David Wang wrote: |
All water circuits are by passed on the top of TM3. Water pumps and vacuum turbo- pumps are started. Everything is ready for TM3 camera sparking check.
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Wednesday November 30st: <br>
- 3 cameras (1 UV and 2 regular cameras) were installed in the Service cap and the module was pumped down. 1 UV and 1 regular were placed on the East side of the module, aiming to water lines entering the Service Tray; 1 regular camera was placed on the South side of the module, aiming at the bottom of the blue insulators.
- started pumping down. <br>
Thursday, December 1st: <br>
- 1st HV test done. TM3 started sparking above 20kV. The cameras responses were consistent with the sparks. However, the screens were flickering and it was not clear if the responses were due to electromagnetic interferences; or due to cameras' gain change caused by high intensity light due to sparking.<br>
- added helium using the regulating valve. same results were found; <br>
Friday, December 2nd: <br>
- vented the module. <br>
- shielded the cameras' cables with aluminum tape. <br>
- removed 2 blue insulator (EE and HS) and shortened them by 1". They were found too long: HS blue insulator touching the horizontal HV water line; and the EE blue insulator at 2-3mm far from the HV water line; re-installed both shortened blue insulators.<br>
- changes the location of the cameras: 1 regular camera taped to the UV camera were placed South, aiming at the bottom of the blue insulators; 1 regular camera was kept on the East side of the module, also aiming at the bottom of the blue insulators. <br>
- started pumping down. <br>
Saturday, December 3rd: <br>
- 2nd HV test was done, with cameras' installed as mentioned above. results were consistent with the first test results. <br>
- added helium. results were the same. <br>
- vented and changed the location of the cameras: 1 regular camera taped to the UV camera were placed at the top of the Service Tray (South-West corner) aiming down the Service Tray; 1 regular camera was kept (its setup was not touched at all) on the East side of the module, aiming at the bottom of the blue insulators. <br>
- attempted to pump down, but the module was leaking. reopened the flanges, cleaned them, attempted again to pump down, but it showed a bigger leak. <br>
Sunday, December 4th: <br>
- the third attempt to pump down was successful (without reopening the module!). <br>
Monday, December 5th: <br>
- did the 3rd HV test with the cameras installed as described on December 3rd. same results as before were seen. <br>
- again helium was added and same results were noticed. <br>
- stopped pumps and prepared for venting to relocate the cameras lower in the Service Tray.
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