Grounding implemented

• Each FEE given direct connection to heavy duty earth bar via adaptor board lemo ground
• Earth bars are then connected to platform ground on AIDA frame
• Photo of grounding - attachment 1
• Improvements not as large as expected from previous experience though
  • Particularly in the n+n side where widths still appear awful
• While implementing the grounding it was noticed the ground lemo socket on FEE7 was damaged and no longer gripped onto a lemo cable
  • It was noted that it would need changing at some point but continued with it for the time being
• Jumper configuration was n+n LK1-4 all on, p+n LK2-4 all on

p+n widths

• Compared to the width with no grounding the FEEs for the first DSSD (First 6) range from no change to slightly worse
• 1.8.L spectra - attachment 3

n+n widths

• Widths still very large
• Width for 8 is around 500
• 1.8.L attachment 2

Additional info

• Statistics - attachment 4

Jumper optimisation

• Went to our previously found optimal jumper configuration for the trips
• n+n LK1 only
• p+n LK 2 and 4 on all FEE
• p+n LK3 on non isolated cables (PCB ground on lower middle cable and n+n side bias on top middle cable)
• While changing the jumpers we also swapped out the damaged adaptor board on aida07 for a new one
• Saw an improvement for most FEEs

• Unfortunately saw no improvement for the n+n
• We event tested having the pulser only going into a single FEE (aida08)
• Still have a width of 622 for that FEE
• To compare FEEs we have layout 1 - attachment 5
• Layouot 1 on a common timescale - attachment 6
  • Note that the rate is typically dominated by a single strip or a couple of strips within a FEE
  • Many channels are just showing the pulser rate 25Hz
• p+n  1.8.L attachment 7
• p+n waveforms attachment 8
• n+n waveforms attachment 9
• Testing the noise on the n+n strips we observe noise with slow comparator set to 200 (2MeV)
• Meanwhile the p+n strips are silent at 0x64 for the most part.
• DAQ left running overnight with 0x64 on ASIC settings to see if we observe any alphas

Plan for the day

• Test daisy chaining the n+n across to the other n+n strips
  • Currently the n+n braid is only plugged into either aida06 or aida08 (depending on DSSD)
  • All of the jumpers are however grounded
  • Will still test
  • May investigate also trying this on LK3 on adaptors for aida01 and aida03
• Observe the output of the new sum inverter on the scope to check for variation in amplitude