KAGRA Logbook

VAC (EY)

shinji.miyoki - 12:34 Monday 20 June 2022 (21191)

EYV/C leak start

[Kimura, Uchiyama, Miyoki]

We did EYC/V leak procedure.

10:00 : After checking the Y-arm GR flash by Ushiba-kun, Kimura-san closed GV_eya.

All TMPs and scrole pumps were turned off with proper GV/Diaphragm-valve closing around TMPs. Two back pressure prevention valves were set around EYC. The leak at 20 litter/min has started at the TMP unit on EYV around 11:00. About 1 Pa/min is now obtained. We need to enhance ~40 litters to finalize leaking until the next Monday morning.

Kimura-san noticed that EYC vacuum level unusual enhancement aroud the timing of the erathquake at 10:31 (@Ishikawa, 5+, M5.0).

Images attached to this report

Comments to this report:

shinji.miyoki - 5:59 Tuesday 21 June 2022 (21205)

At ~6:00 on 21st, the flow level reduced as the attached file (maybe ~ 16 litter/min). We will increase later.

Images attached to this comment

shinji.miyoki - 11:45 Tuesday 21 June 2022 (21207)

Uchiyama-kun increased the flow from ~ 16 litter/min to 40 litter/min around 10:00.

Unexpectedly, the pressure increase rate became 20 Pa/min, while 4 Pa/min when 20litter/min was set. We asked Kimura-san whetehr this situation is OK or not. Assuming 20 Pa/min, we can expect the full leak on next Monday.

shinji.miyoki - 7:21 Wednesday 22 June 2022 (21221)

The flow became 32 litter/min around 20:00 on 21st June, and 25 litter/min around 7:30 on 22nd June. Uchiyama-kun will increase it again today.

takashi.uchiyama - 13:22 Wednesday 22 June 2022 (21228)

Uchiyama

I adjusted amount of air flow to 40 L/min at 9:46 on June 22nd.

takashi.uchiyama - 16:59 Thursday 23 June 2022 (21253)

Uchiyama

I closed valves for the venting air at 14:30 on June 23rd to stop the venting.
The vacuum pressure of EY is 98,000 Pa (0.98 atm).

The venting will be resumed on the next Monday.