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ID Date Authorup Type Category Subject
  6474   Sat Mar 31 08:01:07 2012 kiwamuUpdateLSCDRMI measurement

I have measured the sensing matrix of the DRMI although the lock still doesn't stay for a long time.

As for the noise budget, it looks very tough as there are more glitches than that in the PRMI.

In this weekend I will take some more trials in the DRMI lock until I am satisfied.

  6488   Thu Apr 5 06:27:51 2012 kiwamuUpdateLSCAS110 sideband monitor installed

[Jenne / Kiwamu]

 We have installed a broad band PD in the AS path in order to monitor the 110 MHz signal associated with the SRC.

The PD is currently connected to the POP110 demodulation board and it seems working fine.

I know this is confusing but right now the signal appears as "POP110" in the LSC front end model.

 


  • Installed a 50% BS at the AS path
    • The AS beam is split to two path - one goes to AS55 and the other goes to the OSA.
    • The new BS is installed on the way of the OSA branch therefore AS55 isn't affected by the new BS.
  • Installed a PDA10A
    • This is a silicon diode with a bandwidth of 150 MHz, and is fast enough to detect the 110 MHz signals.
    • The 110 MHz signal seems going up to approximately -40 dBm according to a coarse measurement with an RF spectrum analyzer.
    • Also a SMA-style high pass filter, HPF-100, was attached to the output to cut off unnecessary sidebands (e.g. 11, 22 MHz and etc.)
  • Put a long BNC cable, which goes from the PD to LSC rack.
    • The end of the cable at the LSC rack was directly connected to the POP110 demod board.
    • The actual POP110 signal path is currently terminated by a 50 Ohm load and therefore this signal  is unavailable.
  • Adjustment of the demodulation phase
    • The demod phase was adjusted to be 7 deg in the EPICS screen. This phase minimize the Q-signal.
    • Locking PRMI with sidebands resonating makes the AS110 signal ~ a few counts and this level is still noticeable.
    • Perhaps we may need to put an RF amplifier to get the signal bigger.
  6489   Thu Apr 5 07:19:16 2012 kiwamuUpdateLSCDRMI locking

 I tried locking the DRMI to the signal-extraction condition with the new trigger by AS110.

A first thing I tried was : flipping the control sign of the SRCL while keeping the same control setups for the PRCL and MICH.

Occasionally the DRMI was "sort of" locked and hence I believe this setup must be a good starting point.

As a next step I will try some different gains and demodulation phase to make it more lockable.

 


(Time series)

DRMI_2012Apr4_edit.png

 The picture above is time series of some signals when the DRMI was barely locked.
The red arrows indicate the durations when the DRMI was sort of locked.
 (Green curve) REFLDC becoming a high value state, which indicates that the carrier is anti-resonant.
 (Red curve) ASDC becoming dark, which indicates the MICH is in the vicinity of the dark condition.
 (Brown curve) AS110 becoming a high value state, which means the 55 MHz sidebands got amplified by the SRCL.
 (Blue curve) POP22 becoming a high value state, which indicates that the 11 MHz sidebands are resonating in the PRC.
 
According to the measurement of AS110 when PRMI was locked (#6488), the AS110 signal went up to ~ 1 counts or so.
On the other hand when the DRMI was locked the AS110 went to up more than 10 counts as shown in the plot above.
Therefore at least some kind of signal amplification is happening for the 55 MHz sidebands in the SRC.
Looking at the AS CCD, I found that the beam looked like a TEM01 mode (two beam spots at top and bottom) every time when the DRMI was locked.
 
(settings)
  • REFL33I => PRCL  G = -0.2
  • AS55Q => MICH    G = -6
  • AS55I => SRCL     G = 1   (G = -50 for the signal recycling condition)
  • AS55 demod phase = 17 deg
  6506   Sat Apr 7 01:56:05 2012 kiwamuUpdateLSCOSA signal in DRMI condition

It wasn't a dream or illusion -- I was locking the DRMI to the right condition last Wednesday (#6489).

Here is a snap shot of the AS-OSA signal taken today when the DRMI was locked with the same control settings (#6489).

The blue curve is data taken when the PRMI was locked for comparison.

You can see that both the upper and lower 55 MHz sideband are amplified by the SRC.

OSA.png

 

(Some notes)

Currently SRM is slightly misaligned such that the MICH optical gain at AS55Q doesn't increase so much with the presence of SRM.

With this condition I was able to acquire the lock more frequently than how it used to be on the Wednesday.

The next step is to gradually align SRM, to optimize the controls and to repeat this process several times until SRM is fully aligned.

Quote from #6489

A first thing I tried was : flipping the control sign of the SRCL while keeping the same control setups for the PRCL and MICH.

Occasionally the DRMI was "sort of" locked and hence I believe this setup must be a good starting point.

  6508   Sat Apr 7 06:58:34 2012 kiwamuUpdateLSCDRMI lock : lost good alignment

Somehow I lost the good alignment, where the lock can be frequently acquired and hence I didn't go further ahead.

I will try locking the DRMI during the weekend again. My goal is to take time series when the DRMI is being locked and sensing matrix.

Quote from #6506

Currently SRM is slightly misaligned such that the MICH optical gain at AS55Q doesn't increase so much with the presence of SRM.

With this condition I was able to acquire the lock more frequently than how it used to be on the Wednesday.

The next step is to gradually align SRM, to optimize the controls and to repeat this process several times until SRM is fully aligned.

 

  6512   Mon Apr 9 18:18:14 2012 kiwamuUpdateLSCDRMI time series

Here is a time series when the DRMI is being locked.

You can see that the AS110 goes up because the SRCL is engaged and amplifies the 55 MHz sidebands.

 time_series1.png

  7534   Fri Oct 12 01:56:26 2012 kiwamuUpdateGeneralAlignment situation of interferometer

[Koji / Kiwamu]

 We have realigned the interferometer except the incident beam.

 The REFL beam is not coming out from the chamber and is likely hitting the holder of a mirror in the OMC chamber.

So we need to open the chamber again before trying to lock the recycled interferometers at some point.

 

--- What we did

  •  Ran the MC decenter script to check the spot positions.
    • MC3 YAW gave a - 5mm offset with an error of about the same level.
    • We didn't believe in this dither measurement.
  •  Checked the IP-POS and IP-ANG trends.
    • The trends looked stable over 10 days (with a 24 hours drift).
    • So we decided not to touch the MC suspensions.
  • Tried aligning PRM
  • Found that the beam on the REFL path was a fake beam
    • The position of this beam was not sensitive to the alignment of PRM or ITMs.
    • So certainly this is not the REFL beam.
    • The power of this unknown beam is about 7.8 mW
  • Let the PRM reflection beam go through the Faraday
    • This was done by looking at the hole of the Faraday though a view port of the IOO chamber with an IR viewer.
  • Aligned the rest of the interferometer (not including ETMs)
    • We used the aligned PRM as the alignment reference
    • Aligned ITMY such that the ITMY reflection overlaps with the PRM beam at the AS port.
    • Aligned the BS and SRM such that their associated beam overlap at the AS port
    • Aligned ITMX in the same way.
    • Note that the beam axis, defined by the BS, ITMX  and SRM, was not determined by this process. So we need to align it using the y-arm as a reference at some point.
    • After the alignment, the beam at the AS port still doesn't look clipped. Which is good.

 

---- things to be fixed

   - Align the steering mirrors in the faraday rejected beam path (requires vent)

   - SRM oplev (this is out of the QPD range)

   - ITMX oplev (out of the range too)

  8866   Thu Jul 18 01:10:00 2013 kiwamuUpdateGreen LockingALS Y performance with the new whitening filter

 

Awesome !

  9051   Thu Aug 22 10:20:32 2013 kiwamuUpdateLSCDRMI Locked for 1+ minute!!!!!!

Wonderful ! I like the video -- the spatial mode looks pretty clean and much cleaner than what I observed in the old days.

  2631   Tue Feb 23 13:37:04 2010 kiwamu and steveConfigurationVACventing the 40m vac envelope

Kiwamu and Steve have started venting the 40m vacuum envelope.

Preparation:

centered oplevs at resonating cavities,

ITM references were set by green pointer from the ends by Koji,

closed  PSL shutter and placed manual block into beam path,

checked  jamnuts in locked positions on bellows,

turned  HV off at PZT-Jena "steering mirror" power supply and OMC HV ps

checked  particle counts,

switched oplev servos off,

set up N2 cylinder to start vent from 1e-6 Torr to 25 Torr,

have ~ 6 cylinders of instrument grade compressed air to bring envelope from 25 Torr to 760 Torr

 

All three cranes were wiped off today.

 

  2636   Tue Feb 23 19:07:43 2010 kiwamu and steveConfigurationVACvent is completed

Quote:

Kiwamu and Steve have started venting the 40m vacuum envelope.

Preparation:

centered oplevs at resonating cavities,

ITM references were set by green pointer from the ends by Koji,

closed  PSL shutter and placed manual block into beam path,

checked  jamnuts in locked positions on bellows,

turned  HV off at PZT-Jena "steering mirror" power supply and OMC HV ps

checked  particle counts,

switched oplev servos off,

set up N2 cylinder to start vent from 1e-6 Torr to 25 Torr,

have ~ 6 cylinders of instrument grade compressed air to bring envelope from 25 Torr to 760 Torr

 

All three cranes were wiped off today.

 

 Kiwamu has completed the vent.

Attachment 1: vent2010feb23.jpg
vent2010feb23.jpg
  2444   Tue Dec 22 11:23:51 2009 kiwamu, SteveUpdateIOOMC relocked

In this morning I found MC unlocked.

Steve restored the watchdogs before I found that.

Then I relocked MC and now MC is locked and working well.

The reflected DC power is ~0.38, which is usual number.

 

  2707   Wed Mar 24 04:22:51 2010 kiwamu, mattUpdateGreen Lockingtwo NPRO PLL

Now some pedestals, mirrors and lenses are left on the PSL table, since we are on the middle way to construct a PLL setup which employs two NPROs instead of use of PSL laser.

So Please Don't steal any of them.

  2712   Wed Mar 24 15:59:59 2010 kiwamu, mattUpdateGreen Lockingleave PLL locked

Matt checked it in this morning and he found it's been locked during the night.

 

 

  2706   Wed Mar 24 03:58:18 2010 kiwamu, matt, kojiUpdateGreen Lockingleave PLL locked

We are leaving the PLL as it is locked in order to see the long term stability. And we will check the results in early morning of tomorrow.

DO NOT disturb our PLL !!

  


(what we did)

After Mott left, Matt and I started to put feedback signals to the temperature control of NPRO.

During doing some trials Matt found that NPRO temperature control input has an input resistance of 10kOhm.

Then we put a flat filter ( just a voltage divider made by a resistor of ~300kOhm and the input impedance ) with a gain of 0.03 for the temperature control to inject a relatively small signal, and we could get the lock with the pzt feedback and it.

In addition, to obtain more stable lock we then also tried to put an integration filter which can have more gain below 0.5Hz.

After some iterations we finally made a right filter which is shown in the attached picture and succeeded in obtaining stable lock.

 

 

 

Attachment 1: DSC_1402.JPG
DSC_1402.JPG
  2714   Thu Mar 25 17:29:48 2010 kiwamu, mottUpdateGreen LockingPLL two NPROs

In this afternoon, Mott and I tried to find a beat note between two NPROs which are going to be set onto each end table for green locking.

At first time we could not find any beats. However Koji found that the current of innolight NPRO was set to half of the nominal.

Then we increased the current to the nominal of 2A, finally we succeeded in finding a beat note.

Now we are trying to lock the PLL.

P.S. we also succeeded in acquiring the lock

 

nominal setup
  innolight  lightwave
T [deg] 39.75 37.27
current [A] 2 2
laser power [mW] 950 700


  2462   Mon Dec 28 23:56:44 2009 kiwamu, ranaUpdateComputersadd the HILO drift channels to the burt

The HIGH and LOW channels are added into the burt request file "/target/c1losepics/autoBurt.req".

These values are used to colorize the alarm texts in the "C1DRIFT_MONITOR.adl" like a threshold. (the screenshot attached)

Hereafter these values will be automatically restored by the burt.  Happy !

Attachment 1: Screenshot_DRIFTMON.png
Screenshot_DRIFTMON.png
  2690   Sun Mar 21 20:08:20 2010 kiwamu, ranaUpdatePSLEOM wasit size

We are going to set the waist size to 0.1 mm for the beam going through the triple resonant EOM on a new PSL setup.

When we were drawing a new PSL diagram, we just needed to know the waist size at the EOM in order to think about mode matching.

waist.png

This figure shows the relation between the waist size and the spot size at the aperture of the EOM.

The x-axis is the waist size, the y-axis is the spot size. It is clear that there is a big clearance at 0.1 mm waist size. This is good.

Also it is good because the waist size is much above the damage threshold of the EO crystal (assuming 1W input).

The attached file is the python code for making this plot.

Attachment 2: waist.py.zip
  2464   Tue Dec 29 04:28:27 2009 kiwamu, rana, haixingUpdateCamerasNew Video Switch Installed

We have installed the new Video Matrix.

Its still in an intermediate state, so don't try to "fix" anything before Kiwamu and I get back onto it in the afternoon.

The status so far is that we have removed the old switch (it was a 256 input x 128 output !! mux)  and installed the new one in the same rack. We have hooked it up to the CDS network and have set up its matrix by using the web interface (i.e. NOT EPICS).


Along the way, we discovered that there is lack of impedance matching in the video all over the 40m. Video signals are RF and need to be treated that way. The PSL signals are T'd around and sent on 50 Ohm cables to high impedance monitor inputs.

We should eliminate any switches besides the new one (called Luciana) and control the PSL's Video Monitor from the main MUX interface. No more Rogue Video Switches.

 


Another couple of things we have found is about RCR camera.

(1) The long cable which connects the RCR camera box and the video matrix doesn't work. Although the signal is alive and we can see it by the local tv monitor nearby PSL.

(1) The reflected beam going to the camera is too weak to see in the monitor.  We found a strange polarized cube splitter in front of the camera. We should modify it sooner or later.

  2538   Thu Jan 21 11:08:30 2010 kiwamu, steveUpdateVACDry Pump replacement

 This morning I and Steve replaced  the dry fore pump of TP3, which is located under the y-arm.

After replacing it we confirmed vacuum normal condition. The fore line pressure of TP3 went down to 11 mTorr from 750 mTorr

  Attached picture is new pump after setup.

Attachment 1: DSCN0428.JPG
DSCN0428.JPG
  5261   Thu Aug 18 10:17:04 2011 kiwamu, steveUpdateSUSoplevs reestablished at Vertex

Kiwamu and Steve, from yesterday

PRM and BS oplev paths were relaid after setting 1/2 OSEM voltages. The incident beam on suspended optics are centered  within  ~ +- 2 mm

I noticed many unvected ss screws are used on the big Al table tops. The SS 1/4-20 screws

 used on the optical tables in vacuum MUST be VENTED!

Also, please use  SS clamps. Replace aluminum ones when you can. We have plenty baked ones.

 

 

  2676   Tue Mar 16 05:10:39 2010 kojiUpdateEnvironmentEarthquake, Mag 4.4

Some of the suspensions got watchdog tripped -> enabled -> damped.

The MC mirrors got slightly misaligned.

 

Attachment 1: 100316_MC_SUS.png
100316_MC_SUS.png
  2894   Fri May 7 11:21:49 2010 kojiUpdate40m UpgradingNew improved design for the 11MHz photodiode

How much is the width?

Quote:

 This should be better. It should also have larger resonance width.

 

  3577   Wed Sep 15 16:00:26 2010 koji, steveUpdateMOPA 

We removed the Lightwave MOPA Controller from 1X1 (south)  It was a real painfully messy job to pull out the umbilical.

Note: the umbilical is shading it plastic cover. It is functional but it has to be taken out side and cleaned. Do not remove it from it's plastic bag in a clean environment.

Now Joe has room for IOO chassy  in this rack.

We also removed the Minco temp controller and ref. cavity ion pump power supply.

 

  3578   Wed Sep 15 16:12:35 2010 koji, steveUpdateMOPAMOPA Controller is taken out of the PSL rack

We removed the Lightwave MOPA Controller, PA#102, NPRO206 power supply to make room for the IOO chassy at 1X1 (south) rack.

The umbilical cord was a real pain to take out. It is shading its plastic cover. The unused Minco was disconnected and removed.

The ref. cavity ion pump controller- power supply was temporarily taken out also.

Attachment 1: P1060843.JPG
P1060843.JPG
  3604   Fri Sep 24 00:56:35 2010 koji, taraUpdateElectronicstesting TTFSS

We found that a transistor was broken from yesterday spark too. We partially fixed TTFSS, and it should be enough for  testing purpose.

 

From yesterday test, we found that the RF amplifier for LO signal was broken. There was no spare at the electronic shop at Downs,

so we shorted the circuit for now.  Another part which was broken too was a transistor, Q3 PZT2222A, on D0901846.

It was removed and two connections, which are for Q3's 1 and 3 legs, are shorted. Now the voltages out from the regulators are back to normal.

 

We are checking a MAX333A switch, U6A on D0901894. it seems that the voltage that controls the switch disappears.

There might be a bad connection somewhere. This will be investigated next.

  3607   Fri Sep 24 23:47:10 2010 koji, taraUpdateElectronicstesting TTFSS

  Q3, a PZT2222A transistor, on D0901846 is replaced by a GE-82. However, the board is still not fully function.

 

Since Q3, PZT2222A, was broken, I went to Wilson house and got some SP3904's for replacement. But somehow, I broke it during

installation, and did not notice it, and resumed the test. When I got to test 8 on the list, the TTFSS did not work as specified.

Koji checked and found out that -15V, Nref, Vref voltages output did not work correctly. So the SP3904 I installed was removed

and replaced with another SP3904 by Koji, and Vref is working. 

Q4 transistor is broken as well and it was replaced by GE 82.

Q1 might be broken too since -15V out is not working.

I'll go to Wilson house to get more transistors next week.

 

After the broken parts have been replaced, I have to make sure that I separate the power supply board from the rest of the circuit and

check if all V outputs are  working, then reconnect the board and check if the current input is reasonable before resume the test.

I hope the wrong input voltage problem today wouldn't damage anything else.

 

  3617   Tue Sep 28 21:11:52 2010 koji, taraUpdateElectronicsFixing the new TTFSS

We found a small PCB defect which is an excess copper shorting circuit on the daughter board,

it was removed and the signal on mixer monitor path is working properly.

 

 We were checking the new TTFSS upto test 10a on the instruction, E1000405 -V1. There was no signal at MIXER mon channel.

It turned out that U3 OpAmp on the daughter board, D040424, was not working because the circuit path for leg 15 was shorted

because of the board's defect. We can see from fig1 that the contact for the OpAmp's leg (2nd from left) touches ground.

We used a knife to scrap it out, see fig 2, and now this part is working properly.

 

Attachment 1: before.jpg
before.jpg
Attachment 2: after.jpg
after.jpg
Attachment 3: before.jpg
before.jpg
Attachment 4: after.jpg
after.jpg
  4777   Wed Jun 1 13:33:22 2011 koji, taraUpdateElectronicsTTFSS #7

We replaced GE81 by PZT2907A (PNP transistor) in TTFSS #7, it's working fine.

  Last time I broke Q4 transistor, which is used in the low noise power module for TTFSS, (see the schematic) and could not find another PZT2907A, so GE81 was used temporarily. Now we changed it back to PZT2907A as designed.  I tested it by checking the voltage outputs of the board. It works fine, all voltage outputs are correct. I labeled one of the slot on the blue cabinet tower and kept the rest of the transistors there.

q4.png

Quote:

I brought TTFSS set #7 to 40m and kept it in the electronic cabinet.

note that Q4 transistor has not been replaced back to PZT2907A yet. It's still GE82.

Q3 is now pzt3904, not PZT2222A.

 

 

  3596   Thu Sep 23 02:23:04 2010 koji,taraSummaryElectronicsTesting new TTFSS

I tested the new table top frequency stabilization system(TTFSS),
I haven’t finished it yet, and accidentally fried one amplifier in the circuit.

We received three sets of a new TTFSS system which will replace the current FSS.
It needs to be checked that the system works as specified before we can use it.

- Result

I followed the instruction written on E10000405-v1
The first test inspected how much the currents were drawn from the +/- 24 V power supply.
+24 V drew 350 mA and -24 V drew 160 mA as shown on pwr supply’s current monitor.
They exceeded the specified value which was 200 +/- 20 mA, but nothing went wrong during the test.
Nothing got overheated, all voltage outputs were correct so I proceeded.
I have gone down the list to 6, and everything works as specified.

- Correcting the document for the test procedure

I found a few errors on the instruction document. I’ll notify the author tomorrow.

- How GVA-81 amplifier on D0901894 rev A got fried

During the test, I used a mirror on a stick that looked like a dental tool to see under the board.
Unfortunately, the steel edge touched a board and caused a spark. The voltage on -24 dropped to -16.
I think this happened because the pwr supply tried to decrease the current from shorted circuit,
as I shorted it only short time ( a blink of an eye), it could not reduce the voltage to zero.
When I was checking the power supply and about to adjust the voltage back to the right value
(about 4-5 seconds after the spark,) smoke came out of the circuit.

Koji investigated the circuit and found that a GVA 81 amplifier was broken.

This was checked by applying 5V to the amp, and slightly increasing the current.
The voltage dropped to zero as the amp was broken, so its circuit was shorted.

I’ll see if I can replace this at EE lab at Downs.
If I cannot find a spare one, I’ll replace it with a resistor and resume the test procedure.
Because it amplifies LO signal, which won’t be used during the test.

  7952   Tue Jan 29 10:59:37 2013 lazy personFrogsGeneralbetter plan

 

 I propose we work around this problem with giant flip-flops.  These are in the vein of the take-off-your-shoes-and-put-on-Crocs, without the taking off your shoes part.  They're a little annoying on the sticky mats, but otherwise great.  They are also super easy to put on and take off without hands, so there's no excuse for wearing them around the control room. 

I propose we buy many pairs of the smalls in green (since we already have one green small...they are big on me, so should be just right for most people), and a few mediums in, say, blue, and a few larges in black, and then maybe a few extra larges in green for people with extraordinarily large feet (they only have 3 colors).  Then we can keep a few pairs of each by each door to the lab, and have no more tracking dirty control room filth into the lab.

  4752   Fri May 20 01:02:50 2011 loose connection hunterUpdateSUSloose connection on ETMY rack

The UL signal of the shadow sensor on ETMY went to zero this evening.

This was due to a loose connection on the cross connection board on the 1Y4 rack.

In order to make them tighten, a combination of stand-offs and screws were installed on the connectors. They won't be loose any more.

ETMY_loose.png

  3701   Tue Oct 12 23:35:12 2010 mafaldaUpdateComputerscelan-installed CentOS 5.5 on mafalda

Quote:

I clean-installed CentOS 5.5(32bit) on mafalda.
No firewalls, no SELinix.

 Yuta has removed my ethernet connection. Help me!!!

rossa:mDV>ping mafalda
PING mafalda.martian (192.168.113.23) 56(84) bytes of data.
From rossa.martian (192.168.113.215) icmp_seq=2 Destination Host Unreachable
From rossa.martian (192.168.113.215) icmp_seq=3 Destination Host Unreachable
From rossa.martian (192.168.113.215) icmp_seq=4 Destination Host Unreachable

--- mafalda.martian ping statistics ---
5 packets transmitted, 0 received, +3 errors, 100% packet loss, time 3999ms
, pipe 3

  8769   Thu Jun 27 17:49:17 2013 manasaUpdateGreen Lockingc1als model edited

Quote:

 Could be that this is OK, but it doesn't yet make sense to me. Can you please explain in words how this manages to apply the calibration rather than just add an extra gain to the phase tracking loop?

The calibration is applied by adding an extra gain. But, I missed the point that I should be doing this outside the phase-tracking loop....my BAD .

So I modified the model such that the calibration is done without disturbing the phase tracking loop.

Right now, epics input 'PHASE_OUT_CALIB' accepts the calibration and we get the calibrated phase tracker output converted from deg to Hz at 'PHASE_OUT_HZ'.  I have also made it a DAQ channel to be used with dataviewer and dtt.

medm screens have been modified to accommodate these additions to the phase tracker screen. I used Yuta's phase tracker calibration data in elog to set PHASE_OUT_CALIB in the medm screens.

ALS_PHASEcalib.png

BEATX_FINE.png

  8772   Thu Jun 27 19:17:03 2013 manasaUpdateLSCXarm ALS out-of-loop noise

Measured frequency noise is ~10Hz/rtHz @100Hz. 

Measure the out-of-loop noise of Xarm ALS:

1. The X-arm was locked for IR using PDH error signal.

2. 'CLEAR HISTORY' of the phase tracker filters.

3. Measured the power spectrum of the phase tracker output. I have used the newly created calibrated channel "PHASE_OUT_DQ. So the phase tracker output now reads in Hz.

Discussion:

The measurement was done with beat note frequency at ~40MHz. The flat noise level of 10Hz/rtHz from 20-100Hz (in plot 2) is not good. We should investigate as to what sets this noise level. The spike at 60Hz is because the 60Hz frequency comb filter was not enabled.

I plan to the following to get a clearer outlook
1. Connecting the beat box to an RF source and measure the noise levels for a range of frequency inputs to the beatbox.
2. Measure the noise at C1:ALS-BEATX_FINE_I_IN1 (before the antiwhitening filters) and check whether the new whitening filters has done anything good with respect to minimizing the DAQ noise.

 

Attachment 1: ALS_OoL.pdf
ALS_OoL.pdf
Attachment 2: ALS_OoL1.pdf
ALS_OoL1.pdf
  8779   Fri Jun 28 02:12:21 2013 manasaUpdateLSCPRMI + X arm ALS

X arm stabilized using ALS while PRMI stayed locked

[Rana, Lisa, Jenne, Manasa]

Attachment 1

Time series : ALS enabled at t = 0 and disabled at t = 95s

PRMI_XALS_Jun28.png

What we did:
1. Jenne will elog about ASC (POP QPD) updates.
2. Found the beat note between Xarm green and PSL green.
3. Stabilized arm fluctuation by enabling ALS servo.
4. Scanned the arm for carrier resonance by ramping on the offset and set the offset such that we had IR resonating (TRX fluctuated between 0.1 and 0.8 counts).
5. Disabled the ALS servo and locked PRMI using AS55 for MICH and REFL33 for PRCL.
6. Enabled ALS.

Discussion:
Enabling ALS to detune the arm out of resonance kept PRMI locked  (currently for a span of few tens of seconds). However we could not see PRMI locked as stably compared to when the arms are misaligned. Everytime the offset was set IR to resonate, the PRMI was kicked out of lock.

Also there is some leakage at the arm transmission when PRMI was locked. The leakage was visible at ETMX transmission as flashes in different higher order modes indicating the not-so sufficient ALS stability. The leakage sets an offset at TRX measuring 0.01-0.05 counts.

To do list:
The ALS_OFFSETTER1 has to be calibrated in FSR. We were giving random offsets to do the offset scan.

Misc:
Installed a filter before ETMXT camera to remove the refl green. (Note to myself: The filter needs to go on a better mount/adapter).

  8794   Wed Jul 3 10:39:25 2013 manasaUpdateIOOMC aligned and WFS enabled

I found WFS had been left disabled from sometime yesterday. I don't see anyone mentioning  when and why they had turned OFF the WFS servo.

I aligned MC and turned ON the WFS servo. MC is back.

  8807   Mon Jul 8 21:46:31 2013 manasaUpdateGreen LockingBeatbox

[Koji, Manasa]

I wanted to investigate on the ALS electronics(in particular the beatbox and the phase tracker) and find out if the beatbox is showing a linear behavior
as we expect it to and as to why we have been seeing sudden jumps at the phase tracker output.

I have been using the Xarm part of the beabox.
I used Marconi as well as signal generator to do frequency sweep/modulation at the RF input of the beatbox and looked at the I_MON output of the beatbox.

We observed sudden jumps in the beatbox output from time to time while we either varied the carrier frequency or the RF amplitude.
Also the beatbox output shows high frequency oscillations at ~95MHz (source unknown). It is for sure that the beatbox is not behaving the way it should
but we could not tell more or troubleshoot with the beatbox mounted on the rack.

I am going to let Annalisa do her Y arm ALS scan tonight and pull out the beatbox tomorrow to fix it.

  8818   Wed Jul 10 02:10:41 2013 manasaUpdateGreen LockingBeatbox gets a makeover

Quote:

[Koji, Manasa]

I wanted to investigate on the ALS electronics(in particular the beatbox and the phase tracker) and find out if the beatbox is showing a linear behavior
as we expect it to and as to why we have been seeing sudden jumps at the phase tracker output.

I have been using the Xarm part of the beabox.
I used Marconi as well as signal generator to do frequency sweep/modulation at the RF input of the beatbox and looked at the I_MON output of the beatbox.

We observed sudden jumps in the beatbox output from time to time while we either varied the carrier frequency or the RF amplitude.
Also the beatbox output shows high frequency oscillations at ~95MHz (source unknown). It is for sure that the beatbox is not behaving the way it should
but we could not tell more or troubleshoot with the beatbox mounted on the rack.

I am going to let Annalisa do her Y arm ALS scan tonight and pull out the beatbox tomorrow to fix it.

 The beatbox output showed high frequency oscillations during the troubleshooting process yesterday. I removed the beatbox from the rack. With no RF inputs, just powering the beatbox showed these high frequency oscillations at the beatbox output. This confirms that these oscillations are from the op-amp AD829JR. I replaced these with low noise OP27G. Also I removed the AD829JR that were soldered to the frequency divider and comparator which are not being used. Output buffer U10 was also removed.

After replacing with OP27G, I rechecked the beatbox with and without the RF input. There were no more high frequency contaminations and beatbox seemed to behave as it is supposed to when a frequency modulated RF input is fed. I put the beatbox back on the rack and did  a quick recheck.

Before (top) and after (bottom) pictures

IMG_0842.JPGIMG_0844.JPG

IMG_0845.JPGIMG_0846.JPG

 

  8820   Wed Jul 10 11:27:02 2013 manasaUpdateGreen LockingX arm beatnote found

I found the beat note for X arm. I did not change anything this morning (to the best of my knowledge). Hooking up the spectrum analyzer, I could find the beatnote signal at the PD RF output, after the amplifier and also at the MON port of the beatbox. I still don't know what changed from the last night set of trials

  8824   Thu Jul 11 00:30:27 2013 manasaUpdateGreen LockingX arm ALS post-beatbox makeover

I ran a series of diagnostics on the X arm ALS to look at how the beatbox behaves after the makeover.

Diagnostic tests run:
1. X arm ALS in-loop spectrum
2. X arm ALS out-of loop spectrum
3. X ALS scan of the X arm cavity

The noise suppression looks better after the makeover at the lower frequencies. To suppress the noise at high frequencies, we would have to add more whitening filters.

Attachment 1: XALS_inloop.pdf
XALS_inloop.pdf
Attachment 2: XALS_scan.pdf
XALS_scan.pdf
Attachment 3: ALS_outloop.pdf
ALS_outloop.pdf
  8826   Thu Jul 11 07:34:42 2013 manasaUpdateLSCYarm held nicely on IR resonance with ALS, PRMI+arm attempt

Quote:

We knew that the Yarm was well aligned, since our IR resonance was > 0.98, but it had been a while since we had aligned the X arm. 

 The X arm was locked with TRX>0.98 earlier last night while I was measuring the out of loop noise of the phase tracker.

  8835   Fri Jul 12 12:30:47 2013 manasaUpdateGeneral Halogen illumination cables disconnected

Quote:

Alex and Steve,

Old halogen chamber illuminator cabling disconnected and potenciometer board removed at 1Y1 in order to give room for pd calibration fibre set up.

 During the process, they had also removed the power cable to the ITMY camera. Steve and I fixed this...so the camera is back.

  8837   Fri Jul 12 12:51:16 2013 manasaUpdateLSCPRMI + ALS automation

Quote:

We talked about how it should be automated.

We'll gradually offload the switching works on scripts.

 Here is the list of automations that we need to work on for less hectic PRMI+ALS trials.

1. Enable/Disable ASC when PRMI is locked/unlocked.

2. Smooth transfer from REFL33/AS55 to REFL165 when PRMI is locked.

3. Change actuation from the ITMs to BS and PRM after PRMI lock.

4. Enable ALS.

5. IR resonance scan using ALS.

  8841   Fri Jul 12 23:13:32 2013 manasaUpdateGreen LockingALS sensor noise

[Annalisa, Koji, Manasa]

In order to improve the ALS stability we went ahead to check if we are limited by the sensor noise of ALS.

What we did:
RF signals similar to the beatnote were given at the RF inputs of the beatbox.
The frequency of the RF signal was set such that I_OUT was zero (zero-crossing point of the beatbox).
We measured the noise spectrum of the phase tracker output.

Measurements:

Plot 1: X ALS noise spectrum
Plot 2: Y ALS noise spectrum

Discussion:

The X arm ALS noise is not limited by the sensor noise...which means we shoudl come up with clever ideas to hunt for other noise sources.
But this does not seem to be the case for the Y arm ALS. The Y arm part of the beatbox is noisy for frequencies < 100Hz.


After looking into the details and comparing the X and Y arm parts of beatbox, it looks that amplitude of the beat signal seem to affect the Y arm ALS noise significantly and changes the noise spectrum.

To do:
Investigate the effect/limitations of amplitude of the beatnote on the X arm and Y arm beatbox.

Attachment 1: X_ALS_0712.pdf
X_ALS_0712.pdf
Attachment 2: Y_ALS_0712.pdf
Y_ALS_0712.pdf
  8858   Tue Jul 16 15:22:27 2013 manasaUpdateCDSFront ends back up

c1sus, c1ioo, c1iscex and c1iscey were down. Why? I was trying to lock the arm and I found that around this time, several computers stopped working mysteriously. Who was working near the computer racks at this time???

I did an ssh into each of these machines and rebooted them sudo shutdown -r now

But then I forgot / neglected/ didn't know to bring back some of the SLOW Controls computers because I am new here and these computers are OLD. Then Rana told me to bring them back and then I ignored him to my great regret. As it turns out he is very wise indeed as the legends say.

So after awhile I did Burtgooey restore of c1susaux (one of the OLD & SLOW ones) from 03:07 this morning. This brought back the IMC pointing and it locked right away as Rana foretold.

Then, I again ignored his wise and very precious advice much to my future regret and the dismay of us all and the detriment of the scientific enterprise overall.

Later however, I was forced to return to the burtgooey / SLOW controls adventure. But what to restore? Where are these procedures? If only we had some kind of electronics record keeping system or software. Sort of like a book. Made of electronics. Where we could LOG things....

But then, again, Rana came to my rescue by pointing out this wonderful ELOG thing. Huzzah! We all danced around in happiness at this awesome discovery!!

But wait, there was more....not only do we have an ELOG. But we also have a thing called WIKI. It has been copied from the 40m and developed into a thing called Wikipedia for the public domain. Apparently a company called Google is also thinking about copying the ELOG's 'find' button.

When we went to the Wiki, we found a "Computer Restart Procedures" place which was full of all kinds of wonderous advice, but unfortunately none of it helped me in my SLOW Controls quest.

 

Then I went to the /cvs/cds/caltech/target/ area and started to (one by one) inspect all of the targets to see if they were alive. And then I burtgooey'd some of them (c1susaux) ?? And then I thought that I should update our 'Computer Restart Procedures' wiki page and so I am going to do so right now ??

And then I wrote this elog.

 

  8878   Fri Jul 19 12:00:12 2013 manasaUpdateGreen LockingALS Y performance with the new whitening filter

Quote:


(Manasa downloaded the 2k sampled data so that we can use this for presentations.)

 Path to data (retreived using getdata)

/users/manasa/data/130717/YALS_scan

  8879   Fri Jul 19 12:02:18 2013 manasaUpdateLSCPRMI+Y arm ALS success!

Data retrieved using getdata (30 minutes trend) saved at

/users/manasa/data/130717/PRMI_YALS

  8880   Fri Jul 19 12:23:34 2013 manasaUpdateCDSCDS FE not happy

I found CDS rt processes in red. I did 'mxstreamrestart' from the medm. It did not help. Also ssh'd into c1iscex and tried 'mxstreamrestart' from the command line. It did not work either.

I thought restarting frame builder would help. I ssh'd to fb. But when I try to restart fb I get the following error:

controls@fb ~ 0$ telnet fb 8088
Trying 192.168.113.202...
telnet: connect to address
192.168.113.202: Connection refused

 

Screenshot-Untitled_Window.png

  8894   Mon Jul 22 21:23:04 2013 manasaUpdateGeneralVent preparation - In progress

[Gautam, Manasa]

Green steering mirrors have been swapped with PZT mirrors at the X end table. We aligned the green to the X arm.

X arm green transmission +PSL green  ~ 0.95

That's better than before the swap...woohooo

ELOG V3.1.3-