- On Thurdsay June 4th the EHDT beamline section was vented by Vacuum Group so that they could install a new pump
- After pumping down again a leak was found at the BD front flange seal around the top of the seal
- The RH clamp and Helicoflex seal were removed and an o-ring seal was installed with a band clamp
- The EHDT section was pumped down and leak check performed - no leaks

- While the EHDT section was vented both flanges were measured and found to be in spec (see attached PDF)
- The clamp jaws were also checked and were in spec (see PDF)
- Seal was inspected: delta fully crushed at bottom, but a visible ridge remained around the top

- A meeting was held on June 5, with Grant Minor, Isaac Earle, Keith Ng, and Bill Paley in attendance.  Meeting minutes copied below:

Meeting Summary:
- We suspect the leak is caused by inadequate seal compression
- The leaks on this installation may be because of the new batch of seals which are thinner (by ~0.006") and have a less pronounced delta  (all the successful installations on 2A are using the old batch of seals)
- It is possible that the recent bench tests performed with the new batch of seals also had very small leaks that were not detectable with the "Star Wars" leak detector
- The clamp must be modified to achieve the manufacturer seal compression spec (currently 0.020" short)
- We will not pursue testing of clamp closure beyond the point where the jaws are concentric (0.685" stop-ring)

Actions:
- As a temporary measure a seal from the old batch will be installed at the e-dump next Monday (Keith, Isaac, Bill)
- Modified clamp jaws, to achieve design seal compression, will be designed/ordered (Keith), and bench tested (Keith, Isaac/Bill)
- We will pursue purchase of a new leak detector for the lab.  If leak checking is required before then we will borrow a modern detector from Vacuum Group  (Isaac)
- If the old batch seal installation at the beam dump is leak tight, we will still switch to a new seal and modified clamp jaws once development is complete and an opportunity to swap presents itself (Isaac)