[Uchiyama, Nakagaki]
We have changed the operation thresholds of the center's GV closure devices (3 locations) to the following values.
- [GV BSX & BSY] 9.4e-6 Pa
- [GV ITMX] 7.8e-6 Pa
- [GV ITMY] 6.9e-6 Pa
[Yamaguchi, Nakagaki]
We have changed the operation thresholds for the GV closure devices at the X and Y ends.
Together with yesterday's work, the set values for each device are as follows
- [ETMY] 9.6e-6 Pa
- [ITMY] 6.9e-6 Pa
- [BSY&BSX] 9.4e-6 Pa
- [ITMX] 7.8e-6 Pa
- [ETMX] 2.0e-5 Pa
The vacuum gauge used for the interlock system of GVexa fluctuated a lot.
The value sometimes reached 1*10^-5 Pa.
The sensor value of the trigger CC-10 near EXA fluctuates around (0.5~2) x 10^-5 Pa every several seconds. 2x10^-5 Pa was the threshold value for closing.
On the other hand, the CC-10 value at X-27 and at the EXC arma side never fluctuates. So this fluctuation is regarded as fake. Although Uchiyama-kun and Nakagaki-san replaced the electrical part of this CC-10 recently, this fluctuation did not stop. So we need to change its body itself.
The attached figure shows the value from the CC-10 at EXA in Light green. It obviously fluctuated a lot in the past several hours.
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I also confirmed that the indicator lamp at EXA GV was RED.
Kimura-san and YamaK-san will go to the KAGRA site, open GV, and set a higher value for the threshold tomorrow.
Kimura, K Yamamoto, Ushiba(remote), Uchiyama(remote)
We opened GVexa at 9:50.
Today's safety shift (Kimura-sama and Yamamoto-sama) visited the Xend to open GVexa. Kimura-sama checked the vacuum gauge's D-sub connector, but nothing was found. Since we could not recover the vacuum gauge's situation, we decided to deactivate the interlock system for GVexa.
Please be careful of the actual leak event which will be reported via e-mail because the IM temp reached around 140K.
Yasui, Sawada, Kimura(remote), Yamaguchi, Yoshimura, Uchiyama
We exchanged the vacuum gauge used for the GVexa interlock. However, the new vacuum gauge was broken.
We closed the GV between the beam duct and the flange on which the vacuum gauge was attached. Then, we vented the vacuum gauge and exchanged it for a new one.
After the exchange, we pomped down the vacuum gauge by the leak detector. Initially, the vacuum gauge looked healthy during the vacuum level of the Pirani gauge. However, at the point of changing to the cold cathode gauge, the vacuum gauge showed 9.9*10^5Pa. It was so strange value.
Next, We exchanged only the circuit box but the vacuum gauge showed still 9.9*10^5Pa.
Finally, we changed the power supply cable and the vacuum gauge showed the error code which says that the gauge is necessary to be exchanged.
It will be restored after recovering the vacuum gauge.
Notification for GV@BS, @ITMX, and @ITMY are still working well.
[Kimura(remote), SawadaH, Nakagaki, Yasui]
We replaced the vacuum gauge at GVexa, and it seems work healty.
1. Connected the new CC-10 to an independent pump unit and confirmed to reach 10^-5 Pa properly.
2. Nakagaki-san checked the power supply cable from interlock system to CC-10 and confirmed that it has no problems.
3. Replaced strange CC-10 to the healthy one(=step1).
4. Performed He leak check.
5. Another CC-10,had previously exhibited strange behavior, was connected to an independent pump unit and confirmed to reach 10^-5 Pa without any problems.
6. Connected the power cable from interlock(=step2) to this CC-10(=Step5) and confirmed that there are no problems.
7. Connected that power cable to the CC-10(=Step3).
8. Pumped down the vacuum gauge by an independent pump unit.
Nakagaki, Yasui
Sorry, the serial communication setting for the CC-10 was incorrect.
We changed the setting as follows:
parity bit 02 -> 00
Currently, the actual vacuum level can be checked via the network.
[Kimura and Yasui]
We changed and confirmed the operating threshold of the alarm contacts within CC-10s for ithe ineterlocks as follows;
GVbsx & GVbsy :8.0 x 10^-6 Pa
GVitmx: 5.9 x 10^-5 Pa
GVitmy: 5.9 x 10^-5 Pa
GVetmy: 5.9 x 10^-5 Pa
As reported K-log(32354), the alarm contacts are designed to operate when the threshold is exceeded.
The threshold of GVetmx will change in this afternoon.
[Kimura and Yasui]
We changed and confirmed the operating threshold of the alarm contacts within CC-10 for the ineterlock of GVetmx as follows;
GVetmx: 5.9 x 10^-5 Pa
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[Kimura and Yasui]
We changed and confirmed the operating threshold of the alarm contacts within CC-10 for the ineterlock of GVbsx and GVbsy as follows;
GVbsx & GVbsy: 1.0 x 10^-5 Pa