Dear all,

After the incidences reported yesterday and the diagnostic remotely done (where we could narrow down the root cause to the edge-welded below at the Linear stage of the arm Nr. 6 - 2.4 mm CVD diamond], we confirmed this as a fact during the schedule access today. Here is a succint summary of what happened.

1. Although planned for 9:00, we could only enter the tunnel past 10:15 due to some issues for the accurate release of the XTD1 tunnel interlock, in such way that the use of the XHE2 elevator could be used.
2. The first action was confirming the first hypothesis. The result of a direct He-leak test shown a leak rate up to 5*10-6 mbar*l/s, which was consistent with the observation from yesterday. No other leak was found.
3. After securing the vacuum integrity of the lateral sections, venting the long sector took some time.
4. We also had some issues with the vacuum connections of the affected actuator, but eventually it could be eventually removed.
5. A first evaluation of the 2.4 mm CVD diamond, no major damage is evident and the chances of reusing are high (at least at first sight).
6. Also, the repair of the leaky part (or better said, its eventual replacement) seems feasible, and would only depend on finding a similar bellow equipment. XRO is working already on this.
7. The vacuum system could be recover relatively fast to an extent where a general leak test could be performed again. No further leaks were found.
8. After the removal of the arm 6, and the reconfiguration of the pneumatic system, we tested several time (in air and in vacuum conditions) that not having the arm 6 wouldn´t block the use of the solid attenuator. Also XRO check/is checking all the possible implications for the "normal" operation of the beamline.
9. At 13:30 we communicated with BKR and later with the PRC to provide feedback on the progress.
10. At 14:15 we confirmed that we were leaving already the tunnel, so the tunnel search could be triggered.
11. Around 14:30, the SA2 vacuum OK signal was released and confirmed by BKR operators.
12. In conclusion, the time envelope  of effective work (4h) was achieved.

At this moment, the sector vacuum level is recovering positively and the average pressure is in the 5*10-8 mbar after 2,5 hours of pumping the the ion pumps, which is a good indication of the overall success.

With best regards,

R. Villanueva & B. Dickert.