UCSB cold box noise issue

1
UCSB cold box noise issue
Before
After

• High noise on all 8 slots tested
• Noise apparently caused by bias leakage current
  running through common ground on UTRIs.
• Grounded hybrid-to-UTRI adapters to cold box
  plates.
• Grounded slotted cold plate through power supply
  to wall ground
• Provided shorter path to ground for bias leakage
  currents
• Noise reduced on all slots enough for defects to
  be seen.
• All slots have increased noise (2-4 counts) on
  chip edge channels.