J. Kissel, K. Venkateswara, E. Shaw

We've processed the 1 [mHz] excitation data taken over night, and it confirms our preliminary results from yesterday that the center of mass of the beam is d = 20 [um] above the suspension point. Indeed, because we shielded most of the open end of the thermal box with Ameri-stat (as shown in yesterday's pictures), the insturment's noise floor was much better. 

Note, we've also switched from Krishna's sine-wave fitting code to just grabbing the excitation amplitude from the ASD, and obtaining a transfer function value from there,
peak amplitude [rad_{pk}] = ASD [rad_{rms}/rtHz] * sqrt(binWidth) [rtHz] * sqrt(2) [pk / rms].
Since we know the response to ground tilt should tend to unity at high frequency, as any inertial sensor, and we've not changed the excitation amplitude, the collection of peak amplitudes are normalized by the highest-frequency amplitude to obtain the (beam / ground) [rad/rad] tilt transfer function. We lose a quantitative estimate of the uncertainty with this method, but we gain simplicity/clarity and it's reasonable to say from the SNR that the estimates are good to at least 20%, if not better. See attachment. 

The adjustment masses are a distance D = ~3 [in] above the C.o.M., so the change in (d = C.o.M. w.r.t the Susp. Point) per gram of adjustment weight, dm, is

dC.o.M.    D     3.0 [in]   76.2e-3 [m]
------  = --- =  -------- = ----------- = 18.1 [um/g]
  dm       M     4.2 [kg]     4.2  [kg]

As such to achieve a minimal separation, Krishna and Eric spent the rest of the morning/early afternoon removing 1.1+/- 0.05 [g]  of mass (equal to a 19.91 [um] shift in C.o.M. down toward the Susp. Point). A separation of ~1 [um] means the rejection of horizontal acceleration is

d * M_{bar}    1e-6 [m] * 4.2 [kg]        
----------  =  -------------------- = 7e-6 [rad/m]
  I_{bar}          0.59 kg.m^2

... pretty awesome! After rebalancing, they sealed the vacuum chamber (tool tight), confirmed that the new resonant frequency is 8.8 [mHz] as expected, and headed home for Seattle. 

When Krishna returns on Monday, we'll start pulling vacuum on the tank which should take about a day. From there we tweak the balance of the beam to remain within range of the autocollimator, re-measure the C.o.M.-Sus.Point separation to confirm the awesome acceleration rejection, and begin the process of connecting the system to the aLIGO DAQ.

I checked the difference in position of the Imx mirrors before and after the chamber was pumped.

I used the vacuum pressure sensor channel (HVE-LY:Y1_120BTORR) to find the times were the pumped was performed.
Then, to check the difference in position I used the times:
Before: 	2014/08/05 09:00:00 UTC
After: 	2014/08/07 10:00:00 UTC

The table shows the count difference (before and after the pump):

Difference			
        L (counts)	P (counts)	Y (counts)
IM1	10	                7.42	         -7.76
IM2	-5	               -10.6	           38.8
IM3	-27	              -21.2	           9.7
IM4	4	                31.8	           38.8

The DAC is 18 bit , which gives us a maximum of +- 131072 counts (2^18 /2 = 262144/2) in OSEMS basis (UL, LL, UR, LR).
Right now, the maximum number of used counts is 116600 (H1:FEC-104_DAC_OUTPUT_0_5), which give us a free range of 14472 more.

	UL	        LL	         UR	        LR
IM1	133.0	5.4	         -0.4	        -128.0
IM2	-425.8	-243.6	241.1	423.3
IM3	-272.3	92.1	        -105.6	258.8
IM4	-59.2	-605.7	607.7	61.2

To recover the position had it before the pump, we need a maximum of 425.8 counts.
The next table shows, in counts, how much is needed to recover the original position.
 
I am attaching the spreadsheet used for the calculations and the times series plots.

[Alexa, Kiwamu, Koji]

We found that IMC WFS B had quite small error signals. We tracked down this to be too small LO.
What we found was the LO cable had bad connection at the SMA connector. This is the same problem as Kiwamu reported before.

After recrimping the IMC WFS B cable, the all of the cables on ISC-R2 rack was reviewed.
All of the cables had the same crimping issue. Also, most of the SMA were not secured.

All of the SMA cables were recrimped and 4~5 SMAs have been replaced.

Here is the list of the LO powers in the monitor. WFS REFL45 has CH1 and CH2 with +13dBm LO power
while CH3/4 indicates very low numbers. In fact these nubers (and the corresponding RF power mons)
are not changing at all. So this could be a DAQ related problem.

=== Rack ISC-R1 U07 ===
H1:IMC-WFS_A_DEMOD_LOMONCHANNEL_1 = 16.0804
H1:IMC-WFS_A_DEMOD_LOMONCHANNEL_2 = 15.9532
H1:IMC-WFS_A_DEMOD_LOMONCHANNEL_3 = 15.999
H1:IMC-WFS_A_DEMOD_LOMONCHANNEL_4 = 16.5534
=== Rack ISC-R1 U05 ===
H1:IMC-WFS_B_DEMOD_LOMONCHANNEL_1 = 16.1007
H1:IMC-WFS_B_DEMOD_LOMONCHANNEL_2 = 16.1821
H1:IMC-WFS_B_DEMOD_LOMONCHANNEL_3 = 16.1618
H1:IMC-WFS_B_DEMOD_LOMONCHANNEL_4 = 16.3296
=== Rack ISC-R2 U38 ===
H1:ISC-RF_C_REFLAMP45M_OUTPUTMON = 17.5009
=== Rack ISC-R2 U37 ===
H1:ISC-RF_C_REFLAMP9M1_OUTPUTMON = 20.2811
=== Rack ISC-R2 U34 ===
H1:LSC-REFLAIR_A_RF9_DEMOD_LOMON = 20.6277
H1:LSC-REFL_A_RF9_DEMOD_LOMON = 20.9278
=== Rack ISC-R2 U30 ===
H1:LSC-POPAIR_A_RF9_DEMOD_LOMON = 23.059
H1:LSC-POPAIR_A_RF45_DEMOD_LOMON = 19.8342
H1:LSC-REFLAIR_A_RF9_DEMOD_LOMON = 20.6073
H1:LSC-REFLAIR_A_RF45_DEMOD_LOMON = 19.8494
=== Rack ISC-R2 U28 ===
H1:LSC-POPAIR_B_RF18_DEMOD_LOMON = 22.5656
H1:LSC-POPAIR_B_RF90_DEMOD_LOMON = 20.1851
H1:LSC-REFLAIR_B_RF27_DEMOD_LOMON = 23.0234
H1:LSC-REFLAIR_B_RF135_DEMOD_LOMON = 18.0488
=== Rack ISC-R2 U24 ===
H1:LSC-POP_A_RF9_DEMOD_LOMON = 23.3642
H1:LSC-POP_A_RF45_DEMOD_LOMON = 19.8494
H1:LSC-REFL_A_RF9_DEMOD_LOMON = 20.9328
H1:LSC-REFL_A_RF45_DEMOD_LOMON = 20.119
=== Rack ISC-R2 U18 ===
H1:ASC-REFL_A_RF9_DEMOD_LOMONCHANNEL_1 = 17.174
H1:ASC-REFL_A_RF9_DEMOD_LOMONCHANNEL_2 = 17.0824
H1:ASC-REFL_A_RF9_DEMOD_LOMONCHANNEL_3 = 16.94
H1:ASC-REFL_A_RF9_DEMOD_LOMONCHANNEL_4 = 17.3011
=== Rack ISC-R2 U16 ===
H1:ASC-REFL_A_RF45_DEMOD_LOMONCHANNEL_1 = 13.3693
H1:ASC-REFL_A_RF45_DEMOD_LOMONCHANNEL_2 = 13.471
H1:ASC-REFL_A_RF45_DEMOD_LOMONCHANNEL_3 = -75.0432
H1:ASC-REFL_A_RF45_DEMOD_LOMONCHANNEL_4 = -74.9568
=== Rack ISC-R2 U10 ===
H1:ASC-REFL_B_RF9_DEMOD_LOMONCHANNEL_1 = 17.3215
H1:ASC-REFL_B_RF9_DEMOD_LOMONCHANNEL_2 = 17.2604
H1:ASC-REFL_B_RF9_DEMOD_LOMONCHANNEL_3 = 17.2096
H1:ASC-REFL_B_RF9_DEMOD_LOMONCHANNEL_4 = 17.3011
=== Rack ISC-R2 U08 ===
H1:ASC-REFL_B_RF45_DEMOD_LOMONCHANNEL_1 = 13.5117
H1:ASC-REFL_B_RF45_DEMOD_LOMONCHANNEL_2 = 13.1913
H1:ASC-REFL_B_RF45_DEMOD_LOMONCHANNEL_3 = 13.3642
H1:ASC-REFL_B_RF45_DEMOD_LOMONCHANNEL_4 = 13.4558
 

BSC9 annulus not pumping yet -> Problem with aux. pump cart

Gerardo already pumping BSC1 and HAM3 -> will continues leak hunting on Monday

There seems to be some slow oscillating taking the outputs to higher values (1000+.) unlike the ITMX, it doesn't seem to go out of control bt the larger values are still worrysome to me.

I'll move it to isolated damped for the weekend.

Took a couple of photos of ETMY after Rai's discharging work was completed.  As with yesterday's pictures, it's tough to tell if there's any dust on the surfaces or not.

Tried focus stacking for image ETMY2.jpg in order to improve the depth of field.  Didn't seem any better than simply shooting with a smaller aperture.

All images are quite large, so there's no preview available.

RichardM, PeterK

I may not get to fixing this tonight so I at least wanted to report it.

I think Stage1 Isolation is ok but when Stage2 is Isolated, it looks like it rings up exciting stage1 and both tripping on Actuators.  HEPI is not tripping.

Currently, ITMX is under managed guardian at Isolated_Damped.

12:15 Fred et al out of LVEA
13:00 Doug, Jason done at ITMY
13:15 Gerardo to LVEA looking for pump cart, pump HAM4 annulus
13:30 Karen to EY
13:30 RichardM to EY to verify an interlock is working, back to 14:30
14:00 GregG turning on CO2 laser in squeezer bay
14:15 Fil, Manny to EX for ISC WFS cabling
15:00 Jason to BS oplev, done 15:15
16:00 Pablo to EX to work on VCO characterization

Start time 11:00 am.

Pressure as of 1:46 pm 2.0 x 10^-5 torr at the aux cart.

Start time was 10:30 am.

Current pressure as of 1:45 pm 1.3 x 10^-5 torr.

Morning Shift Notes
916  - Nathan beginning work in the OSB laser lab
920 - Rai to EX to work on experimental setup
929 - Gerardo moving pump cart from GV-5 to BSC1 for annulus pumping
945 - Kyle verifying picomotors off at EX, preparing to begin pumping
1004 - Kiwamu, Alexa doing projection work at HAM2 (WP 4782)
1008 - Fil and Manny working on cabling at EX
1129 - Bubba craning pelican case with test mass from West Bay to High Bay
1129 - Fred with small tour in LVEA
1202 - Projection work on IMC complete for now

Found cdswiki to be locked up and dead, console showed no display.  Rebooted.

• ETMy Ionization Test:  Would like to run another decharging measurement.  Whole operation could be streamlined to a day
• LVEA Laser HAZARD currently
• Oplev work:  itmy oplev laser fiber damaged.  also found damaged qpd.  Working on organizing oplev hardware.
• Kiwamu:  IMC work will continue this morning (probably will keep Laser HAZARD)
• Sorry state of Power Meters brought up
• Pump EX, work with Rai at EY, start pumping annuli at LVEA
• electrometer ITM measurements in West Bay continue
• Testing of SEI controllers
• EX:  Rotation Sensor measurement work continues (mainly balancing where roughing pump won't matter)
• Visitors:  Tim McDonald

With the closing of most of the chambers recently, we are in a state where we can relieve Alarm Levels on some Dust Monitors (note:  HAM6 is still open & we have exposed parts in the West Bay Test Stand area).  At any rate, I went through Dust Monitors 1, 2, & 3 & raised their alarm levels (on the order of 10^2 counts for 0.3 & 0.5um).  Could do this for other Dust Monitors which are away from clean hardware.

I notified Jeff Bartlett about this.  Will chat with Calum about whether we want to establish long term values for these levels when we are all buttoned up.

Took a quick look at the FSS MEDM screen and noticed that the RFPD DC value was fluctuating wildly.
Pulled up the filter for this channel and saw that the 2 Hz low-pass filter was not engaged and that
the gain value was set to 1.000.

The 2 Hz low pass filter is now engaged, as it should be, and the gain value was set to 0.150 which
gives readings consistent with those obtained with a digital multimeter plugged into the DC output of
the RFPD.

no restarts reported

Alexa, Dan, Koji, Sheila, Stefan, Kiwamu,

Today we spent some more time on alignment of the IMC with the use of the WFSs loops. After some struggling, we eventually could close all the loops stably. However, the ASC loops tend to drift on a time scale of 30 min.

In parallel to it, we made a first attempt of the ring down measurement. The data did not make sense this time. Ongoing.

IMC alignment:

Our original hope was that once the WFSs were centered, they should be able to servo the IMC to a good alignment. However, it turned out that stably engaging the ASC loops were very difficult for some reason. The first issue we noticed was that the MC2 trans QPD did not show a reasonable signal. It looked all noise and indeed changing the whitening settings did not change the shape of the noise. This indicated some issues in the analog circuits. Stefan and Sheila went to the rack and found that a number of cables were unplugged. Also, they found that the whitening electronics were turned off. So they plugged the cables back to the whitening box and powered up the whitening box. This recovered signals on the MC2 trans QPD. This then allowed us to close the 'DOF3' loop which is the centering servo for the MC2 QPD.

However, we were still having a difficulty in closing the rest of two loops in the IMC ASC. They use the signals derived from the WFSs. The symptom is that the error signal looked too big even though the loops are closed. It looked as if the loop is not suppressing the signals. Acutually, keep running the ASC loops made the power buildup and visibility worse on a time scale of 30 sec or so. We made sure that the dark offsets were successfully removed and centering on these WFSs were fine. But, no success.

After people left, I did some more investigation on the ASC loops. Since I did not like the beam shape in the reflection camera, I went to the table and checked out the beam. I found that there was a ghost beam not being dumped and going into the WFSs. I narrowed the aparture of the iris that was infront of the REFL RFPD such that it catches the ghost beam. Then I digitally removed the dark offset from all the WFS segments and tried closing the ASC loops again. The loops stayed stable for approximately 10 min. However then it started degrading. See the attached. I am not sure why, but I am worried about RFAM. I am leaving the ASC loops running for the night to see the long term stability.

Ring down measurements:

We also spent some time trying to measure the cavity decay time (storage time) in order to estimate losses in the cavity. We tried various ways of shutting the control or light off, but ended up with switching the polarity of the fast signal in the IMC board. This is the same technique as Livingston did recently (LLO 13748).  We were expecting to see something like 17 usec 1/e decay time, but the measurement tended to give us about 35 usec which is twice bigger than the expectation. At this point, it is unclear why the decay time is such long. The attached is a picture of the raw data displaced on an oscilloscope. The PD is Thorlabs, PDA100A on the IOT2L table. The bandwidh is 2.4 MHz according to the data sheet which should be fast enough for this measurement.

It maybe independent, but we know that this transmitted light is largely clipped (seemingly more than 20% of its total intensity) somewhere in chamber before it comes out to the IOT2L table. So we are interested in repeating this measurement at a different port. Maybe at REFL or IOT2R. The measurement is therefore ongoing.