Uchiyama
Pumping down of IY started at 9:35 by the root pump at between BS and IYC.
The vacuum pressure reached 0.1 atm about 3:35PM and one additional root pump was started pumping.
Changes of vacuum pressure are followings.
9:35 1atm, Pumping down started
10:35 0.77 atm
11:35 0.56 atm
13:10 0.30 atm
14:00 0.21 atm
15:15 0.11 atm, One additional root pump at between IYA and IYC was started pumping
15:35 0.09 atm
Summary of monitoring IP of ITMY during pumping down.
Followings are the necessary steps for centering IP position.
IPL: -24800 steps
IPT: -22400 steps
IPY: +6400 steps
Note:
Figure 1 shows the trend of GAS position and BFV during pumping down.
According to the trend of BFV, total amount of height change is about 0.65 mm.
