User name C. Armstrong
Log entry time 12:36:20 on July 9,1999
Entry number 14091
This entry is a followup to: 11061
keyword=HMS Cerenkov signal groundingI revisited the HMS Cerenkov grounding issue. The top pedestal plots below are with the cut-ground cables. With these cables in place, the signal at the fan-in (into a scope) (i.e., at the end of the cables) looks pretty horrible -- low amplitude and funny shape.
The lower ped plots below are with properly grounded cables. The peds are still noisy, but not really more than before. The signal at the fan in with these cables looks fine.
Beni suggested looking at splitter-to-rack grounding, which can be problematic with the painted versions of splitter. There appears to be low impedence (couple of tenths of an Ohm) for our (unpainted) guys, so no prob there.
I'm going to stick with properly grounded cables. They have not yet been timed into the trigger.
FIGURE 1
