A CAL Tcam session was performed to obtain beam position information necessary for Pcal. The parameters have already been updated, and SDF has been accepted.

Operator: Shingo Hido, Kohei Mitsuhashi, Dan Chen

Update Time: 2026/03/18 07:41:38

This work is continued from klog36589

## GAS control modification

According to yesterday's results related to GAS, there seem to be gain peaking at 3-4 Hz. So I reduced {F0,F1,BF} gains to -6dB. After that I measured their OLTFs when SR2 is in the LOCK_ACQUISITION state. Fig.1,2,3 show the results. Unfortunately, OLTF could not be measured well maybe due to the coupling between GAS controls. Acoording to loop suppression (IN2/EXC), their controls seem to work well and the peaking around 3-4Hz becomes smaller. Fig.4 shows the error/feedback spectra. The peaking seems to be disappeared although each residual GAS motion seems to be not changed so much.

## IM DAMP roll off modification

I also modified the roll off filters for IM DAMP {L, P, R, Y}. As for T and V, elliptic filter was also not used in SR3. So I did not touch them in this time. (Maybe it is better to change)

I measured the OLTFs after the modification. Figure.5, 6, 7, and 8 show the OLTFs of IM DAMP {L,P,R,Y}. Also Fig. 9 and 10 show the error/feedback spectra. the feedback above 10 Hz was rolled off successfully.

[Kimura and Yasui]

 At around 10:00 a.m. on March 17, we stopped the vacuum pumping in the Q-mass piping, opened the cryostat-side GV, and connected the Q-mass.
The pressure inside the piping before opening the cryostat-side GV was 1.8×10⁻⁴ Pa, and after opening the GV, it was 4.4×10⁻⁵ Pa.
 We then installed an analysis unit on the Q-mass piping. The final pressure inside the piping was 3.5 × 10⁻⁵ Pa.
We then removed the vacuum pumping unit from the piping.

[Kimura and Yasui]

 On March 17, we completed maintenance work on the duct-shield cryo-coolers for IXC and IYC.
Maintenance work on the duct-shield cryo-coolers for EXC and EYC is also scheduled to be completed by the end of this week.
We are planning to restart the duct-shield cryo-coolers starting March 23, which will also serve as a test run.

Workers: Kohei Mitsuhashi, Dan Chen

We performed monthly Pcal-Y calibration on 2026/03/17.

After the calibration, we updated EPICS parameters related to the Pcal-Y system. No issues were found.

A CAL Tcam session was performed to obtain beam position information necessary for Pcal. The parameters have already been updated, and SDF has been accepted.

Operator: Kohei Mitsuhashi, Dan Chen

Update Time: 2026/03/17 15:31:24

I offloaded the F2 and BF GAS filters with the FRs.

[Washimi, Takahashi]

We replaced the broken signal generator (SG) NF1956 with the embedded SG card for the LVDT driver (S1807787) in TMSX. We opened the driver chassis and inserted the SG card. The output of the SG card was connected to "REF IN" port on the front panel. The signal was set to 10kHz in frequency and 7Vp-p in amplitude.

The new Pastavi server was purchased with the SEO budget and delivered to the KAGRA site. I performed the initial setup on the server and copied the data viewer system. After completing the preparation at the KAGRA site, I sent it to Kashiwa last Friday. I will replace the server in Kamioka this Thursday. 
Please note that it may take some time to recover the noise budget mode. I expect it to be restored within a few days.

Note

• Because the OS version jumped significantly from 9 to 12, many modifications to the settings were necessary.
• The cgi package has been deprecated from Python 3.13. Although it is possible to use legacy-cgi, its behavior was slightly different from what I expected. Therefore, I decided to use Python 3.12. In the future, it may be necessary to redevelop Pastavi using another framework or tool.
• Installation of the frameL was not as straightforward as in the previous environment  (actually I just wanted to use the FrChannels command). The procedure for installing lal (or framel) using apt is described on the following pages: [wiki] [IGWN debian repo]

ITMX has successfully reached the LOCK_ACQUISITION state.
We will leave it in this state for a while to verify that no issues arise with the new V2 I/O chassis.

I offloaded the IP H2 with the FR for recovery from the saturation. The guardian state could be switched from READY to ISOLATED.

[Takahashi, Washimi, Hirata]

We replaced the window mirror (SRM-W) with the 70% mirror (SRM-M). This is a demonstration for training in replacement. At the beginning, we confirmed the mirror's wedge direction: the X- side (Picture 1). We removed the black cylinder from the rear side and removed the mirror holder (Picture 2) by pushing with a Teflon bar from the rear side (Picture 3). We attached the assembled 70% mirror to the test mass (Picture 4), confirming the wedge direction (Picture 5).

We checked the extracted window mirror. The mirror thickness was 9.6mm at the wedge marker. Two 0.5mm shims were used as the spacer for the flange.

## Abstract

In order to unifiy the design philosophy of Type B local controll filter, I began to modify the control filter in the SR2 tower part (IP_IDAMP_Y, {F0,F1,BF}_DAMP), especially their roll off filters so that the same filters as SR3 are used in SR2.

Feedback spectra above 10 Hz seem to be reduced thanks to this modification. However, there seems to be gain peaking at 3-4 Hz in GAS signals. so we need to adjust them.

## What we did

In order to unifiy the design philosophy of Type B local controll filter, I began to modify the control filter in the SR2 tower part (IP_IDAMP_Y, {F0,F1,BF}_DAMP) so that the same filters as SR3 are used in SR2.

Basically,  the difference between SR2 and SR3 controll fitlers was the roll-off filters. SR3 usually used the 4th order elliptical lowpass filter. On the other hand, SR2 used 2nd or 3rd order pole. Therefore, the gain of the SR2 filter above 100 Hz is typically more than 20dB larger than the one of SR3. This indicates the SR2 filter transmits the 20dB larger sensor noise above 100 Hz to the suspension. So, I tried to impliment the same roll off fiter to SR2 control.

Fig. 1 shows the example of the modification for SR2_IP_IDAMP_Y. Fig.2 shows the medm screen of SR2_IP_IDAMP at that moment. I modified the roll off filter for GASs in the same manner.

After the implementation, I confirmed that SR2 could be reached LOCK_ACQUISITION state. Then, I measured the spectra of error/feedback signals of their controls in the LOCK_ACQUISITION state. Fig.3 and 4 shows the results of IP and GAS, respectively. Red curves in figures are current SR2 error/feedback signal spectra and magenta curves are the spectra before the modification. Blues(and Cyans) are the spectra of SR3 as references. Above 10 Hz, the feedback signals' spectra were reduced successfully. On the other hand, there seems to be gain peaking at 3-4 Hz in GAS signals. So we need to fix them.

## Next

• IM_DAMP_{L,T,V,R,P,Y}

ICX6610-24P Switch>show ip
     Switch IP address: None
           Subnet mask: None
Default router address: None
   TFTP server address: None
Configuration filename: None
        Image filename: None
                IP MTU: 9216

ICX6610-24P Switch>enable
ICX6610-24P Switch#configure terminal
ICX6610-24P Switch(config)#vlan 1
ICX6610-24P Switch(config-vlan-1)#ip address  
ICX6610-24P Switch(config-vlan-1)#exit
ICX6610-24P Switch(config)#write memory
Flash Memory Write (8192 bytes per dot).
Flash to Flash Done.

telnet@ICX6610-24P Switch>show media
Port 1/3/1:  Type : 10GE LR 10km (SFP +)
telnet@ICX6610-24P Switch>show interface brief
Port    Link    State   Dupl Speed Trunk Tag Pvid Pri MAC             Name
1/3/1   Up      Forward Full 1G    None  No  1    0   cc4e.24f9.762b     

telnet@ICX6610-24P Switch>show license
License record empty

telnet@ICX6610-24P Switch>enable
telnet@ICX6610-24P Switch#configure terminal
telnet@ICX6610-24P Switch(config)#interface ethernet 1/1/24
telnet@ICX6610-24P Switch(config-if-e1000-1/1/24)# inline power

When I tried to migrate a copy process of Weather Station Web pages on k1script, I found k1script couldn't access Weather Station@Atotsu.
It was since Feb. 9th according to the last update on the Web page.
Weather Station@Atotsu cannot be launched due to CMOS error now.
A replacement of a CMOS battery (or PC itself in the worst case) seems to be required to recover it.

-----
A copy process of Weather Station Web pages was migrated from the old k1script1 to the new k1script0. This process for Weather Station at Mozumi works fine. On the other hand, it for at Atotsu couldn't access Weather Station PC. Because the old process on k1script1 was also failed, I concluded that it was a problem on the Weather Station PC not on the k1script.

Any remote connections wasn't available, so I checked a situation by plugging a display to the Weather Station PC at Atotsu and found that gathering hardware information before booting OS up failed due to the CMOS trouble as shown in Fig.1. This message is also shown when a CMOS battery (often use CR2032 on common server) becomes empty. Of course, there is some possibility about a malfunction of a motherboard. Anyway what we can try at first is opening PC chassis, and then replacing the CMOS battery if there is no obvious malfunction on the mother board.