Transfer functions are running overnight on HAM2-ISI. Jim pulled the covers away witht he metal rods taken from HAM3. Covers should not rub against the ISI this time around.
B&K hammer test was made monday and tuesday last week with Betsy and Travis on HAM2 and HAM3 chamber for MC1-MC3-PR3-PRM-PR2 suspensions
The measurements have been taken with :
Pictures attached are showing position of the tri-axis accelerometer, and hammer hit locations for :
The following pdf document shows the different measurements, with comparisons between VA on / off for PR3 and PRM, and comparisons between LLO and LHO measurements.
As required for the ISI tables, resonnances of the structure below 150Hz (marked by the black dotted line) are damped by the vibration absorbers (page 9 to 12 to see their effects on PRM and PR3)
Data have been exported and plotted following the operations manual wikipage.
Label on the first picture should be MC1 and not MC3.
Phase 3a transfer functions have been running last friday on PR3 supension. Transfer functions are consistent with model.
First pdf shows TFs with damping on vs model, the second one shows TFs with damping off vs model
PRM was left in it's parking position after IO work last week, and this was disruptive to transfer functions last Thursday. Today I put PRM into it's aligned position, so new transfer functions can be made. The PRM PARKED position, which sends the IFO REFL beam out a viewport atop HAM2, is: P = +2500 urads, which is 4688 in counts of drive Y = -6000 urads, which is -16084 in counts of drive The PRM ALIGNED position, which sends the IOF REFL beam into HAM1, is: P = +2000 urads, which is 3750 in counts of drive Y = +50 urads, which is 134 in counts of drive Aligned snapshot of the medm attached.
Prior to HAM3 chamber close up, PRM transfer functions have been running last friday.
The attached pdfs show :
Measurements are consistents with model and previous data, and PRM has been approved for Phase 3a testing
0730 Justin refilling xtal chiller in diode room 0900 LVEA transitioned to Laser SAFE 0920 Filiberto pulling cables along HAM 2/3 0930 Thomas working on OpLev near HAM 2/3 0945 Cyrus to EX 1015 Cheryl torquing bolts HAM 2/3 1020 Arnaud taking quick measurement at BSC2 1030 Gerardo working on periscope and baffle alignment @BSC2 1250 Arnaud taking spectra at PRM 1350 Pablo and Michael R working on periscope assembly in H2 PSL enclosure
Prior to HAM3 chamber close up, MC3 transfer functions have been running last friday.
The attached pdfs show :
Measurements are consistents with model and previous data, and MC3 has been approved for Phase 3a testing.
The only particularity to notice is that the damping in YAW doesn't provide much effect
Prior to HAM3 chamber close up, MC2 transfer functions have been running last friday.
The attached pdfs show :
Measurements are consistents with model and previous data, and MC2 has been approved for Phase 3a testing
- Cheryl, Chris (Apollo) HAM2 and HAM3 IO component bolts are now torqued to spec. The actual inch-pounds is unknown, as we were working at the end of the range of the torque wrench. I checked the 1/4-20 bolts that are holding down cables and found a couple in each chamber that were loose - IO and SUS. I found a couple IO 1/4-20s in HAM2 that seemed to be over torqued, and backed out one of them. This clears all of the known IO mechanical changes needed before close-out - HAM2/3 given back to SEI.
I restarted the user model and the IOP model this morning, there was a 55 second timing error that was causing excitations to behave badly.
Kiwamu I. Thomas V. We've aligned the in-chamber optics for both HAM2 and HAM3, this is with the ISI balanced and locked (hopefully this does not change the pitch and yaw significantly after pumpdown and unlocking). We only turned knobs on the optic mounts and did not translate anything on the ISI table so this should not have changed the #balance for @SEI. The beams going in and coming out of the chambers look clean, I believe everything that needs to be done for these optical levers can be finished outside of the chamber.
HAM's 2 & 3 are locked for AOS closeout. BSC2 is unlocked, but it looks like we have a bad CPS there, so we may be locking again shortly.
BSC2 locked, then unlocked again to facilitate change out of a bad CPS. Now, it's floating, while Gerardo Sr. is in chamber with IAS for lollipop baffle alignment. HAM2 is also unlocked again for SEI checkouts, while HAM3 remains locked. Phew.
Beamsplitter transfer functions have been running over the weekend in order to fix any issues during the day if needed.
The attached pdfs show :
Vertical degree of freedom is noisier than expected between 1.5 and 3Hz (3rd page of each pdf).
Gerardo went into the chamber, checked the EQ stops, and nothing is apparently touching. When the chamber will be free tomorrow during the day, I will run quick DTT measurements for the vertical degree of freedom, between 1 and 3Hz and see if it's still noisy. There were no need of taking the night for full measurements since the other DOFs are fine. I let the night to Vincent for ISI tfs if needed.
I ran a DTT transfer function on the vertical degree of freedom of the beamsplitter this morning
New TF looks nicer than the old one from April 12th, meaning the beamsplitter is healthy and passed Phase 3a testing
Will run a full set of TF tonight, for our record.
Data of the DTT measurement has been saved in a matlab structure named :M1VtoM1V_20130422.mat under SusSVN/sus/trunk/BSFM/H1/BS/SAGM1/Data and has been commited to the svn
Last measurement on the beamsplitter has been taken monday night April 22nd with damping on and off, before pumping down BSC2 chamber.
One thing to notice :
Vertical degree of freedom remains noisy around 2Hz, as on April 12th, even though dtt transfer function from aLOG 6158 doesn't show any issues. It could be that when taking TF with matlab, the drive for that frequency band is not high enough. I will try with higher gains in the MATLAB_TFs.m script and see if it changes anything.
Kiwamu and I went into the PSL this morning, and added two irises to the ALS doubling path (labeled ALS iris 1 and 2) to use as references for the alignment into HAM1 and out onto ISCT1. We moved the second lens in that path about 1.25 inches closer to the periscope to get the beam better collimated leaving the table. A mode scan of the resulting beam is attached. The spacing of the measurements is small compared to the Rayleigh range, so the fitting is not great, but we have a pretty well collimated beam with a radius of 3.3 mm coming onto ISCT1 now. We also aligned the path up o the SHG again. For the purposes of calculating a mode matching solution, the first steering mirror is 4+1/2" from the bottom periscope mirror, the second is 18+1/2 inches away, and we have about 13 inches after the second steering mirror in which we can place the SHG.
Again, the beginnings of a list - Things we need to address during the next vent opportunity (after HIFOy test):
Cleaning of BS optic
Set top stage BOSEMs in position to account for buoyancy (flat out forgot to do this and ran out of time)
The beginnings of a list - Things we need to address during the next vent opportunity (after HIFOy test):
PRM optic cleaning (if not all optics on table)
Although it "passed" the data round, investigate further some PR2 minor TF cross-coupling (SUS: see emails circa 4/11/2013 Kissel/Pele/Barton
Recenter any outstanding lower stage AOSEMs
Kiwamu, Sheila We removed the guillotine on the viewport and saw that the beam is nice and Gaussian. The guillotine was also probably causing polarization problems, now that we have removed it the ghost beams off the 5% reflector and the mirror after it are much better. We then measured the beam profile (with PLCX-50.4-309.1 installed right after the periscope mirror, at 0.223 in the units of the plot which start from the inner edge of the enclosure walls), the data and a fit is attached. Propagating this beam back towards the PSL gives an answer that does not make much sense, I would need to be off by 2cm in the lens position to get a reasonably collimated beam to propagate 10m back to the PSL, but I double checked my measurements and they seem to be OK. The conclusion is that if we want to adjust the lenses to make sure we will not have problems with clipping on the PSL periscope upper mirror (or other places) in the future, we probably need to measure the beam inside the PSL first.
Kiwamu, Sheila,
How does one view the beam profile file(.fig)?
thanks
You need Matlab to view the fig file.
here's a PDF, sorry about that.
Transfer functions are running over the weekend on HAM2-ISI as well.
HAM2 was unlocked. It was a bit difficult the get the tight covers to stay away from the ISI without the rods we usually have (used on HAM3, see attached pictures). I added a couple clamps to keep the sheet in place over the weekend.
It looks like the covers rubbed against the ISI afterall. We need to take the cover rods from HAM3 chamber, put them on HAM2 and take a new set of measurements.
