09.38 CC completed install of Bplast driver PCBs yesterday evening.
      All flat ribbon cables connected - all drain wires grounded
      PSU on but not enabled - return terminals grounded to PSU front panel ground
      SiPm bias off

      Water pressure and temperature OK
      FEE64 power ON

      DSSSD bias & leakage current OK - attachment 1

      FEE64 temps OK - attachment 2
      *except* aida02 ASIC temp which is known to be u/s

      All system wide checks OK *except* aida02 and aida03 WR decoder status - attachment 3

      WR timestamps OK - attachment 4

      ADC data item stats - attachments 5

      per FEE64 Rate spectra - attachments 6-7

      per 1.8.W spectra - 20us FSR - attachments 8-11

      ASIC settings 2024Mar27-11.25.32
       LEC slow comparator p+n FEE64s 0xa, n+n FEE64s 0xf

      BNC PB-5 pulser - attachment 12



10.45 CC returns
      bPlas ON

      ADC data item stats - attachments 13
       8x < 20k, max c. 310k

      per FEE64 Rate spectra - attachments 14

      per 1.8.W spectra - 20us FSR - attachments 15-16

      downstream DSSSD n+n and bottom left & right p+n FEE64s noisy


11.40 per p+n FEE64 1.8.L spectra - attachment 17
       aida09 pulser peak width 55 ch FWHM ~38keV FWHM - no change cf. before installation of bPas *except* aida16


12.00 Photos of snout, bPlas driver PCBs, cabling, grounding and PSUs courtesy JB - attachments 18-27

      N.B outputs of PN300 PSU at base of AIDA support stand are *not* ground ref'd - attachment 23


12.20 Slow comparator -> 0x64
      Pulser OFF
      All histograms zero'd

13.17 JB: returned from lunch. Current status of AIDA modules given by attachment 29.

15.55 While bPlast thresholds were being set the noise increased substantially.

16.51 Replaced mezzanine of aida14, reinstalled and biasing detector. Resulting for noise conditions in the detector given by attachments 30-33.

17.31 With a multimeter it was found that there is continuity between the snout and the frame.

18.50 We tried to disconnect the cables of the short side of the bPlast detector and all of the grounds. This seemed to show an open line OL on the multimeter and whence connecting the bPlast grounds back excluding the short side ribbon cable grounds, the multimeter still read OL. 
      We also tried to wedge paper between the short side ribbon cable of bPlast and the snout, but this did not work, the detector still reading continuity between the frame, booster board and snout. 
      The results after booting up the detector again are given by the attachments 34-36. 
      The noise condition is appreciably better than before with 12 out of the 16 FEE64 modules with sub 20 kHz rates.
      Disconnect the BB7 preamp. ground from the frame.

18.54 We powered up bPlast. The noise condition three FEEs got worse, aida01, aida11 and 06. The problem may be associated with downstream grounding. The results are given by the attachments 37-43. 10 out of the 16 FEE64 modules showed sub 20 kHz rates.

19.07 We turned off the power supply on the base of the snout support. PN300 Attachment 23. Rates did not change - attachment 44.

19.10 We turned off the mesytec PSU that is located in the bPlast NIM crate. No change was observed in the rates - attachment 45.

19.13 We turned off the R&SRMP4040 PSU that is located above the AIDA crate. And the noise situation did not change attachment 46.

19.22 Leaving the R&SRMP4040 PSU off we turned back on the mesytec PSU and PN300 PSU, attachment 47.

Summary:

It is clear that with no continuity on the short side we are able to reduce the noise back to the scenario where bPlast was not connected. However, powering bPlast introduced substantial noise in both DSSSDs that did not go away when turning all the PSUs off. There might be some hysteresis in the system (this is just speculation).

The situation is still fair considering that 10 out of the 16 FEE64 modules are in the sub 20 kHz rate level (good noise condition).

TO-DO for 11.04.2024

- Try bringing bPlast ground back to the PSU ground.

- Recheck the downstream detector bias and ground scheme.