22/04/15

1230: Solved problem (empty spectra despite changing modules) with nnaida5 noted in previous progress update.

          During Feb tests, nnaida5 was very noisy compared to other nnaida => switched it to medium energy range to effectively turn it off.

          This was saved in the default setting so this same configuration was loaded on startup.

          Changed back to low energy mode, giving nnaida5 equally good performance as other nnaida, and altered system settings save file.

1630: Added heavy duty ground cabling to the copper blocks holding the adapter PCBs in loop around inner FEE modules with connections out to further out ones.

          Removed PC-S copper braids with clippy ends.

          Put electrical tape over the surrounding aluminium cooling crate to prevent electrical contact with that.

          Using BB18 detector 2977-20 connected to FEEs 1, 3, 5, 8 using kaptons labelled E, B, F, G respectively.

          The FEEs connected to the detector saw much higher low-energy noise levels and typical FWHM of pulser peak increased by ~100ch to ~250ch.

          Reduced shaping time and increased thresholds but saw no improvements.

          Refitted PC-S clippy copper braids in loop around inner most FEE modules and saw all pulser FWHM reduced to the ~130-150ch we saw during Feb tests (see attachments 1-4).

          Suggests poor electrical connection between adapter PCBs and copper blocks.

1840: Added 4 new FEEs (nnaida25+26, 29+30) to system for use with new adapter PCBs accepting LEMO inputs from BigRIPS DAQ.

          Edited /MIDAS/config/TclHttpd/aidas1@8015/startup.tcl to make system contain new FEEs.

          Created new ASIC setting save file @ /MIDAS/DB/2015Apr22-extraInput.

          nnaida25,29 have positive pre-amp polarity and nnaida26,30 have negative pre-amp polarity (along with other associated setting).