEE) Note: 1. Z is inductive (assuming 1nH, one can get 60 mΩ at 10MHz which is more than contact resistance, also spectrum much higher in front of FEE); 2. Z provides ringing of very high frequency, so fraction of pulse in neighbor channel is not an opposite polarity, as shown for simplicity. Anatoly Kashchuk

  12. Measurements ‘count vs. HV’ in horizontal and vertical positions of the chamber X-talk (gap-to-gap) ~(30-40)% in range of 2650-2750V Usually HV will be equal on both bigaps and X-talks will be higher Anatoly Kashchuk

  13. M3R4 (PNPI) performance has been improved by separation of the detector ground ‘bigap-to-bigap’ (cut along chamber) Final result Anatoly Kashchuk

  14. M3R2W (CERN) shows negligible ‘bigap-to-bigap’ cross-talks measured at TH=7fC, in other chambers TH=15fC No connections of cathodes in between in this chamber, except on SPB, i.e. FEE Anatoly Kashchuk

  15. Part 2 Cosmics measurements Other remarks Anatoly Kashchuk

  16. Note: in order to prevent long discussions… all measurements on mockup have been done using Rafael’s software starting from boards and finishing of cosmics Nothing Andre’s used Report sent by Andre to Giovanni 24/09/06 full mistakes, e.g. thresholds. Absolutely wrong strategy for final tests of chambers has been proposed in this report by Andre… Anatoly Kashchuk

  17. FEE noise spectra in log scale CAEN2527=ON Bad Bad Bad Anatoly Kashchuk

  18. CAEN2527=ON Bad Bad Bad Anatoly Kashchuk

  19. Noise count per 1s M5R4#16 at TH=7fC@9mV/fC - too big noise in the 1-st board Noise count per 1s M5R4#19 at TH=7fC@9mV/fC - too big noise in the 1-st board Anatoly Kashchuk

  20. M5R4#16 Cosmics: HV=2650V all gaps at TH=15fC@9mV/fC Width 25ns Anatoly Kashchuk

  21. M5R4#19 Cosmics: HV=2650V all gaps at TH=15fC@9mV/fC Width 25ns Anatoly Kashchuk

  22. CAEN2527=OFF M5R4#16 Better Better Better Anatoly Kashchuk

  23. CAEN2527=OFF M5R4#19 Good Good Good Anatoly Kashchuk

  24. Noise count per 1s M5R4#16 at TH=7fC@9mV/fC previous3 CAEN2527=ON with HV=2650V all gaps CAEN add noise Anatoly Kashchuk

  25. Noise count per 1s M5R4#19 at TH=7fC@9mV/fC CAEN2527=ON with HV=2650V all gaps CAEN add noise Anatoly Kashchuk

  26. M5R4#16 Cosmics (very big statistics): HV=2700/2450V all gaps TH=15fC Mean:289468.50 RMS:7558.96 Ratio:0.03 (X-talks=3%) Anatoly Kashchuk

  27. M5R4#16#19 Reason: unknown TH=7fC TH=12fC TH=15fC Disappeared at TH=20fC only Anatoly Kashchuk

  28. M5R4#16 HV=2650V TH=7fC Study of the anomalous noise Looks as I2C-cable has influence A=00 out A=01; A=02 A=00 std connection A=00; A=01 out A=02 connected only Anatoly Kashchuk

  29. Study of the anomalous noise I2C-cable grounded on right side Anatoly Kashchuk

  30. M5R4#16 HV=2650V TH=7fC Study of the anomalous noise I2C-cable grounded on left side near LV-cable Anatoly Kashchuk

  31. M5R4#16 HV=2650V TH=12fC Study of the anomalous noise 3 additional LVDS-cables (screens were added only) Anatoly Kashchuk

  32. M5R4#16#19 HV=2650V TH=15fC Study of the anomalous noise 3 LVDS-cables ‘screen only’ added Problem fixed Resonance ! Anatoly Kashchuk

  33. M5R4#16#19 HV=2650V TH=15fC Statistics with internal counters Mean:3530 RMS:301 Ratio:0.09 (9%) Noise count ~10Hz at TH=15fC Anatoly Kashchuk

  34. M5R4#16 HV=2650V TH=15fC Statistics during night Mean: 277368 RMS:5998 Ratio:0.02 (2%) Anatoly Kashchuk

  35. M5R4#16 HV=2650V TH=15fC Noise count: 10.6Hz; Non-uniformity ~32% Good Anatoly Kashchuk

  36. M5R4#19 HV=2650V TH=15fC Noise count: 10.8Hz; Non-uniformity ~26% Good Anatoly Kashchuk

  37. M5R4#16 HV=2650V TH=12fC 12.71 4.05 0.32 Good Noise count ~13Hz at TH=12fC Anatoly Kashchuk

  38. M5R4#19 HV=2650V TH=12fC 12.67 3.94 0.31 Noise count ~13Hz at TH=12fC Good Anatoly Kashchuk

  39. Remarks: Resonance in ground loop has been found and shifted out of FEE bandwidth; Anti-resonance wires and points for connection (at least 5) along FC for reduction of the equivalent inductance of all cables attached to chamber in order to be able in pit move resonance out of FEE bandwidth (very important issue); Decoupling capacitors must be in all these lines; Point for grounding of the LV-cable screens must be added on FC near LV-port (missing); Decoupling capacitor must be there; Too long screws in HV cables, no/bad contact for grounding screen of the HV cable Anatoly Kashchuk

  40. Measurements on cosmics 10 chambers of M5R4 both FI and LNF in vertical position of chambers (on mockup) have been tested (as requested by Giovanni) Anatoly Kashchuk

  41. Note: Resonance moved out of FEE bandwidth to higher frequency by reduction of the inductance Remind: negative CARIOCA has lower bandwidth (~30MHz) than positive CARIOCA (~50MHz) Anatoly Kashchuk

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  47. Not measured (due to various problems in FE boards) chambers #14FI and #26LNF (channel 2 missing) These problems were not detected by Andre’s SW at LNF and chambers were arrived to CERN for installation with mistakes Anatoly Kashchuk

  48. Anatoly Kashchuk

  49. Additional slides in chronology (problem of cross-talks was discussed already in Part 1) Anatoly Kashchuk

  50. One bigap at 0V, second scan without noisy CAEN 2527 (OFF) Result the same…. Cross-talk source unknown X-talks in center dominate at any HV Count ‘profile’ at HV=2650V Count ‘profile’ at HV=2800V Anatoly Kashchuk

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