 Wed Apr 13 16:23:54 2022, Ian MacMillan, Update, General, Smell in 40m
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[Ian, Paco, JC]
There is a strange smell in the 40m. It smells like a chemically burning smell maybe like a shorted component. I went around with the IR
camera to see if anything was unusually hot but I didn't see anything. The smell seems to be concentrated at the vertex and down the y-arm |
 Wed Apr 13 18:55:54 2022, Koji, Update, Cameras, Camera Battery Test
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I believe that the Nikon has an exposure problem and that's why we bought the Canon.
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Thu Apr 14 09:04:30 2022, Jordan, Update, VAC, RGA Volume RGA Scans 
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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. |
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Fri Apr 15 11:59:16 2022, Yehonathan, Update, IOO, IMC completely misaligned
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Came this morning, opened the PSL and there was not even a beam on the MC REFL.
Looking at the big monitor it seems like the WFS signals went through the roof during the "auto-alignment" night session.
I restored the MC alignment from before the misalignment happen and wait for the SUS to damp. Once the RMS values went below 200 I enabled the |
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Mon Apr 18 15:17:31 2022, Jancarlo, Update, General, Tool box and Work Station Organization
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I cleaned up around the 40 m lab. All the Laser Safety Glasses have been picked up and placed on the rack at the entrance.
Some miscellaneous BNC Connector cables have been arranged and organized along the wall parallel to the Y-Tunnel.
Nitrogen tanks have been swapped out. Current tank is at 1200 psi and the other is at 1850 psi. |
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Mon Apr 18 16:09:07 2022, Yehonathan, Update, BHD, BHD Readout simulation
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I'm planning on simulating the BHD readout noise in a manner very similar to the ALS noise model using Simulink. I've made a sketch of the model
for the longitudinal DOFs (attached). A model for ASC will be similar but with more measurement devices (OpLevs, QPDs, WFSs).
I'm not pretending to simulate everything in this diagram on the first go, it is just a sketch of the big picture. |
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Mon Apr 18 23:22:39 2022, Koji, Update, General, Tool box and Work Station Organization
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| Whoa! Thanks! |
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Tue Apr 19 18:10:10 2022, Paco, Update, BHD, Part V of BHR upgrade - POX11 path, LO path, and ITMX Oplev
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[Yuta, Paco]
We set up POX11 beam path from ITMX chamber to the ITMX in-air table. To do this, we first identified the POX reflection on the ITMX chamber,
and then steered the POXM1 (in the BSC) by hand until we cleared the viewport. We also checked that the POX beam is centered on POXM1. |
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Wed Apr 20 08:20:22 2022, Paco, Update, BHD, Part V of BHR upgrade - PR2 weirdness
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Yesterday, I tried tuning the PR2 damping gains by increasing the gain until the damping gave the ~5 oscillations (by watching the damped motion using
StripTool, and keeping an eye on the PD var). I noticed that often when I changed the gain, some OSEM sensors shifted (gained an offset!!) and the PD var
values changed, typically increasing at higher damping gains. I reverted the changes until the PD var looked "normal" again (~ 2 mV) but it is |
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Wed Apr 20 14:56:06 2022, Tommy, Update, Electronics, RFSoC 2x2 board -- setup for remote work & BALUN saga
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Here are a few options for replacement BALUNs from Mini Circuits and specs:
Current. TCM1-83X+, 10-8000 MHz, 50 Ohms, Impedance Ratio 1, Configuration K
1. Z7550-..., DC-2500 MHz (some DC-2300), 50/75 Ohms, Impedance Ratio 1.5, Configuration Q. There are various types of the Z7550 which have different |
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Wed Apr 20 16:11:08 2022, Koji, Update, SUS, Outpur resistors updated for LO1 coil drivers / for SR2, LO2, AS1, and AS4 in progress 6x
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[JC Koji]
To give more alignment ranges for the SUS alignment, we started updating the output resistors of the BHD SUS coil drivers.
As Paco has already started working on LO1 alignment, we urgently updated the output Rs for LO1 coil drivers. |
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Wed Apr 20 18:50:03 2022, Koji, Update, BHD, Part V of BHR upgrade - PR2 weirdness
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It seemed that it comes from the servo oscillation. This does not happen when the output limitters were set to be 100-ish. But even so the gains looked
quite low.
I turned on the Cheby rool-offs for all the DOFs, and this allowed me to increase the damping gain A LOT. |
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Thu Apr 21 10:35:23 2022, Koji, Update, CDS, DAQ seemed down
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Yesterday, when I worked on the damping servo, I found that any of the daqvtools (ndscope, dtt, dataviewer,...) is not available. We may need to
restart the fb and rt machines. |
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Thu Apr 21 11:31:35 2022, JC, Update, VAC, Gauges P3/P4
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[Jordan, JC]
It was brought to attention during yesterday's meeting that the pressures in the vacuum system were not equivalent althought the valve were
open. So this morning, Jordan and I reviewed the pressure gauges P3 and P4. We attempted to recalibrate, but the gauges were unresponsive. Following this, |
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Thu Apr 21 15:22:44 2022, Koji, Update, SUS, Outpur resistors updates for SR2, LO2, AS1, and AS4 done
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[JC Koji]
Quick report: JC has done all the mods for the coil driver circuit in the morning and we worked on the reinstallation of them in the afternoon.
I'll check the damping loops / sus servo settings. JC is going to make an ELOG entry and DCC updates for more precise record of the mods. |
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Thu Apr 21 16:36:56 2022, Tega, Update, VAC, cleanup work for vacuum git repo
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git repo - https://git.ligo.org/40m/vac
Finally incorporated the FRGs into the main modbusIOC service and everything seems to be working fine. I have also removed the old sensors (CC1,CC2,CC3,CC4,PTP1,IG1)
from the serial client list and their corresponding EPICS channels. Furthermore, the interlock service python script has been updated so that all occurrence |
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Thu Apr 21 16:49:01 2022, Paco, Update, BHD, Part V of BHR upgrade - BS Oplev + LO1 offset
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[Paco, JC, Yuta]
We aligned the BS oplev using the new BSOL mirror pair. The main change is now the AOI of the oplev on the BS is quite normal. The output beam
in the in-air table was quite large (diverging?) so we had to place a short FL lens in front of the QPD. |
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Thu Apr 21 18:18:42 2022, yehonathan, Update, BHD, POX Alignment
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{Yehonathan, Paco}
BS, ITMX and ETMX were aligned to get flashing in the X arm.
I aligned the POX beam on the ITMX table using a mixture of the old POP and POX optics. The beam was stirred to the POX11 RFPD. We measure the |
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Thu Apr 21 18:42:47 2022, Tega, Update, BHD, Part V of BHR upgrade - Align LO and AS beams to BHD BS
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[Tega, Yuta, Paco]
We tried aligning the LO and AS beams on to the BHD beamsplitter. During the alignment process, we noticed that the damping loop for AS1 was
not working. Paco drew our attention to the fact that the UR OSEM signal was alway close to zero, so we checked to ensure that the magnet was still within |
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Thu Apr 21 20:33:31 2022, Koji, Update, BHD, AS1 UR OSEM problem localized in the chamber
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Tega and Paco reported that the UR OSEM of AS1 lost the response.
- I have checked the LED MON (left) of the satellite amp for AS1. CH1/2/3 had 5V -> This indicates that the OSEM LEDs are (most likely) functioning.
- Then I went to the ITMY flange and connected the OSEM emulator instead of the Dsub25 cable. The attachment shows that the UR OSEM LED/PD worked |
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Fri Apr 22 07:01:58 2022, Jc, Update, Coil Drivers, Adding Resistors and Reinstalling 8x
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[Koji, JC]
Coil Drivers LO2, SR2, AS4, and AS1 have been updated a reinstalled into the system.
LO2 Coil Driver 1 (UL/LL/UR)now has R=100 // 1.2k ~ 92Ohm for CH1/2/3 Unit: S2100008 |
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Fri Apr 22 12:03:09 2022, Tega, Update, BHD, AS1 UR OSEM problem localized in the chamber
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[JC, Tega, Ian, Paco]
We found that the UR cable was clamped to the table by one of the ITMY OPLEV steering mirror mounts that was recently installed. After freeing
the cable, the UR signal is now active again. |
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Fri Apr 22 12:09:51 2022, Anchal, Update, Coil Drivers, Please update DCC pages
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Nice. Please put this information on the DCC pages of the coil driver units. You'll find links to all the units in this document tree LIGO-E2100447.
For each page, click on "Change Metadata" from the left panel and add the change made to the resistor (including the resistor name on PCB, previous
and new value), and add a link to your previous elog post which has more details like photos, to "Notes and Changes", and upload an updated version |
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Fri Apr 22 12:15:08 2022, Anchal, Update, BHD, Cable post installation
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If someone gets time, let's put in all the cable posts and clean up our cable routing on the tables.
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Fri Apr 22 14:14:33 2022, Jordan, Update, VAC, TP3 Forepump tip seal replacement
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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. |
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Sun Apr 24 13:17:08 2022, Tommy, Update, Electronics, New RFSoC2x2 Overlay
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We recieved an overlay from Chris Stoughton which he used for a ZCU11 board. The overlay is supposed to be compatible with the RFSoC 2x2 and help enable
the Multi-Tile Synchronization (MTS) we need. He also provides a .py with the necessary low level connection to the board and its memory along with a few
sample notebooks. |
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Mon Apr 25 14:19:51 2022, JC, Update, General, Nitrogen Tank
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Coming in this morning, I checked on the Nitrogen tanks to check the level. One of the tanks were empty, so I went ahead and swapped it out. One tank
is at 946 PSI, the other is at 2573 PSI. I checked for leaks and found none. |
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Mon Apr 25 14:49:02 2022, Koji, Update, General, Nitrogen Tank
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For your (and mine) info:
N2 pressure can be monitored on the 40m summary page: https://nodus.ligo.caltech.edu:30889/detcharsummary/day/20220425/vacuum/
(you need to hit "today" to go to the current status) |
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Mon Apr 25 16:57:57 2022, Anchal, Update, BHD, Cable post installation
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[Anchal, Tega, JC]
We installed cable posts in ITMY, BS, and ITMX chambers for all the new suspensions. Now, there is no point where the OSEM connections are hanging
freely. |
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Mon Apr 25 17:24:06 2022, Anchal, Update, CDS, DAQ still down
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I investigated this issue today. At first, it seemed that only new suspension testpoints are inaccessible. I was able to use diaggui for a measurement
on MC2. The DAQ network cable between 1X4 and 1Y1 was tied and is very taught now (we should relieve this as soon as possible, best solution is to lay
down a longer cable over the bridge). My hypothesis is that the DAQ network might have broken while tying this cable and it probably did not come back |
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Mon Apr 25 18:00:03 2022, Ian MacMillan, Update, Upgrade, Cable supports update
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I have designed new cable supports for the new ribbon cables running up the side of the tables in the vacuum chambers.
The clamps that I have designed (shown in basic sketch attachment 1) will secure the cable at each of the currently used cable supports.
The support consists of a backplate and a frontplate. The backplate is secured to the leg of the table using a threaded screw. The frontplate |
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Tue Apr 26 16:23:22 2022, Tommy, Update, Electronics, RFSoC2x2 MTS
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We connected a 8 MHz signal generator to the device in order to sync up the ADCs and DACs and hopefully get phase data.
Some things to note:
RF Manual (143)- Need to use XRFDC SYSREF for update event
RF Manual (171)- Synchronization steps require us to first enable |
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Wed Apr 27 10:05:55 2022, JC, Update, Coil Drivers, Coil Drivers Update
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18 (9 pairs) Coil Drivers have been modified. Namely ETMX/ITMX/ITMY/BS/PRM/SRM/MC1/MC2/MC3.
ETMX Coil Driver 1 (UL/LL/UR)now has R=100 // 1.2k ~ 92Ohm for CH1/2/3 S2100624 |
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Thu Apr 28 09:12:18 2022, Anchal, Update, BHD, Restoring arm alignment
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This would be a daily first task in the morning. We'll need to check the status of arm alignment and optimize it back to maximum every morning for
the rest of the day's work.
Today, when I came, on openin gthe PSL shutter, IMC was aligned good, both arms were flashing but YARM maximum transmission count was around |
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Thu Apr 28 17:45:53 2022, Anchal, Update, BHD, POX Beam issues
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[Anchal, Paco]
We investigated the low power issue with POX11 photodiode.
We used a power meter to confirm that above 12 uW of power is reaching the ITMX oplev table.
But the power reaching the photodiode |
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Thu Apr 28 18:07:04 2022, Anchal, Update, BHD, Restoring arm alignment at EOD
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Restored arm algiment to get 0.8 max flashing on YARM and 1 max flashing on XARM. I had to move input alignment using TT2-PR3 pair and realign YARM cavity
axis using ITMY-ETMY pair.
I would like to advertise this useful tool that I've been |
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Fri Apr 29 08:34:40 2022, JC, Update, VAC, RGA Pump Down
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Jordan and I, in order to start pumpig down the RGA Volume, we began by opening V7 and VM. Afterwards, we started RP1 and RP3. After this, the pressure
in the line between RP1, RP3, and V6 dropped to 3.4 mTorr. Next, we tried to open V6, although an error message popped up. We haven't been able
to erase it since. But we were able to turn on TP2 with V4 closed. The pressure in that line is reporting 1.4 mTorr. |
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Sat Apr 30 13:29:33 2022, Paco, Update, BHD, POX Beam issues --- fixed, ASL alignment on vertex chamber
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[Paco, Anchal, Yuta]
We opened the BSC and ITMX chamber in the morning (Friday) to investigate POX11 beam clipping. We immediately found that the POX11 beam was clipping
by the recently installed cable posts, so luckily no major realingment had to be done after reinstalling the cable post in a better location. |
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Mon May 2 10:00:34 2022, Jordan, Update, VAC, TP3 Forepump tip seal replacement
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[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. |
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Mon May 2 13:30:52 2022, JC, Update, Coil Drivers, Coil Drivers Update
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The DCC has been updated, along with the modified schematic. Links have been attached.
Quote:
18 (9 pairs) Coil Drivers |
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Mon May 2 17:51:30 2022, Anchal, Update, BHD, POX Beam aligned on RFPD, YARM locked
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[Paco, Anchal]
We found that one of the Y1-1037-45P marked mirror that we used was actually curved. So we removed it and used a different Y1-1037-45P mirror,
adjusted the position of the lens and got the beam to land on POX11 RFPD successfully. |
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Tue May 3 13:18:47 2022, JC, Update, VAC, RGA Pump Down
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Jordan, Tega, JC
Issue has been resolved. Breaker on RP1 was tripped so the RP1 button was reporting ON, but was not actually on which continuously tripped the
V6 interlock. Breaker was reset, RP1 and RP3 turned on. The V6 was opened to rough out the RGA volume. Once, pressure was at ~100mtorr, V4 was opened to |
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Tue May 3 21:05:23 2022, yuta, Update, BHD, AS path alignment, removing a lot of green stuff 7x
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[Tega, Yehonathan, Koji, Yuta]
We tried to align AS path this afternoon. |
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Tue May 3 21:07:17 2022, Yehonathan, Update, BHD, BHD Readout simulation
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I feel like there is an instability in my thought process on this. Before my tendency to try to scale and generalize this problem brings me to a full
stop I will make small but quick progress.
First thing is to calculate the noise budget for a simple Michelson. The involved optics are: |
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Wed May 4 13:09:42 2022, Anchal, Update, BHD, IMC table balanced again, IMC is locking, YARM is locking
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[Paco, JC, Anchal]
We balanced the IMC table back again to point that got us 50% of nominal transmission from IMC. Then we tweaked the steering mirror for injection
to IMC to get up to 90% of nominal transmission. Finally, we used WFS servo loop to get to the 100% nominal transmission from IMC. However, we found that |
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Wed May 4 15:08:59 2022, Tega, Update, BHD, XARM alignment to get flashing
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[Yuta, Tega]
We aligned the BS, ITMY, and ETMY PIT and YAW to get the flashing on X-arm whilst also keeping the flashing of Y-arm. From attachment 1, it is
clear that POXDC photodiode is not receiveing any light, so our next task is to work on POX alignment. |
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Wed May 4 18:52:43 2022, Tega, Update, BHD, POP beam too high at POP SM4 on the ITMX chamber
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[Yuta, Tega]
We needed to sort out the POXDC signal so we could work on X-arm alignment. Given that POXDC channel value was approx 6 compared to POYDC value
of approx. 180, we decided to open the ITMX chamber to see if we could improve the situation. We worked on the alignment of POX beam but could not improve |
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Thu May 5 14:46:22 2022, Anchal, Update, BHD, POP beam height lowered, POP_SM4 raised
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[Anchal, JC]
We first aligned the single arm cavity resonance for both arms to get maximum flashing. As we opened the chamber, I found that the POP beam was
mostly hitting the POP_SM4 mirror but was clipping about 2 mm on the top edge. |
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Thu May 5 17:05:31 2022, Tega, Update, BHD, IMC & X/Y-arm alignment
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[Yuta, Tega]
In order to setup POP camera and RFPD on the ITMX table, we decided to first work on the IMC and X/Y-arm alignment.
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Thu May 5 17:50:48 2022, Yehonathan, Update, BHD, BHD Readout simulation
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I have made a Simulink diagram to use in the MICH modeling (attachment) for the homodyne angle detection scheme. The model will be used for each optic
separately and the noises will be combined in quadrature.
I gathered some more bits of info to fill the Simulink boxes. This is what I have so far: |