Helium leak checked the joints listed below via the new Inficon UL1000, backing vertex turbo, while X/Y-BM turbos were valved out. The background started at 6e-9 mbar-L/s and drifted to 1.4e-8 mbar-L/s after valving out other two turbos, likely from cross talk due to relatively high volume pressure. No leaks found above this background.

• three NEG reducer flanges on OMC
• IP4 GV on OMC
• TMDS flanges and GVs on BSC 1,3 doors
• (existing) TCS viewport flanges on BSC 1,3 doors
• (existing) HAM2-E bottom-middle viewport flange
• ESD flangles & feedthroughs on BSC 1,3 chambers
• PT-120 valve & flanges on BSC 2
• YBM turbo isolation GV
• two blanks that replaced i-LIGO RGA port on BSC 7,8
• viewport flange on HAM5-N door