 Mon Jul 11 10:10:31 2011, Ishwita, Configuration, , AA board 
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The AA board shown in attachment 1 will be used in the seismometer hardware setup. A cartoon of this setup is shown in attachment 2.
BNC connectors are required for the seismometer breakout boxes. So the four-pin LEMO connectors present in the AA board were removed and panel
mount BNC connectors were soldered to it. Red and blue colored wires were used to connect the BNC connectors to the board. Red wire connects the center |
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Sat Jul 16 18:54:05 2011, Ishwita, Manuel, Configuration, Electronics, AA board
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We fixed the anti-aliasing board in its aluminum black box, the box couldn't be covered entirely because of the outgoing wires of the BNC connectors,
so we drilled additional holes on the top cover to slide it backwards by 1cm and then screw it.
We had to fix the AA board box in rack 1X7, but there wasn't enough space, so we tried to move the blue chassis (ligo electro-optical fanout chassis |
 Sun Oct 14 20:51:20 2012, Den, Update, PEM, AA board
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Quote:
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Mon Oct 15 10:14:22 2012, Den, Update, PEM, AA board
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Quote:
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Thu May 9 00:05:12 2013, rana, Koji, Jenne, Summary, LSC, AA and AI change
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We would like to increase the UGF of the PRC loop so as to allow more suppression
of the PRC signal and less pollution of the MICH signal (remember that the PRC/MICH optical gain ratio is huge).
We were already losing phase because of delay in the LSC - SUS digital link. In addition to that, a major source of delay is the analog anti-aliasing |
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Thu Oct 28 04:23:38 2010, rana, Update, IOO, A2L prep
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To get the angle to length signal before the c1ioo processor gets going, we need a length signal. We can use either the error signal or the control signal.
I recommend using the control signal since its not puny. The 4-pin LEMO inputs to the OSEM ADC that Suresh has wired are differential
so we can, in principle, use either the BNC output of the SERVO plug or the 2-pin LEMO output. |
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Thu Jun 21 14:23:22 2018, Udit Khandelwal, Summary, General, A summary of the Tip-TIlt Mirror Holder design changes
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Here’s a quick summary of the Tip-Tilt Design updates (all files are in the dropbox in [TipTiltSus>TT_New]) that I have been working on with
Koji and Steve's help.
1. Plate on top to hold mirror in place: |
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Thu Jun 21 14:57:59 2018, Koji, Summary, General, A summary of the Tip-TIlt Mirror Holder design changes
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> 2. Weighted screw rod at the bottom for tilting the mirror-holder:
Too long. The design of the holder should be check with the entire assembly.
We should be able to make it compact if we heavier weights. |
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Thu Mar 19 02:45:36 2009, Yoichi, Configuration, IOO, A loose wire found for MC1
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I found a loose connection of a wire in the cross-connect between an ADC and the MC1 coil driver's UL bias input.
I tightened it.
To see if this fixes the MC1 drift problem, I will do another round of MC1 drift measurement.
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Thu Mar 19 10:45:43 2009, Yoichi, Configuration, IOO, A loose wire found for MC1
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I attached a 6-hour trend of the MC mirror OSEM signals with the MC unlocked.
The drift of the MC1 is within 20 counts (0.6um in terms of each OSEM).
This is comparable to the other MC mirrors. |
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Wed Dec 4 19:54:27 2019, gautam, Update, LSC, A look to the past
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Trawling through some past elogs, I saw that the ALS noise increase as a function of CARM offset
reduction is not really a new thing (see e.g. this elog). In the past, when we were able to
lock, when the CARM offset is reduced to zero, the arms would "buzz" through resonance. It just wasn't clear to me how much the buzzing was |
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Sat Nov 3 16:20:43 2007, waldman, Summary, OMC, A good day's work 6x
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I followed up yesterday's test of the PZT with a whole mess of characterizations of the PZT control and finished the day by locking the OMC with a PZT
dither lock and a 600 Hz loop. I haven't analyzed any of the data yet, so its not calibrated in physical units and etc. etc. etc. Since a lot of the |
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Fri Mar 4 03:31:35 2011, kiwamu, Update, Green Locking, A first noise budget
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I made a noise budget for the ALS noise measurement that I did a week ago (see #4352).
I am going to post some details about this plot later because I am now
too sleepy. |
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Mon Sep 7 23:49:14 2020, gautam, Update, BHD, A first look at RF44 scheme
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Summary:
Over the last couple of days, I've been working towards getting the infrastructure ready to test out the scheme of sensing (and eventually,
controlling) the homodyne phase using the so-called RF44 scheme. More details will be populated, just quick notes for now before I forget. |
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Tue Sep 8 01:31:43 2020, Koji, Update, BHD, A first look at RF44 scheme
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- Loose fiber coupler: Sorry about that. I could not detect something was loose there, although some of the locks were not tightened.
- S incident instead of P: Sorry about that too. I completely missed that the IMC takes S-pol. |
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Wed Mar 14 13:16:50 2012, kiwamu, Update, LSC, A correction on Noise estimatino in the REFL33Q
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A correction on the previous elog about the REFL33Q noise:
Rana pointed out that the whitening filter's input referred noise should not be such high (I have estimated it to be at 54 nV/sqrtHz).
In
fact the measurement was done in a condition where no laser is on the photo diode by closing the mechanical shutter at the PSL table.
Therefore |
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Mon Feb 9 17:09:51 2009, Yoichi, Update, Computers, A bunch of updates for the network GPIB stuff.
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During the work on ISS, we noticed that netgpibdata.py is very unreliable for SR785.
The problem was caused by flakiness of the "DUMP" command of SR785, which dumps the data from the analyzer to the client.
So I decided to use other GPIB commands to download data from SR785. The new method is a bit slower but much more reliable.
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Thu Feb 18 20:24:48 2021, Koji, Summary, Electronics, A bunch of electronics received
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Todd provided us a bunch of electronics. I went to Downs to pick them up this afternoon and checked the contents in the box. Basically, the boxes are
pretty comprehensive to produce the following chassis
8 HAM-A coil driver chassis
7 16bit Anti-Aliasing chassis
4 18bit Anti-Imaging chassis
5 16bit Anti-Imaging |
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Sat Feb 20 10:01:48 2021, gautam, Summary, Electronics, A bunch of electronics received
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| Will we also be receiving the additional 34 Satellite Amplifier PCBs? |
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Sat Feb 20 16:46:17 2021, Koji, Summary, Electronics, A bunch of electronics received
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We received currently available sets. We are supposed to receive more coil drivers and sat amps, etc. But they are not ready yet.
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Fri Mar 5 00:53:09 2021, Koji, Summary, Electronics, A bunch of electronics received
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Received additional front/rear panels. Updated the original entry and Wiki [Link]
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Fri Mar 5 15:03:28 2021, gautam, Summary, Electronics, A bunch of electronics received
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The PCBs for the D1002593 BIO I/F (5pcs ea of D1001050 and D1001266)
were received (from JLCPCB) today. idk what the status of the parts (digikey?) is.
Quote:
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Fri Mar 5 15:32:53 2021, Koji, Summary, Electronics, A bunch of electronics received
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| The parts will be ordered by Koji The components for the additional BIO I/F have been ordered. |
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Wed Mar 31 03:56:37 2021, Koji, Summary, Electronics, A bunch of electronics received
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| We have received 9x 18bit DAC adapter boards (D1000654) |
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Fri Jun 13 19:09:44 2014, Koji, Update, IOO, A blown fuse found on the euro card crate at 1X2 (IOO) rack.
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[Rana Zach Koji]
We tracked down the MC locking issue to be associated with the power supply problem.
Replacing a fuse which had incomplete connection with the new one, the MC started locking. |
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Mon Apr 4 18:58:44 2011, Bryan, Configuration, Green Locking, A beam of purest green
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We now have green light at the Y end.
The set-up (with careful instructions from Kiwamu) - setting up with 100mW of IR
into the oven. |
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Wed Nov 17 23:45:20 2010, Jenne, Update, SUS, A bad day for suspensions
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[Jenne, Suresh]
Today has been a downright miserable day in the world of suspension work. Thumbs down to that: |
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Tue Dec 8 09:18:07 2009, Jenne, Update, Computers, A *great* way to start the day....
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Opening of ETMY has been put on hold to deal with the computer situation. Currently all front end computers are down. The DAQ AWGs are flashing
green, but everything else is red (fb40m is also green). Anyhow, we'll deal with this, and open ETMY as soon as we can.
The computers take priority because we need them to tell us how the optics are doing while we're in the chambers, fitzing around. We need |
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Mon Oct 22 09:10:07 2012, Steve, Update, VAC, @750Torr
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Quote:
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Sat Jun 6 01:44:53 2009, rob , Update, Locking, ?
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Lock acquisition is proceeding smoothly for the most part, but there is a very consistent failure point near the end of the cm_step script.
Near the end of the procedure, while in RF common mode, the sensing for the MCL path of the common mode servo is transitioned from a REFL 166I
signal which comes into the LSC whitening board from the demodulator, to another copy of the signal which has passed through the common mode board, and |
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Sun Jun 7 04:57:39 2009, Yoichi, Update, Locking, ?
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Quote:
Lock acquisition is proceeding smoothly for the most part, but there is a very consistent failure point near the end |
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Tue Jun 9 23:25:24 2009, rob, Update, Locking, ?
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Quote:
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Tue Oct 13 05:48:39 2015, ericq, Update, LSC, :/
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[ericq, Gautam]
Despite our best efforts, the grappa remains out of reach: the DRFPMI was not locked tonight.
We spent a fair amount of time with the AUX X laser, as it was glitching madly again. |
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Wed Feb 2 03:27:20 2011, Koji, Summary, Green Locking, 85MHz Freq divider
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The freq divider was built and installed in the beat detection path.
Attachment 1: Circuit diagram
Input stage: Wideband RF amp with DC block at the input and the output. The gain is 10dB typ.
2nd stage: Ultra fast |
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Thu Oct 28 03:07:53 2010, kiwamu, Update, Green Locking, 80MHz VCO for green PLL : a health check
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I did a health check for a 80MHz VCO box.
I started taking care with the black VCO box, which has been sitting on the SP table and will be used for converting the green beat signal |
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Fri Oct 29 06:20:20 2010, kiwamu, Update, Green Locking, 80MHz VCO for green PLL : VCO calibration
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I calibrated the VCO frequency as a function of the applied input voltage.
The range is approximately +/- 5 MHz, which is large enough to cover
the arm's FSR of 3.75MHz. |
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Thu Nov 11 17:47:36 2010, kiwamu, Update, Green Locking, 80MHz VCO : improve PLL hold-in range and put a boost
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In order to enlarge the hold-in range I modified the control filter and increased
the gain by factor of 25 in the PLL.
It successfully enlarged the range, |
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Thu Nov 11 13:54:05 2010, kiwamu, Update, Green Locking, 80MHz VCO : about PLL hold-in range
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The hold-in range of the PLL must be greater than +/- 4MHz
in order to bring the arm cavity to its resonance. |
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Mon Nov 8 10:48:58 2010, kiwamu, Update, Green Locking, 80MHz VCO : PLL open loop looks good
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I measured the open loop transfer function of the 80MHz VCO's PLL while locking it to Marconi.
This measurement is for a health check and a characterization of the PLL |
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Mon Nov 8 16:03:46 2010, kiwamu, Update, Green Locking, 80MHz VCO : PLL open loop looks good
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Quote:
I measured the open |
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Wed Aug 11 11:51:45 2010, Gopal , Update, WIKI-40M Update, 8.5.10 - 8.11.10 Weekly Update
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Summary of this Week's Activities:
Thursday, August 5:
X-Displacement Transfer Function Measurement |
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Wed Sep 21 09:04:57 2016, Steve, Update, General, 8 hours recovery progress
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Good 8 hours
Quote:
The misalignment wasn't |
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Tue Oct 4 20:34:20 2011, Katrin, Update, Green Locking, 7kHz Peak in servo input YARM
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[Kiwamu, Katrin]
As reported earlier an oscillation around 7kHz is an the PDH error signal. The lower spectrum show that there is a peak from 6-7kHz.
This peak is somehow dependent on the modulation frequency. This means the peak can be shifted to a higher frequency when the modulation frequency |
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Thu Aug 2 04:58:00 2012, Masha, Update, PEM, 70 Meter Long Guralp 1 Cable
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The parts Jenne and I ordered arrived today, so we made a long cable for Guralp
1 using a 24 + 1 wire 70 meter long cable, a female 37-pin DSub, and a 26-pin milspec. |
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Wed Jul 14 13:03:04 2010, Gopal , Update, WIKI-40M Update, 7.8.10 - 7.14.10 Weekly Update
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Summary of this Week's Activities:
Wed. 7/7: COMSOL Busbar tutorials; began stack design; began base; Viton rubber research
Thurs. 7/8: Completed Viton rubber research; updated materials; finished designing the base layer |
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Wed Aug 4 20:58:22 2010, Gopal, Update, WIKI-40M Update, 7.28.10 - 8.4.10 Weekly Update
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Summary of this week's activities:
7/28: Finished Y-Translational 4-Stack Analysis
"Tapered Cantilever" COMSOL tutorial |
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Wed Jul 28 12:31:00 2010, Gopal, Update, WIKI-40M Update, 7.21.10-7.28.10 Weekly Update
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Summary of this week's activities:
7/21: Frequency Domain Analysis of rectangular bar; discussed with Koji how to convert complex eigenfrequencies into phase factors.
7/23: Created Wiki page about FDA; Journal Club |
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Wed Jul 21 11:57:59 2010, Gopal, Update, WIKI-40M Update, 7.14.10-7.21.10 Weekly Update
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Summary of this week's activities:
7/14: Analytical calculation of Viton spring constant; updated Viton values in models; experimental confirmation of COMSOL eigenfrequencies (single
stack layer) |
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Wed Oct 12 18:54:02 2011, Katrin, Update, Green Locking, 60 Hz oscillation due to broken BNC cable
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There was a 60 Hz and 120 Hz oscillation on the green PDH photo diode output. After a long search, I could identify that
the source was a broken BNC cable which was connected to the photo diode. I exchanged that BNC cable and the 60 Hz
and 120 Hz are gone :-) |
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Sat Dec 17 00:00:03 2011, kiwamu, Update, Green Locking, 60 Hz line nose gone
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Quote from #6126
As |