Here are the mass properties for the only the test mass assembly (optic, 3" ring, and wire block). (Updated with g*mm^2)

The current vertical distance between the CoM and the wire clamping point on the 3" Ring assembly is 0.33mm. That is the CoM is .33 mm below the clamping point of the wire. I took the clamping point to be the top edge of the wire clamp piece. see the below attachments.

I am now modifying the dumbell mechanism at the bottom of the ring to move the CoM to the target distance of 1.1mm.

After changing the material of the Balance Mass from 6061 Al to 304 Steel, and changing the thickness to 0.21" from 0.25". The CoM is now 1.11mm below the clamping point.

Koji expected a mass change of ~ 4g to move the mass to 1.1mm. The 6061 mass weighed ~1.31g and the 304 mass weighs 4.1g.

A potential issue with this is the screw used the adjust the position of these balance masses, threads through both the aluminum ring and this now 304 steel mass. A non silver plated screw could cold weld at the mass, but a silver plated screw will gall in the aluminum threads.

8 of the 2"->3" adapter rings (D2100377) arrived from RDL yesterday. I have not tested the threads but dimensional inspection on SN008 cleared. Parts look very good. The rest of the parts should be shipping out in the next week.

The right N2 tank had a bad/loose valve and did not fully open. This morning the left tank was just about empty and the right tank showed 2000+ psi on the gauge. Once the changeover happened the copper line emptied but the valve to the N2 tank was not fully opened. I noticed the gauges were both reading zero at ~1pm just before the meeting. I swapped the left tank, but not in time. The vacuum interlocks tripped at 1:04 pm today when the N2 pressure to the vacuum valves fell below 65psi. After the meeting, Chub tightened the valve, fully opened it and refilled the lines. I will monitor the tank pressures today and make sure all is ok.

There used to be a mailer that was sent out when the sum pressure of the two tanks fell <600 psi, telling you to swap tanks. Does this no longer exist?

Yehonathan noticed today that the silver plated hardware on the assembled SOS towers had some pretty severe discoloration on it. See attached picture.

These were all brand new screws from UC components, and have been sitting on the flow bench for a couple months now. I believe this is just oxidation and is not an issue, I spoke to Calum as well and showed him the attached picture and he agreed it was likely oxidation and should not be a problem once installed.

He did mention if there is any concern from anyone, we could take an FTIR sample and send it to JPL for analysis, but this would cost a few hundred dollars.

I don't believe this to be an issue, but it is odd that they oxidized so quickly. Just wanted to relay this to everyone else to see if there was any concern.

The remaining machined parts for the SOS adapter ring have arrived. I will inspect these today and get them ready for C&B.

I had 8 standoffs made at the Caltech chemistry machine shop to be used as spacers for the side magnets on the 3" Ring assembly. This is to create enough clearance between the magnet and the cap screws directly above on the wire clamp.

These are 0.075" diameter by .10" length. Putting them through clean and bake now.

After an overnight pumpdown/RGA warm up, I took a 100 amu scan of the RGA volume and subsequent pumping line. Attached is a screenshot along with the .txt file. Given the high argon peak (40) and the N2/O2 ratio, it looks like there is a decent sized air leak somehwere in the volume.

Are we interested in the hydrocarbon leak rates of this volume? That will require another scan with one of the calibrated leaks opened.

Edit: Added a Torr v AMU plot to see the partial pressures

Jordan, Chub

We installed the 4x DB25 feedthru flange on the North-West port of ITMX chamber this afternoon. It is ready to go.

Jordan, Chub

Today, Chub and I removed TP1 and the failed manual gate valve off of the pumping spool.

First, P2 needed to be vented in order to remove TP1. TP1 has a purge valve on the side of the pump which we slowly opened bringing the P2 volume up to atmosphere. Although, this was not vented using the dry air/N2, using this purge valve eliminated the need to vent the RGA volume.

Then we disconnected TP1 foreline, removed TP1+8" flange reducer, then the gate valve. All of the removed hardware looked good, so no need to replace bolts/nuts, only needs new gaskets. TP1 and the failed valve are sitting on a cart wrapped in foil next to the pumping station.

Jordan, Chub

Chub and I installed the new manual gate valve (Nor-Cal GVM-6002-CF-K79) and reinstalled TP1. The new gate valave was placed with the sealing side towards the main 40m volume, then TP1 was installed on top and the foreline reattched to TP1.

This valve has a hard stop in the actuator to prevent over torquing.

Jordan, Chub, Paco

Chub and I went into the lab this morning to leak check the new gate valve after pumping over the weekend. This would be done through the RGA and spraying helium around the newly installed flanges. The RGA is set to monitor the partial pressure of helium versus time and we visually watch for any spikes in pressure to indicate an air leak.

So, I mistakenly thought the gate valve was opened and both sides were being pumped on, this was not the case. The vavle was closed so there was a pressure differential whenI turned the handle it tripped the interlocks and closed V4. I closed VM3 to the RGA volume to prevent the filament from being damaged.

Then the medm screen for the vac controls started flashing rapidly, I closed the window and reopened the controls to find all the panels were white, but we could still see the read only vac screen. So Paco restarted c1vac and the controls were restored. V7 closed, but was then reopened.

We now need to restart pumping with the odd pressure differentials between V4 and VM3.

Plan

- TP2 turned off along with the AUX pump

- VM3 opened to vent RGA volume (RGA turned off, filament cooled)

- Open the manual vent screw on TP1 to bring the RGA+TP1 volume back to atmosphere, now no pressure diff. on V4

- Open V4, restart AUX pump to rough out the volume

- Connect RP1/3 line to the pump scroll, turn on RP1/3 RGA+TP1 volume went to mtorr

- Slowly open the manual gate valve

- Connect AUX pump to TP2 and rough out

- Restart TP2, once at speed open V4, close V6 and turn off RP1/3

Now we are pumping on the RGA/TP1 volume with TP2, leak check attempt #2 will happen tomorrow morning

This morning Chub and I leak checked the manual gate valve with the RGA and helium. There was no change in the helium partial pressure while spraying helium around the flanges, all looks good.

I also took a 100 AMU analog scan, after the filament had warmed up overnight and the plot was quite noisy even with the lowest scan speed. I recommend this unit go back to SRS for a filament replacement/recalibration. I am worried yesterday's "vent" of the RGA volume may have burned the filament. See the comparison of yesterday's analog scan to today's below.

Today, Tega and I would like to vent the pump spool an dinstall the new FRG-400 Agilent Pressure Gauges (per elog 15703). The attached picture shows the volume needed to be vented highlighted in red, and the gauges that need to be replaced/removed (purple dot next to the name).

The vent plan is as follows:

Open RV2

Open VM3

Open V7

Open V4

Shut down TP2

Install new gauges

Will add to post with updates post vent.

Prior to venting the RGA volume on Tuesday (4/12/2022) I took an RGA scan of the volume to be vented (RGA+TP1 volume+Manual Gate Valve) to see if there was a difference after replacing the manual gate valve. Attached is the plot from 4/12/22, and an overlay plot to complare 4/12/22 to 12/10/2021, when the same volume was scanned with the old (defective) manual gate valve.

There is a significant drop in the ratio O2 compared the the nitrogen peak and reduced Argon (AMU 40) which indicates there is no longer a large air leak.

12/10/21 N2/O2 ratio ~ 4 (Air 78%N2 / 21%O2)

4/12/22 N2/O2 ratio ~ 10      

There is one significant (above noise level) peak above AMU 46, which is at AMU 58. This could possibly be acetone (AMU 43 and 58) but overall the new RGA Volume scans look significantly better after the manual gate valve replacement. Well done!

Jordan, JC

While the pumpspool is vented, I thought it would be a convenient time to change out the tip seal on the TP3 forepump. This one had not been changed since 2018, so as preventative maintence I had JC remove the pump and begin cleaning/installing the new tip seal.

Unfortunately the tip seal broke, but I have ordered another. We should have this pump ready to go late next week. If one is needed sooner, there is a spare IDP 7 pump we can install as the TP3 forepump.

[JC, Jordan]

Jordan recieved the new tip seal Friday afternoon and I continued the replacement process in the morning. Finishing up, we proceeded to test the pump in the Clean and Bake room. The pump's pressure lowered to 110 mTorr, and we continue pumping so the seal can recieve a good fitting.

Update: We have confirmed the pump is working great and have reinstalled this back into the vacuum system.                                                                                                                   Note: The same O-Rings were used.

The NDS2 server on megatron was unresponsive for what i think was the last couple of days.

The NDS the log file (~nds2mgr/logs/nds2-201407151045.log) started reporting "Stage: parser output queue is full." at 2014.7.24 14:47:54 also there are 16 connections still not closed with LindmeierLaptop.cacr.caltech.edu (131.215.146.102) with 15 of them in CLOSE_WAIT. 

To identify these zombie sockets we use "netstat -an | grep 31200"

The server was in a condition that /etc/init.d/nds2 stop didn't work and the process had to be manually kill -9'ed and then about 3 or 4 minutes later the zombie sockets were gone at /etc/init.d/nds2 start was used to restart the server.

The LindemejerLaptop was using pynds to get a bunch of channels at once to test drive a streaming visualization code for glitches.  It's unclear whether this bumped into a server limitation.  We have seen similar states in ldvw that seem to be the result of errors which result in client-server connections not being closed properly, leaving data in an output buffer causing Linux to wait for the other side to empty the buffer.

Josh Smith, Fabian Magana-Sandoval, Jackie Lee (Fullerton)

Thanks to Jamie and Jenne for the tour and the input on the pages.

We had a look at the GEO summary pages and thought about how best to make a 40m summary page that would eventually become and aligo summary page. Here's a rough plan:

- First we'll check that we can access the 40m NDS2 server to get data from the 40m lab in Fullerton.

- We'll make a first draft of a 40m summary page in python, using pynds, and base the layout on the current geo summary pages.

- When this takes shape we'll iterate with Jamie, Jenne, Rana to get more ideas for measurements, layout.

Other suggestions: Jenne is working on an automated noisebudget and suggests having a placeholder for it on the page. We can also incorporate some of the features of Aidan's 40m overview medm screen that's in progress, possibly with different plots corresponding to different parts of the drawing, etc. Jenne also will email us the link of once per hour medm screenshots.

I attach the transfar function of the current shunt.
There is a little gap at 10 Hz for phase, but it is a ploblem of measurement and not real one.
 

I attache the transfar function of ISS servo.

The 4th stage and variable gain amplifier has alomost same transfar function, so their lines pile up.

I measured the output noise of eache stage of ISS servo, and calcurated the noise ratio between input and 
output of each stage.
Generaly, each noise ratio corresponds to their transfar function. This means servo filter works well, not 
adding extra noise.

I attache example of them.
For 2nd stage, the noise ratio is smaller than transfar function with a few factor. This is because the 
input noise is coverd by analyser's noise and ratio between output and input looks small.
This means the input noise of 2nd stage was enough small and all stage before 2nd stage work well

I added a PA current limiter.
It is only a voltage devider (composed with 3.09k and 1.02k resiste) between DAC and PA current adjustment input.
The output range of DAC is +/- 10[V] and  the conversion factor of PA current adjustment is 0.84[A/V] (measured value), so the PA current adjustment is limited +/- 2.1[A] ( 10[V]*1.02k/(1.02k+3.09k)*0.84[A/V] ).

Actually, the manual of the PA tells that the conversion factor is 0.25[A/V].
There is 3 possibility.
1) There are some mistakes in channels of digital system.
2) The PA manual is wrong.
  2-1) The conversion factor of current adjustment is wrong.
  2-2) The conversion factor of current monitor is wrong.
I measured the signal of current adjustment and current monitor directly, and confirm that they are consistent to the value monitord from MEDM.
Hence the PA manual must be wrong, but I don't know which factor is wrong (or both?).
If the suspect 2-2) is guilty, it means we adjust PA current with very small range.
This is a completly safety way, but a wast of resource.

Now, the slider to control current adjustment indicate the output of DAC.
I will improve this to indicate  current adjustment input, but it takes some time for me to learn about EPICS.

I found a strange jump of value in my data taken with tdsdata.
I couldn't find same jump in a playback of DataViewer, so I think this is a problem of tdsdata.
Be careful when you use tdsdata!

The attached file is an example of jumped data.
I try to get data with allegra and op440m, and both has same kind of jump.
(A downsampling or interpolation may be wrong.)

Rana said there is a fixed version of tdsdata in some PC, but 64bit linux may not have.
I try it tomorrow.

I found that tdsdata doesn't work.

When I star tdsdata, he takes a few ~ 10 seconds of data, and he dies with a message "Segmentation fault".
I tried to get data for some times and some channels, and this problem was observed everytime.
I also tried tdsdata on allegra, op440m and mafalda, and it didn't work on all of them.

Yesterday, I got a new version of tdsdata (which modified the problem of Message ID: 1328) and tried to build 
thme on my directory (/cvs/cds/caltech/users/kakeru.....)
This may have some relation to this problem.

I tested new tdsdata and found it was working well.

I excited C1:SUS-ITMY_SUSPIT_EXC with tdssine, and get data from C1:LSC-TRY_OUT (testpoint) and C1:SUS- ITMY_OPLEV_PERROR (recorded point) with new and old tdsdata.

With old tdsdata (/cvs/cds/caltech/apps/linux/tds/bin/tdsdata), I found some jumps of datapoint, which is a same problem with before (Attachment 1).

With new tdsdata (/cvs/cds/caltech/apps/linux/tds_090304/bin/tdsdata), there looks to be no jumps (Attachment 2; taken about 10 minutes after Attachment 1).

The problem of old tdsdata looks to be remaining even for recordedpoints.

You should use /cvs/cds/caltech/apps/linux/tds_090304/bin/tdsdata.

ITMX Pitch: 142   microrad/counts
ITMX Yaw:   145   microrad/counts
ITMY Pitch: 257   microrad/counts
ITMY Yaw:   206   microrad/counts

ETMX Pitch: 318   microrad/counts
ETMX Yaw:   291   microrad/counts
ETMY Pitch: 309   microrad/counts
ETMY Yaw:   299   microrad/counts

BS Pitch:    70.9 microrad/counts
BS Yaw:      96.3 microrad/counts

PRM Pitch:   78.5 microrad/counts
PRM Yaw:     79.9 microrad/counts

SRM Pitch:  191   microrad/counts
SRM Yaw:    146   microrad/counts

Kakeru and Kiwamu

We placed a QPD on the PSL bench for PSL angle monitor.

 As we mentioned before, old QPD which used to be placed is broken.

 And we put broken QPD into the "photodiodes" box under the soldering table.

This morning, MC alignment was gone and MC wasn't lock.

We checked old value of pitch, yaw, and position offset of each MC mirror, and found they were jumped.

We don't know the reason of this jump, but we restore each offset value and MC backed to lock.

We found c1lsc, c1iscex, c1iscey, c1susvme, c1asc and c1sosvme are dead.
We  turned off all watchdogs and turned off all lock of suspensions.
Then, I tried to reboot these machines from terminal, but I couldn't login to all of these machines.

So, we turned off and on key switches of these machines physically, and login to them to run startup scripts.

Then we turned on all watchdogs and restored all IFO.

Now they look like they are working fine.
 

We found that one OP-amp used in ISS servo oscillated in 10 MHz, 100mV.

Moreover, we found another OP-amp had big noise.

We guess that these oscilation or noise cause saturation in high frequency, and they effect to lower frequency to cause 

 Attached files are open loop transfar function of ISS.

The blue points are open loop TF, and the green line is product of TF of ISS servo filter and TF of current shunt TF of servo filter.

This two must be same in principle, but They have difference f<2Hz and f>5kHz.

We centerd the input of WFS QPD.

We found that the MC REFL image was no longer round and that the MCWFS DC quadrant spots were mostly
in one quadrant. So we re-centered the MCWFS beams in the following way:

1) We unlocked the MZ and adjusted the PZT voltage to keep the beam on the WFS from saturating.
2) Re-aligned the black hole beam dump to center its beam in its aperture.
3) centered the beam on the MCWFS optics and MCWFS QPD displays.
4) Relocked MC.

Below is the image of the IOO Strip tool. You can see that the MC REFL DC is now more flat. The
MC pointing has also been changed (see the MC TRANS HOR & VERT channels). The MC transmitted
light is also now more stable and higher.

We tried to center the QPD, and we found that there were a few hundred mV of dark offset for each 
quadrant of QPD. We adjusted them with this scripts:
/cvs/cds/caltech/scripts/MC/WFS/McWFS_dc_offsets

We confirmed that new tds(/cvs/cds/caltech/apps/linux/tds_090304/) works well on linux 64, and replaced it to /cvs/cds/caltech/apps/linux/tds/

The old /cvs/cds/caltech/apps/linux/tds is put in /cvs/cds/caltech/apps/linux/tds.bak

Yoichi and me found that the transfar function of the current shunt changed with the current of PA.
We changed PA current and fixed the unstability of ISS.
Now, laser power is stabilized finely, with band of about 1 Hz.
Yoich will post the stabilized noise spectrum.

There looks to be some non-linear relation between PA current and  the TF of current shunt.
It had changed from the TF which we measured yesterday, so it might change again.

I try to write scripts to sweep PA current and measure the laser power and its rms automatically.
It will be apply for auto-adjustment of PA current.

Attached files are the transfar function of the current shunt with changing PA.
They have difference in lower frequency.

We found the MC reflection was distorted . And WFC beam went to upward of QPD

We recentered WFC beam and these problems were fixed

 Kate & Jenne

About 2:30 this afternoon, we briefly powered off the Guralp (C1:PEM-SEIS_GUR1_{X,Y,Z}) in order to better align it with the other seismometers along its marked N/S direction. It had been visibly off by a few degrees.