The ALS SHG is now producing 0.57 mW of 532 light. One thing that I noticed while optimizing things is that the performance of the dichroics depends quite a bit on the polarization of the IR beam, so I had to add a second dichroic so that I could optimize the polarization. I also moved the DC PD into the main green path to have a better monitor of the green power than the pick off beam. Some power measurements in the doubling path: Infared powers: 240mW coming onto table Pick off for IR DC PD: 9.85mW remeasured main beam after pick off: 247mW (measured at waist) The first dichroic rejects 239mW of IR IR through first dichroic varies with polarization from 200uW to 66uW, I need to remeasure the value now that I optimized the polarization After the second dichroic I don't see any light when the SHG temp is far from phase matching (not more than 2uW), which is independent of polarization. A partial phase matching curve is attached. The thermistor calibration is only rough, so the temperature read out is not really linear with the actually temperature over 10s of derees C, so the measured curve is not exactly a sinc function. Last night I left the SHG running overnight, the second plot attached is the effective nonlinearity (green over IR^2), conversion efficiency (green/IR), green power and IR power each normalized to their means. You can see that over 15 hours, the power from the PSL slowly drifted up, which the green power also did. All the fluctuations except for one glitch at 13.5 hours are well within the 5% requirement from T1300174. The last plot is a histogram of these normalized values, the standard deviation of the green power is 0.67%. The data and m file are also attached.
The ITMy elliptical baffle was also aligned in lateral and vertical position. Its final aligment errors are:
The ITMx elliptical baffle was not aligned due to a mounting issue described in aLOG 6104 and its comments. This baffle was left in the chamber so as not to hold up progress on chamber close out for the HIFO-y test.
Andres R. & Jeff B. We completed taking the Transfer Functions and Power Spectra data for I1-PRM. The data files are attached below. There is a small peek at 0.85Hz, which is suppressed under damping. All scripts and data files have been committed to the SVN repository. We will wait for the testing group to review the results data before taking additional action on I1-PRM.
It would appear that the undamped TF measurement (2013-04-17_1050277177_X1SUSPRM_M1_ALL_TFs.pdf) has been accidentally omitted from the original comparison plot (allhstss_2013-04-17_Phase1b_X1PRM_ALL_ZOOMED_TFs.pdf). I've therefore re-processed the comparison, this time including the undamped TF measurement, see plot attached below. The key for the relevant traces are as follows:- Blue trace = Model Prediction. Red trace = X1 PRM (2013−04−17_1050277177), Phase 1b. Undamped. Yellow trace = X1 PRM (2013−04−17_1050295239), Phase 1b. damped. The TFs taken for the I1-PRM show good agreement with the model and are consistent with measurements taken for other HSTS suspensions, at both sites, during the same phase of testing. The ~0.85 Hz feature observed by Jeff B coupling into roll and pitch DOFs I believe is the first vertical mode, which appears particularity energetic (maybe due to noise or excitation), with its energy bleeding into the other DOFs. Hence, damping loops suppress this feature. Therefore, PRM is approved for India. n.b. As of this entry I have committed the updated plots and scripts to the SUS svn (so please svn up the X1 test-stand).
The EDCU had problems with the ECATC1 ini file giving false connection status numbers. I removed this ini file from the DAQ and restarted at 09:39
Attached are plots of dust counts requested from 5 PM April 15 to 5 PM April 16. I have not included plots of the counts in the optics labs, because of the 'nan' in the data when I rebooted the IOC to test a new version of the code. I did this starting at 3:06 PM April 16. The modified code should fix this bug and is scheduled to be installed next Tuesday.
Door covers are so tight the touch the ISI on both sides of HAM2. IO closeout still to do:: - check beam on psl wall - flash IMC - align REFL to HAM1 - needs coordination with ISC crew - align HAM2 QPD - check all baffles - check POP/ALS path in HAM3 - align West side of HAM2 beams with viewport simulator. Viewport simulater was crammed in the HAM2 clean room across the steps, so had to be moved, and will need to be wiped again before hanging on an open HAM2 door.
The two steering mirror assemblies, D1101851, are installed in BSC2. They went in fairly smoothly. One hitch is where the support bracket attaches to the chamber's lower bracket; the weld from the lower bracket to the chamber wall kept the two surfaces from mounting flush. The two mirrors are NOT installed yet. They oxidized during their bake and I am still working on figuring out if anything should be done about that. The mirrors shed a little, but it seems as though they are not shedding anywhere near the level that the chamber itself is.
We set up Viton Pads under HAM3-ISI balancing masses. The size of those pads is the same as the size of LLO's. However we set those pads under 1/2 the mass LLO uses, in order to rise the corner frequency of the mass+Viton stack.
Comparison before/after is attached.
The Viton Pads improve the 310Hz peak in V efficiently, by a factor > 5 without any drawback to it. Results are satisfying enough for now. We may try other configurations next time the chamber is open.
This Viton Pads Efficiency Test was plotted in the cartesian basis. Results are attached.
Best improvements can be seen along RX and RY, in the 310Hz region. Suspension modes can be seen there and they are known to be coupling with the ISI.
Plots show that the Viton Pads we used helped limiting the impact of SUS/SEI couplings, on the ISI's Transfer Functions.
Having those viton pads should also facilitate the design of control loops, and eventually allow pushing the performance a bit further, as more gain margin will be available.
08:00 Reset all the alarm handlers 09:30 Start measurements (Transfer Functions) on HAM 3 ISI – Hugo P 10:45 Start/Continue assembly work on H2 LAE PCAL – Pablo 12:10 Work (Inspection)on LVEA main crane – John Worden 13:45 Cable work by HAM 4 on the LVEA – Filiberto C. 14:49 LVEA Transitioned to Laser Hazard - Cheryl 15:00 IO Alignment on HAM2/HAM/3 in the LVEA – Cheryl
Restarted the DAQ at 15:14 and 15:17. Added all h1seib3 systems (IOP, ISIITMX and HPIITMX). Also added back the ECATC1.ini EDCU file to support slow controls commissioning.
Needed two starts, three of the Beckhoff channels do not seem to exist and were commented out.
the DAQ restart glitched data from the following front ends: h1susb6, h1susauxb6, h1sush56, h1susauxh34.
MX streamers were restarted on all, DAQ status became GOOD on all.
Measurements are complete on HAM3-ISI. The Apollo crew can proceeed there.
Crane work continued:bearings for main crane arrived, one installed and packed; still working on X End crane. HIFO-related viewport checklist being worked. Test Stand cleanroom transported from Y End to X End. Frame re-assembled.
Gerardo finished up the optical lever periscope for the BS. The Y-arm baffle is aligned. The Y-arm baffle needs to have the brackets removed to fully suspend it...do not forget this The X-arm is not aligned due to the mounting bolt pattern issue he encountered The platform remains inside under the X baffle IAS needs to finish breaking down our equipment and stowing it
BS optical lever periscope installed, is set 7.5 degrees below horizontal. 3 photos attached, BS elliptical baffle from AR side, a comparison of the BS optical lever periscope (before and after photos), and a view of the installed periscope.
Jim W. Thomas V. We have removed the locking brackets on the ITMY Elliptical baffle so it is fully suspended (and rather vulnerable). We left the ITMX Elliptical baffle with the brackets still attached in case any other alignment work or modifications needed to be done. If it is decided that ITMX's brackets should be taken off, it will be done as well.
While I was in chamber for Thomas' work, I did a survey to see if any tools had been left in any of the usual nooks and crannies. I didn't find anything, so I think the chamber is clear for close up. I will be in again, probably tomorrow, to wipe down the floor and will do another check.
The Y-Arm elliptical baffle is aligned within spec. < 3mm lateral and vertical However, the X-arm continues to give us mounting errors. This may require the mounting base to have existing holes elongated in order to mate up with the threaded holes on the stage "0" or at least an investigation into why we are unable to fit it up in its aligned location. If holes need to be slotted we will loose a week with the dissembling, modifications, clean and baking reassembly and installation. A week longer for the spool to be out. Another option may be that we can remove the baffle modify it and reinstall and align it just prior to installing the ITMx while we have an open path. I will notify Calum, Lisa, Mike Smith, Mike Landry and Brian as LLO may see the same problems
Items to remove from ITMY elliptical baffle: - 1 Variable Height Adjustment Bracket (D1102321) - 1 Transport, Locking, ACB (D1101285) - 10 1/4 x 20 bolts and washers, holding both items above The ITMY elliptical baffle was left locked, due to the possibility of staff going in chamber in the near future, the flexure that suspends the baffle is very small and fragile, vulnerable to twisting forces.
Photos of issue with ITMX Elliptical baffle, photos were taken as the baffle sat within tolerance, but there was no clearance for the mounting bolts, since we only see a little bit of the mounting holes.
Mitch, Jim, Hugo,
HAM2-ISI was repayloaded, rebalanced, and its lockers (all) were adjusted. We gave HAM2 back to SUS so they can proceed with testing.
CPS readouts (counts) with the ISI locked, and unlocked, are displayed below.
| Locked | Unlocked | Shift | |
| H1 | -3355 | -2861 | 494 |
| H2 | -2622 | -2604 | 18 |
| H3 | -121 | -713 | 592 |
| V1 | 344 | 709 | 365 |
| V2 | -436 | -534 | 98 |
| V3 | -364 | -820 | 456 |
Even though they are a bit mis-centered (away from 0cts), CPS Targets are far from contacting the sensor. We will leave the CPSs un-zeroed and use a bias in the control loop, as we have done so far.
Cables rubbing against the chamber/support tubes could be an issue for HEPI commissioning. We took care of dressing the cables away from the chamber and the support tubes, as we could without unplugging anyone (See attached Pictures). It is good practice to always adjust installed cables so they are cleanly dressed, away from the chamber and the support tubes, before connecting them to a feedthrough.