Matteo, Yuhang, Marc, Aritomi

Today the TAMA vacuum system has been partially recovered.

The vacuum level before starting the recovery was 22mbar both in the arm as well as in the central area and in the South end tower.
The status of the vacuum pumps was as follow:

• BS: rotary and turbo fine and working
• South near: scroll and turbo fine and working
• South mid: scroll and turbo fine and working
• South end: scroll fail and turbo off

All the pumps were isolated by gate valves. The gate valve at South near between arm and central area was closed and the arm+South end was evacuated using the big movable rotary pump.

After reaching a pressure of about 1e-2 mbar, the movable rotary pump was removed and the gate valve between the arm and the South near was opened, as well as the South mid gate valve between the arm and the turbo pump. After performing this operation the pressure in the arm reached 2e-5mbar at South near and 1e-4mbar at South end.

After this also the central area was evacuated using the movable rotary pump and using the same procedure just described, the central area was evacuated to a level of 1e-3mbar. At that time, since the pressure in the central area and in South near was almost the same, the big gate valve between central area and south arm was opened.

Before leaving the vacuum level was about 1e-5mbar in the central area and 8e-5 in South end.

All the vacuum pump are working properly with the exception of the South end dry pump which is still giving error message. The turbo pump at South end is off and isolated from the arm.