1: Pilot unit beam diverter was replaced with a production unit.

IR high reflector on the old diverter was put in the new one, but we removed a translucent-ish black glass and installed a standard black glass.

2. TMS ISC table + telescope was reattached to the top mass and suspended.

Some circus of putting the tele+table on a bench and then picking it up from the opposite side was necessary due to space constraint under the test end. As a result, one Genie lift is right now trapped between the roll up door side of the clean room and the TMS/ETM. I hope this doesn't bother others.

One of the TMS tele F2 mirror clamp was pressed against the tele lift tooling when we're lowering the tele/table.

After the tele/table was freed and was suspended, I inspected F2 mirror. All clamps were still touching the mirror, and all ball point contacts (three from the side and three from the back) were all touching the mirror sourface also. Looks good.

3. Fall protection wire and temporary alignment stabilization tooling were installed.

4. For tomorrow: Cable up QPDs, picos and beam diverter, balance the entire structure, and completely free up everything.

That could be a day's job. After that, we need IAS to measure the position of the TMS input aperture. We need to find the right tooling for that at EX lab. The one we used for EX probably doesn't work as EY is a pilot unit and it has somewhat different screw hole locations, so we need to find the old tooling.

Evan, Paul

Yesterday we took beam size measurements on ISCT of the beam directly reflected from ITMY. I didn't get around to processing the data until later, hence the late post.

The results were: ITMY direct reflected beam size = 2329um (x-axis), 2398um (y-axis)

As expected, the ITMY direct relfected beam size is smaller than the ITMX direct reflected beam size, but only by 6% or so. I will check against my model to see if the difference in sizes makes sense quantitatively, though the unknown non-thermal lens in ITMY may make it difficult to draw a strong conclusion from this.

I attach again plots of the ASD of the beam spot centroid position and radius throughout the first 60 seconds of logging.

Craig Conley and Rick Savage

We rotated the in-vacuum periscope structure, installed the stabilizing slides, slid it down to close to its final location, then installed the center target for final alignment (see attached photo).

We are ready for the final alignment with the help of IAS.  We plan to do this work on Friday.  We have some clean tools staged outside the cleanroom on a clean cart (covered with foil).

Jax, Daniel

We installed the differential frequency difference divider and PLL in R1. It is cabled up but still waiting for power.

The turn on of the ITMX ISI is currently one button.  Please use level 3 on the command page.

The blends are TCrappy on Stage1 all dofs; Stage2 has 100mHz on X & Y, 250mHz elsewhere.  There may be more optimization for Stage2 or maybe not.  As long as the no isolation position and the Target remain close, the one button up should continue.  Otherwise, well you know the drill.

Hats off to Jim & RichM.

Rich, Jim and Hugh

The ETMX BSC-ISI is running a level 2 controller (~25Hz UUG) with low frequency blend filters (~40Mhz stage 1 and ~250mHz on stage 2)

We were to able to turn on the level three controllers mostly due to an excessive amount of 60Hz pick in the GS13s and L4Cs, this needs to get looked

 We still need to finalize the tilt decoupling

I have been hesitating to post this result as I am getting a calculation which doesn't agree with the measurement. (Also this is kind of a side track of the PRMI commissioning)

I did a back of envelope calculation of how large Michelson optical gain we would get at REFLAIR_A_RF45 with PRM misalgined. Currently, I am getting a dubious estimation which is 4 times smaller than what was measured on 31st of January (see alog 9698). I expected it to be 1.7e9 W/m while the measurement claimed 6.8e9 W/m. For those who are insterested in the detail, I am attaching my caculation.

Any suggestion is welcom. As usual, there must be a stupid reason. Thank you.

Andres R. & Jeff B.

    We finished cabling and suspended H1-SR2. The masses appear to be hanging correctly as no BOSEM adjustments were necessary to center the flags. After confirming the 50% light positioning of the BOSEMs, we started the Phase 3A transfer functions.     

- PSL Check done: Watchdogs look good, ref cav is locked but doesn't look clean and the FSS is resonant at 8:55 AM PT but only locked since 7:50 AM PT. Sheila D was notified.

- ACB work in the West Bay

- TMS work at EY

- Electrical inspector on site to meet with Richard M.

- HAM4 SR2 work

Scott, Mark, Mitchell

Today with Apollo's help we were able to suspend the ACB from the solid stack to begin the balancing process. After correcting an assembly error on my part we successfully hung the baffle. For reasons still unknown the baffle is bottomed out with the documented payload added. After removing 5lbs of mass the baffle box was still mostly bottomed out. I am currently in discussions with Mike Vargas and Scott Shankle about this issue.  

I updated all ODC strings, as well as the bitmask and string scripts in cds/h1/scripts:
h1setODCbitmask
h1setODCbitstrings

SVN revision 7038

[Rich Hugh Arnaud]
When activating the ISI level 3 controllers the boost filter of level 2 under FM9 would be enabled (instead of level 3 boost under FM8). This was due to a simple error that we modified from the python script running behind the "isolate" command.

line 350 of script BSCISItool under

/opt/rtcds/userapps/release/isi/common/scripts/

was modified from :

    if ($control_level eq 3) {@commands = ("ALL OFF DECIMATE OUTPUT INPUT FM4 FM5 FM6 ON") x $num_dofs, @boost_commands = ("FM9 ON") x $num_dofs; }

to

    if ($control_level eq 3) {@commands = ("ALL OFF DECIMATE OUTPUT INPUT FM4 FM5 FM6 ON") x $num_dofs, @boost_commands = ("FM8 ON") x $num_dofs; }

the script was comitted under the svn revision 7037

We rencently noticed a rounding issue when saving filter files under foton for the first time. (See SEI aLog # 360)

We needed a brand new foton file, with the filters of an actual platform, to perfom before/after saving in foton comparison.

To do so: I made a backup copy of H1ISIITMY.txt. Then I Emptied the coefficients of H1ISIITMY.txt, after letting Hugh know that no one should reload the coefficients on ITMY while I was doing that. I then ran the SEI prepare script, which copies the coefficients from Matlab files to the Foton file. H1ISIITMY.txt was then the file I needed, I copied its content, and reverted H1ISIITMX.txt to the backup I made earlier.

While doing this, I noticed that, both before and after, the GDS_TP screen of the ISI was notifying a modified IIR file, meaning that the filters in the foton file did not match what was currently being used, and that filters would be updated when pushing the "coeff reload" button. 

I've made some plots of the currently loaded filters on ITMX BSC-ISI

  I used the program plot_current_blend_filters.m from  /ligo/svncommon/SeiSVN/seismic/BSC-ISI/Common/

 which reads the foton file and plots out the filters (thank you Ryan)

  I only plotted out the low pass filters assuming that the high pass filters are appropriately complementary

   A few comments

  A filter name that starts with "T" means that the T240 will be part of the blend

   LP filters that go flat at high frequencies are not recommended, so for instance the Stage 1 X  40mHz and T100mHz N0.44 are bad filters and will get replaced

  The "best"  we have been using the TCrappy filters which are what the blend filters are tuned to

Stage 1 RX  TCrappy == TLLO

  Z = X = Y

  RX = RY = RZ

Everyone


- ITMX motion has been largely reduced by the seismic teem, now the motion at 0.5 Hz is around 0.03 urad, A LOT less than before;

- The tuning of the ETMX is still in progress, but in the meantime Stefan implemented a 'dirty' optical lever feedback which reduced the ETMX PIT motion by about a factor of 5 at 0.5 Hz. With the OL feedback on, ETMX PIT @ 0.5 Hz is around 0.1 urad. There is some gain peaking around 1 Hz.

- In this state, the one arm is stably locked on green with 32 uW (calibration to be confirmed) in transmission (~840 counts in ALS-C-TRX_A_LF_OUT) power fluctuations are small, around 5%. We are not seeing the 01 coming into resonance, so we can make a measurement of the frequency noise red/green. (P.S.: Sheila says that ~800 counts is a good number, corresponding to a good cavity alignment.)

(Sheila, Alexa)

1. We wanted to re-visit the EX PLL shot noise measurement we had previously done.

• From the direct output of the pre-ampifier we measured the beatnote signal to be -33dB at 39.8MHz with 100 Hz BW
• The RF spectrum analyzer had a noise floor of -126dbm with 100 Hz BW (no attenuation)
• From the direct output of the pre-amp with the BBPD blocked, we measured an electronic noise of -118dbm at 100 Hz BW from the PD
• With the fiber blocked we measured noise of -114dBm at 100 Hz BW
• We meaured the power at the BBPD to be 5.8mW with a DC reading of 1.04V --> .52mA at the PD. We calibrated the PD responsivity to be .09 A/W
• To confirm we were measuring shot noise, we increased the optical power by a factor of 2, and saw that the noise with the fiber blocked increased to -111dBm at 100 Hz BW. We expected this increase, so are confident we were measuring shot noise.

2. WIth the EX PLL locked, the arm cavity well aligned, and the green beam flashing, we looked at the PDH error signal out of the demod IMON and measured the peak-to-peak of the signal to be 230mVpp

3. We went on to investigate the fringe wrapping we saw in the PDH amplitude spectrum at the error point. With the arm locked, we only saw a slight difference in the spectrum with the HEPA fans on or off (Sheila will attach pictures). There did not seem to be fringe wrapping, and the acoustic noise seemed minimal. I will look at the PDH shot noise again when I can misalign ITMX and see if the fringe wrapping is still there.. 

Working on ACB with Apollo.

I have been silently checking the signal chain of the REFLAIR and POPAIR RFPDs using the AM laser (a.k.a. PD calibrator) to make sure that they are functional expectedly.

Summary

• REFLAIR_A and POPAIR_A looked good as they showed reasonable signal gains
• On the other hand, REFLAIR_B and POPAIR_B RFPDs showed relatively large discrepancy from the expected values. I might have missed some gain factors somewhere. I will revisit these RFPDs later when I get a chance.

The RF frequency of the AM modulation was adjusted in each measurement such that the demodulated IF signal was below 50 Hz.

Calibration of the amplitude modulation depth

We recalibrated the AM laser.

The current setting of the laser was changed recently because we opened up the current driver when we thought the laser diode had been dead in the early December. Then the laser head and its current driver were sent to Rich at Caltech for his extensive testing although the laser magically fixed itself and he didn't find anything wrong. So this was the first time for us to use the AM laser which had been fixed. Because of that mysterious event, I wanted to recalibrate the laser. First of all, Yuta and I measured the power to be 2 mW with an Ophir Vega without the attenuation filter. Then we measured the modulation depth for the amplitude modulation by using a Newfocus 1611 as a reference.

The new calibration for the amplitude modulation is:

P_am =  5.13 mW x (P_dc / 1 mW) * (1 V / V_drive)

where P_dc is the laser power at DC and V_drive is the drive voltage when it is driven by a 50 Ohm source. For example, if one puts this laser to a PD which then shows a DC laser power of say 2 mW, the AM coefficient is now 5.13 mW x ( 2 mW / 1 mW) /V_drive = 10.26 mW/V_drive.

• Some details for derivation:
  • DC transimpedance of NF1611= 10k Ohm
  • AC transimpedance of NF1611 = 700 Ohm
  • Responsivity of NF1611 at 980 nm = 0.5 A/W
  • Measured DC voltage = 7.36 mV
    • => DC laser power of 7.36 mV / 10kOhm / 0.5 A/W = 1.47 uW
  • Measured AC voltage when driven by 0.5 Vpp at 10 MHz = 1.32 mVpp (measured by a 50 Ohm oscilloscope)
    • => P_am = 1.32 mV / 700 Ohm / 0.5 A/W = 3.771 uW
    • => AM coefficient is 7.54 uW / V_drive
  • Therefore the AM calibration is:
    • 7.54 uW / 1.47 uW x 1 mW = 5.13 mW x (P_dc / 1 mW) * (1 V / V_drive)

REFLAIR_A_RF9 (S1203919)

Remarks:

The signal chain is OK. The PD response is smaller by 15% for some reason.

It seems as if the transimpedance is smaller by 15% than what had been measured at Caltech (LIGO-S1203919). The cable loss from the RFPD to the rack was measured to be 0.47 dB. Be aware that the demod gain is half of the quad I/Q demodulator because this is a dual channel demod (see E1100044). The demod conversion gain is assumed to be 10.9 according to LIGO-F1100004-v4.

• Measured DC at BNC jack = 108 mV
  • DC laser power = 108 mV / 100 Ohm / 0.67 A/W = 1.61 mW
• Expected AM signal when driven by 0.1 Vpp = 5.13 mW x (1.61 mW / 1 mW) x 0.1 Vpp x 0.67 A/W x 245 Ohm = 135.6 mVpp
• Measured AM signal at the SMA jack of the RFPD enclosure = 115 mVpp
  • This is already smaller by 15%.
  • If we blame the transimpedance, it must be 208 Ohm rather than 245 Ohm.
• Measured AM signal at the rack = 109 mVpp
  • cable loss = 0.47 dB
• Expected IF signal = 135.6 mVpp x 10.9 / 2. = 622 mVpp
• Measured IF signal = 570 mVpp
  • If we take the 15% and 0.47 dB losses into account, we would expect this to be 527 mVpp.
• Expected ADC counts = 135.6 mVpp x 10.9 x 2^16 counts /40 V x 1/2 = 1209 counts pp
• Measured ADC counts = 900 counts pp
  • If we take the 15% and 0.47 dB losses into account, we would expect this to be 973 counts pp.
  • This is within 10% divation. Good enough.

REFLAIR_A_RF45 (S1203919)

Remarks:

The signal chain is healthy.

Found cable loss of about 1.5 dB. The measurements excellently agree with the loss-included expectation.

• DC laser power = 1.61 mW (the same as REFLAIR_A_RF9)
• Expected AM signal when driven by 0.1 Vpp = 5.13 mW x (1.61 mW / 1 mW) x 0.1 Vpp x 0.67 A/W x 341 Ohm = 188.7 mVpp
• Measured AM signal at the SMA jack of the RFPD enclosure = 190 mVpp
  • Very good agreement !
• Measured AM signal at the rack = 160 mVpp
  • Corresponds to loss of 1.5 dB
• Expected IF signal = 188.7 mVpp x 10.9 = 1028 mVpp
  • If the loss is taken into account, it is going to be 1028 mVpp x -1.5 dB = 865 mVpp
• Measured IF signal = 880 mVpp
  • Consistent with the loss-included expectation
• Expected ADC counts =1028 mVpp x 2^16/40 x 2 = 3369 counts pp
  • If the loss is taken into account, it should be 3368. x -1.5 dB = 2837 counts pp
• Measured ADC counts = 2784 counts pp
  • Good agreement with the loss-included model

POPAIR_A_RF9 (S1300521)

Remarks:

The signal chain is healthy.

The measurement suggests that there is loss of 1 dB somewhere. I didn't measure the cable loss this time.

• Measured DC at the BNC jack = 95.6 mV
• Estimated DC laser power = 95.6 mV / 100 Ohm / 0.67 A/W = 1.42 mW
• Expected AM signal = 5.13 mW x (1.42 mW / 1 mW) x  0.1 Vpp x 0.67 A/W x 741 Ohm = 361.7 mVpp
• Expected ADC counts = 361.7 mVpp x 10.9 x 2^16/40 counts/V = 6454 counts pp
• Measured ADC counts = 5705 counts pp
  • If we assume this discrepancy is from a loss, it corresponds to loss of 1.07 dB.

POPAIR_A_RF45 (S1300521)

Remarks:

The signal chain is OK. Though loss sounds a bit too high.

The measurement suggests a possible loss of 2.6 dB somewhere. I didn't measure the cable loss.

• Estimated DC laser power = 1.42 mW
• Expected AM signal = 5.13 mW x (1.42 mW / 1 mW) x 0.1 Vpp x 0.67 A/W x 837 Ohm = 408.5 mVpp
• Expected ADC counts = 408.5 mW x 10.9 x 2^16/40 counts/V = 7295 counts pp
• Measured ADC counts = 5391 counts pp
  • If the discrepancy is assumed to be from loss somewhere, the loss should be 2.6 dB.

REFLAIR_B_RF27 (S1200234)

Remarks:

The signal gain is bigger than the expectation by a factor of 2.3.

• Measured DC at the BNC jack = 836 mV
  • This corresponds to a laser power of 836 mV / 2000 Ohm / 0.4 A/W = 1.045 mW
• Expected AM signal = 5.13 mW x (1.045 mW / 1 mW) x 0.05 V_drivepp x 0.4 x 1000 Ohm = 107.2 mVpp
• Expected ADC counts = 18 dB x 107.2 mVpp x 10.9 x 2^16/40 counts/V = 15206 counts pp
  • I assumed that the gain factor of the diplexer (LIGO-D1300989) to be 18 dB at 27 MHz.
• Measured ADC counts = 35431 counts pp
  • This is bigger than the expected by a factor of 2.3

REFLAIR_B_RF135 (S1200234)

Remarks:

The signal gain is bigger than the expectation by a factor of 1.5

• Measured DC laser power = 1.045 mW
• Expected AM signal = 5.13 mW x (1.045 mW / 1 mW) x 0.0014 Vdrivepp x 0.4 A/W x 1000 Ohm = 3 mVpp
• Expected ADC counts = 43 dB x 3 mVpp x 10.9 x 2^16/40 counts/V = 7573 counts pp
• Measured ADC counts = 11689 counts pp
  • This is bigger than the expected by a factor of 1.54

POPAIR_B_RF18 (S1200236)

Remarks:

The signal gain is bigger than the expectation by a factor of 2.3

• Measured DC at the BNC jack = 744 mV
• DC laser power = 744 mW / 2000 Ohm / 0.4 A/W = 0.93 mW
• Estimated AM signal = 5.13 mW x (0.93 mW / 1 mW) x 0.1 Vdrivepp x 0.4 A/W x 1000 Ohm = 191 mVpp
• Estimated ADC counts = 191 mVpp x 10.9 x 2^16/40 counts/V = 3404 counts pp
• Measured ADC counts = 7803 counts pp
  • This is bigger than the expected by a factor of 2.3

POPAIR_B_RF90 (S1200236)

Remarks:

The signal gain matches with the expected value, but I don't believe this.

• DC laser power = 0.93 mW
• Estimated AM signal = 5.13 mW x (0.93 mW / 1 mW) x 0.1 Vppdrive x 0.4 A/W x 1000 Ohm = 191 mVpp
• Estimated ADC counts = 191 mVpp x 10.9 x 2^16/40 counts/V = 3408 counts pp
• Measured ADC counts = 3549 counts pp
  • This suspiciousely shows an excellent agreement with the expected one.