(Sheila, Daniel)
This afternoon the noise eater of the ALS laser in H1 EX was oscillating. After some TwinCAT work, we were able to toggle the noise eater off and on remotely. This worked as expected and cleared the noise eater oscillation.
PS. There are 2 relay contacts wired up. Only the first one seems to be needed. I disconnected the second.
With the RF doubler for the 79.2 MHz source moved on top of the ALS distribution chassis, we took another look at the modecleaner error signal. The intermodulation product with the PSL VCO is still visible but small. It is about an order of magnitude smaller than before. This seems good enough for now, but could potential effect the noise of the full interferometer.
- Craig C. and Rick S. going to H2 PSL Enclosure for PCAL work. 8:50 AM PT - Jeff B to EY to install dust monitor. 9:25 AM PT - Aaron S to EY to do cabling check-off. 9:30 AM PT - Hugh to EY to work on SEI. 9:43 AM PT - Instrument air alarm, Kyle fixed this. - Corey at EY to take off payload. 9:45 AM PT - Filaberto running cables from beer garden to X and Y manifolds. - Jim B, Cyrus R, Dan M trouble shooting instability with frame writer 1, won't bother anyone else. - /ligo server froze, crashing all of the work stations. ~11:35 AM PT - Mitchell in LVEA 2:14 PM PT - Gerardo in LVEA and EY throughout the day. - Arnaud starting a pitch measurement on ITMY. 3:16 PM PT
It seem like the sensor correction on ETMX is good. Several times H1:ISI-ETMX_ST2_SENSCOR_X_MATCH_GAIN has been reset to 0, I'm not sure what does this but maybe it is in the safe.snap or in one of the scripts.
My question for SEI people is:
is there a correct time to turn this on durring the ISI turn on process? Can we leave it on all the time? Can we have turning it on be automated?
Yuta, Stefan, Kiwamu
Our goal in this morning was to get the PRMI locked with the 3f signals and test the stability. However we didn't get there yet.
A good news is that the initial dither alignment worked well, so that the alignment became less painful. Once PRX and PRY were aligned by the dither system, we could get a decent alignment in PRMI.
What we did in this morning:
Before starting measuring Pitch to Pitch on ITMY, I realized the oplev signal was oscillating at high frequencies. I took a spectra and compared with other oplevs, and the noise floor from 1000Hz is ~2 orders of magnitude higher compared to ITMX. Thomas pointed out that this oplev doesn't have an analog whitening filter yet, so we should double check when it will be installed.
dtt template was saved under SusSVN/sus/trunk/QUAD/H1/ITMY/SAGL2/Data/2014-02-28_Oplev_Spectra.xml
What I meant by "oscillating at higher frequencies" is that the noise is higher for ITMY than ETMX as we can see on the time plots (ETMX in green, ITMY in red)
Evan, Yuta
We redid the Michelson noise budget using the NB simulink tool.
The data we used was taken from the long strech MICH lock on Feb 17 (see alog #10127).
The noise budget agrees well with we have done by hand (see alog #10221, #10217).
NB model works pretty nicely.
[Result]
NB_MICH_1076736130.png: Michelson noise budget plot. "Measured" curve shows the sensitivity curve calibrated from H1:LSC-MICH_OUT. Seismic noise is copied from LLO measurement, so seismic noise curve is not real.
sensorNB_MICH_1076736130.png: Noise budget for sensor noises. Low frequency noise mainly comes from the demodulator board noise. Compared with the one we did by hand (alog #10221), there is a factor of 5 difference in ADC noise. This is because we forget to put the PD filter bank gain (H1:LSC-REFLAIR_A_RF45_(I|Q)_GAIN) in the previous one.
[Note on NbNoiseSink]
If you put NbNoiseSink block into your model, noise at the sink will be calibrated by taking out the model loop gain. If you specify a DAQ channel to that sink and if you run 'nbAcquireData' function, it gets the actual data from a NDS server (using Matlab "get_data" function). So, NB tool automatically calculates the sensitivity curve for given GPS time.
Also, note that LiveParts and data fetching fail if you specify GPS time more than ~7 days ago. I'm not sure why, but it is a limitation from "get_data" function.
H1fw1 and the LDAS gateway were rebooted at 14:42 PST to correct problems with keeping the frame writer process running. On examination of the LDAS gateway for frame writer 0, it was determined that significant problems existed that required a reboot of that as well. This interrupted the h1nds0 NDS server and the h1dmt data stream.
Stefan, Kiwamu,
We could not close the oplev damping loops today. It turned out that the oplev servo gains had been wrong since the model reboot on the last Tuesday. In fact, the signs were wrong in safe.snap file. We updated the safe file. Now they are 0.03 and -0.03 for pitch and yaw loops respectively.
The attached is the open loop transfer function with the WRONG sign (i.e. OLDAMP_P_GAIN = -0.03 ) in pitch
After the BSC-ISI passed a coarse alignment check, went out to work on Post-Cartridge tasks for the TMS. Basically we want to remove excess mass from the TMS & get it ready for fine balancing of the ISI.
Restraint Tooling/Table Cover Removed & TMS Upper Mass Released
Went ahead and removed the TMS Restraint Tooling (turnbuckles, chains, & eyebolts). Then I went upstairs and released the Upper Mass. I then removed the Metal Table Cover. Some thing I missed were some questionable eyebolts attached to the Upper Structure. We we want to know whether these eyebolts (most likely) & an aluminum part (not sure) stay on the structure or get pulled off. Will probably have to address this on Monday BEFORE fine ISI balancing.
Safety Stop Structure (Disassembled & Assembled) & Installed
I then went about installing the Safety Stop Structure (D1001781) to the BSC10. First thing I noticed was this assembly was built for H2! (see photo #1) So I had to take the assembly apart and then rebuild it for H1. I then attached it to the ribbing of the BSC chamber. After some manhandling, I was able to get this structure up and needled through the eyebolts on the TMS Table. Other than the possible parts above, the TMS is pretty much ready for ISI balancing.
Note: will keep the TMS Upper Structure "free" (vs. locked).
After the coarse IAS checks were finished this morning, Travis and I fully unlocked the ETMy QUAD which repositioned all of the masses into their pre-aligned posistions. This also removed alot of extra locking bracket payload. We then pulled all of the shield and optic cap payload and added the witness plate mount such that the total payload of the QUAD was within ~a lbs of being correct. We then reclamped some of the masses lightly such that SEI can load masses around upstairs on top of the ISI in order to continue their work.
Kyle investigated.
Cyrus and Dave
around noon the /ligo file system became unavailable, causing the workstations to freeze up. We rebooted cdsfs0 and restored the file system. We are in the process of restarting the workstations to give them a clean NFS mount.
Seconded.
(Doug, Jason, Hugh, Betsy and CO) First look at the ETMy in chamber measurements are very encouraging. Results: Longitudinal was short by 0.5mm from absolute, tolerance is +/- 3.0mm, Lateral position is 0.35mm to the south, +/- 1.00mm Elevation position is high by 0.35mm, tolerance is +/- 1.0mm Optic is set lightly on EQ stops, but for a first look to identify any need to move the ISI or SUS this is very reasonable results. The arm cavity baffle was rough positioned to accommodate the line of sight from the spool and currently rests unattached on its installation table so use caution when working around it. When fully pay loaded, cabled with the ETM suspended we will do the the fine alignments of the positions and optic angles
Forgot to mention that the particle counts were 3-4 counts on the .3 microns scale and 1-2 counts on the .5micron scale at the spool while we occupied that area. Kudos to the folks that keep the VEA clean and well stocked with garb and cleanroom supplies.
The vertical position is actually high by 0.9 mm, not by the 0.35 mm originally stated.
The readback channels for the corner station ring heaters seem to not have been working properly since last Friday. I've attached a graph that shows that the ring heaters seem to have turned off at 02-21-2014 22:5:32 UTC. Judging from the ALOG around that time, there were a lot of reboots going on in software, I'm not sure about hardware reboots. However, Kiwamu says that the PRC power level is looking like the ring heaters are on just based off of the amount of loss he measured. He also advised that since the system is working well, I should hold off on trying to power cycle the TCS chassis until a later time but at the first chance I get, we should try to resolve this issue. The ITMX ring heater is also displaying similar weirdness, which is expected since they share the same chassis and PLC.
Kiwamu, Sheila, Thomas This morning seemed to be a good time to investigate this issue. At first we saw that the PLC3.pro was connected to EPICS but not to the System Manager, i.e. the ADC channels were not getting from the hardware to the TwinCAT software. We tried re-running the install scripts but it did not fix the problem but it did help us figure out that there were some channels deleted recently. Daniel let us know that if there are some additions or deletions, we should re-map the configuration before recompiling. This solved the problem!
[Ed, Evan]
We are preparing to make a measurement of the length of the PRC using the phase-locked auxiliary laser technique described by Chris Mueller (T1400047). Previously, this has been used to measure the Livingston IMC length (LLO alog 9599).
We set down a 520 mW Lightwave NPRO on the IOT2R table, along with a Faraday isolator and steering mirrors. We will inject this beam into the PRM_refl side of the IOT2R periscope. The beam will hit the back of IM4, and a small fraction (2400 ppm) will be transmitted toward the PRM. This gives 1.2 mW of auxiliary power on the PRM, compared to 9 mW of 45MHz PSL single-sideband power on the PRM.
Most of the auxiliary power should reflect from the back of IM4 and return to the IOT2R table via the IO_forward side of the periscope. For mode-matching, we hope that we can simply send part of the IO_forward beam onto a New Focus 1611 and maximize the observed beat. Currently, there is 3 mW of power in the IO_forward beam.
Using this beat, or otherwise, we will phase-lock the auxiliary laser to the PSL carrier beam. Then with PRMI locked on the PSL sideband, we will sweep the offset to the auxiliary PLL and monitor the RF coming out of POPAIR_B. We should see the strength of the RF reach a maximum whenever the auxiliary beam is coresonant with the the PSL sideband. By tracing out the Lorentzian profile of the RF amplitude across successive resonances of the PRC, we can extract the FSR of the PRC. Given a design length of 57.6557 m, we expect an FSR of 2 599 850 Hz. If we can measure the FSR to within 100 Hz, we can get the PRC length to within 2 mm.
Yesterday we got the NanoScan back from EX and Ed used it to measure the beam parameter coming out of the Faraday isolator. The waist is about 100 µm and located more or less in the middle of the isolator. The size is maybe a bit smaller than we want, but we appear to be able to get more than 90% of the power through, with a reasonably Gaussian mode.
After the FI, we placed a HWP to set the beam to be s-polarized. After this, we placed a New Focus 5104 as a first steering mirror. As a second steering mirror, we use IO_PRMR_BS1.
We removed a lens from between IO_PRMR_M3 and IO_PRMR_BS1. It was unlabeled, and anyway there is nothing after that lens except beamsplitters and dumps.
We did an ALM optimization to mode match to the PRM. Joe Gleason's IOT2R layout (D0902284) gives the distance from the bottom of the IOT2R periscope to the PRM as 3.6 m. The spot size is 2.24 mm, with a ROC of 11 m (T0900407, p 5). ALM told us to put an f = 500 mm lens about 3 inches before IO_PRMR_M3 ("before" meaning "closer to the FI").
We put down two irises in order to constrain the pointing of the PRM_Refl beam. We then blocked this beam and steered the auxiliary beam through the irises. With a little tweaking, we were able to see our beam coming out on the IO_Forward part of the periscope. We measured the power of this beam and found that it was only about 5% of what we were putting in. This initially confused us, until we realized that our path in HAM2 has to go through a 90% reflector which is intended for the ISS. Given that IO_PRMR_BS1 is a 90% reflector and ROM LH1 (in HAM2) is also a 90% reflector, we in fact only expect 90% × 90% × 10% = 8% of the power to come back onto the IOT2R table.
Yesterday, we put down the New Focus 1811, aligned the PSL and auxiliary beams from IO_forward onto the PD. We found a beat with the auxiliary laser temperature around 37.7 °C. By tweaking the auxiliary input pointing, we were able to get -4 dBm of RF beat out of the 1811 with about 1 mW of DC power from each beam in front of the PD (so 2 mW total).
We were then able to implement a PLL using an HP function generator and the LB1005 servo box. We set the function generator to ~30 MHz and +7 dBm, and used it to drive the LO of a mixer. We took the beat and put it into the mixer RF. The IF was terminated, filtered at 1.9 MHz, and then fed into the LB1005. The output of the LB1005 was then fed into the fast input of the laser. We were able to catch lock by turning the laser's temperature control knob to push the beat toward 30 MHz. The lock would hold for about 1 minute before the controller saturated. To maintain sanity, I suspect it will be necessary to implement a slow temperature loop to relieve the fast controller.
We thought it prudent to have a spare PUM in-hand for the upcoming monolithic builds, so yesterday we started bonding ears to the PUM ITM03. Gerardo sucessfully placed an ear on the S4 surface with an error of under 0.01mm misplacement (0.1mm is the tolerance, so well done Gerardo!). On to the S3 ear...
Like NBC jinxed all of the ice skaters by praising them just before they fell at the latest Olympics, I spoke too soon about the PUM ITM03 ear. Just after writing the above alog, Gerardo and I inspected the S4 ear and discovered a large bubble near the corner of the ear. It had a small fiberous particulate in the bubble. SOmehow, after monitoring for 2-3 hours, this fiber migrated into the bond. We had placed a LIGo-approved Vectra Alpha 10 cleanroom wipe over the S4+ear flat for the night in the event a random bug decided to perch, so possibly this added to the particulate. Da*m.
With Mr. Barton's assistance, we loaded the mass into the ultrasonic cleaner and bathed it in water. Within 4 minutes the ear came off. The mass is now reloaded at the wash station and we'll work on the S3 ear we were already prepped for today.
Bubble is shown in far corner of ear in this picture.
Further comment to the events above - Margot and Gerardo found this PUM to be dirtier than normal when they pulled it out of the cake tin many weeks ago. AT that time, they did a methanol cleaning of the entire mass. When Gerardo and I were cleaning the flats of this mass, we also noticed that it still seemed dirtier than "normal" - meaning, when rinsing, the water did not run on the surface as we had seen on other flats. After we performed the standard cleaning of the flat, the water behaved "normally", meaning it clung to the full surface and "sheeted" off. After we removed the contaminated ear, we recleaned the flat, expanding the surface area getting cleaned to the entire flat, not just the area when the ear gets bonded as is the typical procedure. We hoped this would remove particulate that was previously closer to the bond area. During the second ear bond attempt, we also did not cover the bond overnight with an alpha 10 wipe, since we were skeptical of the origin of the fiber which showed up in the bond.
