During the reboots I took the opportunity to have another look into the OAT RefCav in the optics lab.

I removed the 50/50 beam pslitter infront of the RF LSC diode, so now ~30 mW of power is incident. In addition in optimised the HWP infront of the PM to reduce the AM, 2f_sb = < -80dB.

The few irises in the beam path are closed down, I looked with the viewer and reduced the iris so it was just not clipping.

I didn't find a low enough ND filter to o the paracitic interfernce hunt.

The cavity locks stable with a UGF ~300kHz, the settings are

The Laser temperature on the controller displays: T+40.991, the slow output (T-ed to the laser slow input and the oscilloscope) is at -620 mV.

Once we get the cavity locked again we can see if we gained anything.

I put the boost filters back in FM10 of the ISO filter bank on BSC6 and BSC8. They switch when crossing zero but I have changed the tolerance (300 to 50 counts) and the time out (2s to 20s).

Elli and Bram

We went to the EY and injected a sine wave at 2280 Hz, 200 mVpp into the CMB-B (PDH), Exc A input. Then we used ddt to measure the tranfer coefficients of the SegX_Ix/SegX_Qx. We optimised the demodulation phase and maximised the transfer coeeficient. Although we could not zero the Q-phase, we got a factor of ~30x between the I and Q phase for all segments in both WFS-A and WFS-B.

in between the measurements we aligned the beams onto the WFS but adjusting the picomotor mounts. We actually did this manual and did NOT use the picomotor driver, which would be nice in the future ...

Now we can use the WFS for alignment feedback to the Quads, well at least measure the TFs.

Attached are plots of dust counts > .5 microns in particles per cubic foot.

I attached 5 grounding plugs to the ITMY coil drivers Test Input this afternoon ~ 4:30 pm.  Three were connected at the top stage driver, and one each for UIM and PUM drivers.  I plan on doing the same for ETMY tomorrow before making measurements of the coil driver noise.

(Betsy, Travis, Deepak, Cheryl, Dale on the camera)

All the prep work paid off and the MC2 was installed into the chamber relatively easy this afternoon.  Using the genie, we hoisted it up to the elevator which was attached to the arm, attached the spacer to the bottom of the suspesnion, and then used the arm to swing it into place on the ISI table against the cookie cutter.  We added a few dog clamps to make sure it doesn't walk away overnight.  Tomorrow we continue adding dog clamps, hooking up cables, etc.

Report of site activities:

• Betsy B. Corey G. and others in to the LVEA to move cleanrooms.
• Cleaning crew Christina C. and Karen R. to LVEA to clean HAM03 per WP#3378.
• Corey G. to the LVEA, to do HAM03 accounting of weights.
• Kyle R. and Apollo crew  to the LVEA, H1 output tube to torque GNB flanges.
• Apollo crew to the LVEA, surveying.
• Patrick T. to the LVEA, check dust monitors around HAM03 area.
• Filiberto C. to the LVEA, add some electronics for TCS ring heater.
• Dale I. to the LVEA, film activities around HAM03.
• Hugo and Mitchel to the LVEA, to do inventory of cables around HAM03.
• Jodi F. to Y-End and LVEA, take photos.

During the past few weeks I have been working on calibrating the sensor readouts from the Quad Suspension OSEMs on all four stages: main chain top M0, reaction chain top R0, upper intermediate mass (L1 stage or UIM), and penultimate mass (L2 stage or PUM).  One way to check the OSEM readouts is to measure their response to an excitation of the top mass, and then compare this to the response predicted by the 20120601TMproductionTMrehang mathematical model.  The Quad Suspension has a 0.43 Hertz mostly "Longitudinal" mode, and exciting this mode by shaking the main chain top mass will result in peaks at 0.43 Hz for all OSEM sensor spectra (M0F1 spectrum attached as an example).  Comparing the peak height data of each OSEM at 0.43 Hz to the data predicted by the model should show any dissimilarity between the predicted behavior of the OSEM sensors and what is actually seen.  

The file OSEMsensorplot.pdf shows the magnitude of the OSEM sensor readouts (vertical axis) for each OSEM ID(horizontal axis) scaled so that the magnitude of the Main Chain F1 OSEM is always one.  I tried a few different methods of measuring the power spectra that generate this plot, and they are labeled on the side of each plot.  In each case damping of the top stage reaction and main chains was OFF.

The model prediction is the sensor response at the 0.43 Hz peak for each OSEM derived from the mathematical model of the quadruple suspension.  The measurements labeled "White Noise" are from excitations of white noise into all Main Chain TOP degrees of freedom (Longitudinal, Transverse, Vertical, Roll, Pitch, and Yaw).  These white noise power spectra were collected WHILE the excitation was being performed.  In the 7/3/2012 White Noise measurement the coherence in the L2 stage OSEMs was terrible, and so these data points are not reliable.  The measurements labeled "Offset" are derived from an excitation where each main chain TOP degree of freedom was displaced with a static offset value after a turn-on ramp time of 10 seconds, then this static offset was instantly changed to zero to let the suspension swing freely.  Lastly the measurements labeled "Sine Relax" were taken by exciting the main chain TOP mass Longitudinal DOF with a 0.43 Hz sine wave drive for about five minutes, then the drive was turned off and the suspension allowed to swing freely for about 2 minutes before the power spectra were taken.

The sensor plot shows that the different measurement approaches lead to consistent OSEM data, but we see immediately that the lower stages have some problems.  The L1 stage magnitudes on each suspension appear slightly lower than predicted, but only ITMY OSEM L1LL is way off.  This could be a problem with the L1LL alignment or an electronic issue that fails to correctly communicate the position of the flag on that sensor.

The L2 stage is troubled with multiple symptoms, each OSEM is well below the model prediction.  I am still struggling to understand why the response is so small.  One glaring problem is that the L2UR sensors on both ETMY and ITMY are practically zero compared to the other L2 OSEMs.  I suspect that these specific sensors dead or barely working, but will need to check this somehow.

I replaced the H2GDSAWGL0 model with H2TCSITMY on h2tcsl0 following the install of a second ADC card in this front end. The front end now has 2 ADC and 1 DAC cards. PEM uses the first ADC, TCS uses the second ADC and the DAC card.

The H2 DAQ was restarted with the new configuration.

The h2tcsl0 restart invalidated all the front end data. After the DAQ restart I had to restart the data streamers on each model, so the H2 data gap was longer than anticipated at about 10 minutes.

To measure the Spring Profile one must use a plunge micrometer and then measure the distance from the top of the Optics Table down to the Spring.  For each Spring there are two access points/thru-holes for the micrometer:  at the Spring Tip & at the Spring Base (I forgot to measure the Spring Base measurement when I did this last Wed, so I re-did the measurement this morning)

HAM3 Spring Profiles

Spring 1 (where tip location warrants corner location, in other words Spring1 is mounted on Spring Post which has Corner 3 Actuator & CPS, but Tip is in Corner1 zone)
base:  0.388"
tip:  0.375"

Spring 2
base:  0.399"
tip:  0.381"

Spring 3
base:  0.390"
tip:  0.378"

These measurements were made with our clean plunge micrometer.  It was fitted with a 2" extension.  Measurements are +/- 0.0005" (this is the slop of the locked Lockers).  I also made Tip measurements where I avoided the Spring Hatches---just stayed on the Optics Table.

On July 31st Unit #6 was placed into a storage container. Aug. 1st a purge was started at 10:30am. Ambient air was 8.2 tdºC at 24.7ºC. Boil-off LN2 was run at 20lpm until about Aug. 3rd 2:00pm.

I tried to dry out the bag the wand was in and get a baseline for the purge gas, but after approximately 15 minutes of purging just the ameristat bag and the dewpoint wand was reading -34.4tdºC and 25.5ºC. I must have been picking up a fair bit of moisture from the line and bag.

Interestingly Unit 6 in the storage container dropped in dew point much faster than HAM6 in a shipping container. Maybe there is a significant difference between the shipping and storage containers. Do the inflow and outflow locations for the purge make a difference? Less surface area in a storage container?

Found that the daqd process had quit on h2nds0.  Last error message in the log file:

Invalid broadcast received; seq=3177250 tp_seq=3177267 gps=1028180001 tp_gps=1028180002 gps_n=62500000 tp_gps_n=187500000

Restarted daqd process.

If a user is in the middle of uploading files (or even just getting started), and he forgets to select a file for uploading and subsequently hits "UPLOAD FILE" with nothing selected, it takes the user to a blank white screen. Thankfully, nothing is lost, and one can just hit his browser's back button, but the log should throw a warning / error when this situation arises. A pop-up that gray's out the log, saying "You've not selected anything to attach, please browse for a file" with an "OK" acknowledge button would suffice. Or if that's too sophisticated for the infrastructure of the log, this user error should at least take you to another page with the same warning, and a link back to the upload page and/or the add report page. 

One of the nice features of commercial search engines is that surrounding a phrase with double quotes forces the search to use the whole phrase as an exact string, i.e. "Optical Lever" returns only results that contain the whole phrase, not every entry with either "optical" or "lever." Is it possible to do this with our aLOGs?

In my bouncing between aLOGs, I've found that the colors for different Sections + Tasks are not symmetric between them. Any chance we could? (I'd specifically notices that the LogBook Admin Sections are RED in the LHO aLOG, and SEA GREEN in the LLO aLOG).

When writing a comment to an aLOG, the user has the option to change the title (as opposed to the default "Comment to [insert original subject here]"), or change the Section / Task. However, after submitting the entry, these additions / edits are not reflected on the resulting comment. Interestingly enough, the information is stored, however, because when one clicks to edit the comment, the changes and new title are still there.

See, for example, LHO aLOG 3727, LHO aLOG 3550, or LLO aLOG 4156.

The attached are the Euler and OSEM-basis spectra for the H1 PR2 M1-stage OSEMs. Each plot contains traces when M1 Damping was on and off from the nights of 08-01-2012 and 08-02-2012.   

J. Kissel, T. Vo

After finally getting the optical levers aligned while the optics were aligned in a good state for the cavity, I've taken a spectra of both H2 SUS ITMY and H2 SUS ETMY in the quiet time mentioned in the isolationist data miner's dream. 

There're lots of fun features, differences, and similarities between the two test mass spectra, that will be good to noodle over. This will be excellent material to try to reproduce via models!


If anyone wants to gather future data, this calibrated template lives here:
/ligo/svncommon/SusSVN/sus/trunk/QUAD/Common/Data/2012-07-27_H2OAT_Oplev_ASDs.xml

Jeff K. , Thomas V.

Below are the calibration parameters for the H2 ITMY Optical Lever:
        Slope          Y-intercept
Pitch [ 580.41229822  -11.51774017]
Yaw  [ 689.70532274  -13.3345144 ]


And here are the calibration parameters for the H2 ETMY Optical Lever:
         Slope           Y-intercept 
Pitch [ 1666.80728788   -33.14694715]
Yaw  [ 1727.67131855     23.41350328]

Both sets of calibrations were attained via the same process of moving the QPD along a translation stage and measuring the output signal.  All four sets of slopes are in units of radian*meters.