The LIGO Executive Committee Agenda for Monday May 2, 2005 will be:
(Meeting time: 10:30 am Pacific Time)
Special Items:
no report
LSC MOUs and Research Plans and Progress Reports
LSC updates for Feb. 15, 2005 to Aug. 15, 2005 and Progress Reports through Feb. 15, 2005
A site teleconference was held on Thursday, April 7, 2005. The following issues were among those discussed:
>From: Ed Chargois <chargois_e@ligo.caltech.edu>
>From: Linda Turner - turner@ligo.caltech.edu>
>From: Cleveland Mak <mak_c@ligo.caltech.edu>
>From: Esther Cunningham <esther@ligo.caltech.edu>
>From: "Brambila, Ruth" <Ruth.Brambila@caltech.edu>
>From: Gina Salone <gsalone@ligo.caltech.edu>
>From: Florence Kaufman <fkaufman>
>From: irena@ligo.caltech.edu (Irena Petrac)
>From: Ed Jasnow <jasnow@ligo.caltech.edu>
>Irene Baldon
>Julie
Hiroto jhiroto@ligo.caltech.edu
Nothing significant to report.
>Dorothy Lloyd
No progress to report this week. The Annual Report for the Visitors Program is basically complete and entered into FastLane ready to “push the button.” Will be helping Fred Raab with the I2U2 Proposal, which is collaboration with Fermi Lab for some outreach activity.
A proposed draft has been distributed for outlines for the Annual Report for Operations and a Proposal for an Extension for FY 2007 and FY 2008. Some comments have been returned. We will begin working these documents pretty furiously between now and August 1.
[Some comments excerpted from comments provided by D. Shoemaker. –pel] Scott Reedy of Go Engineering demonstrated the Agile Document Management System on Wednesday, April 27, 2005. It appears that the system might work very well for LIGO. The system targets a development and manufacturing environment more so than other systems that we have looked at. The workflow tools are particularly complete and flexible. There are built-in mechanisms for QA checks, tracking installed hardware, redlining using built-in tools, and the like. URLs to documents are not directly delivered, but a URL for the 'file card' from which the document can be found as an attachment is available -- one more click. It is not set up to publish to the open web, and for those documents which should be completely open, we would need to have a separate step outside of Agile (but one that sounds relatively straightforward to implement). This may cause us to rethink what we want to be public and what is not, for better or worse. An ORACLE database is used, but it is managed by Agile and we would not need any local expertise.
Cost may be an issue. Engineering help will be required to "sell" this approach based on the added capabilities that the system would provide for them.
>From: Cindy Akutagawa <cindy@ligo.caltech.edu>
>From: Bill Tyler tyler@ligo.caltech.edu
Nothing significant to report. Seems like all is as ready as it is going to be for the LHO Safety Audit on Monday (2 May).
Highlights from this week's elogs:
The L1 interferometer's inspiral range improved to 10 Mpc last week, after it was found that the of non-resonant sideband modulation frequency was 10Hz away from being an exact 5/2 multiple of the resonant sideband. This was producing both a line around 100 Hz and some broadband noise, which dropped away with this simple adjustment.
The anti-symmetric port WFS Gouy phase telescope was modified in attempt to improve the WFS1 optical gain. The first modification was not successful due to the reduction of the beam size on the photo detector. The design was modified and new lenses were ordered to allow adjustment of the Guoy phase without adversely affecting the beam diameter.
Other interferometer noise investigation and improvements:
Nothing of substance to report this period.
Added two fiber interfaces to the router tuesday night which required about 10 minutes of downtime. This is the flashed card that Syskonnect sent from Germany that finally arrived with a bug fix. However, it only works in one of the two PCI-E slots. I have emailed them and they claim to be aware of the problem and have since released another patch which requires flashing the EEPROM on the card.
Working on a security package that will be installed on the router. It will work as a basic IDS on the border which should give me an idea of the number of portscans, etc. that we see on a regular basis. It also has the ability to automatically block offending IPs. I will have to make sure that it has a facility to whitelist some addresses before I enable it.
Still working on an LDAP/mail server migration. Some parts of it are in place and some of the configuration is done. This will likely take a couple more weeks to finish testing and possibly roll over to it.
Several user support issues this week.
Working on renewing our Matlab license maintainence. Received a formal quote yesterday.
Working a Maple software issue with the Caltech license server. For some reason we cannot authenticate against their license server, even though the software@caltech folks claim there is no filtering on those ports by address.
1) HPLF news: The 100 W laser survived the 7 days burn-in test in constant current mode and another 2 days burn-in test in constant power mode. This means that the laser is now all clear for shipping back to LLO. We have also obtained a LabView code from IPG, which will be used for controlling and monitoring the laser during long-term testing.
2) Performed additional Melody AdvLIGO mode cleaner simulations by changing the diameters and thicknesses of the mirrors a little in order to study the stability of the solutions as requested by D. Reitze. No significant changes were observed and I will resume writing up a report.
3) Was assigned to study and come up with a solution of the REFL port beam drift which has been recently been observed at higher laser powers. This drift is probably caused by thermal lensing in the Faraday Isolator downstream polarizer causing a beam deflection around 1 mrad. An inventory of PZT available at the site was made and two was found. Have been trying to identify them and is setting up a test station in order to measure their range of motion.
no report
see also the CDS weekly meeting minutes in the commissioning archives
no report
Jay Heefner reporting
Peter King
The timing jitter for the timing system, in its various incarnations, was measured. The mean jitter for the 4 MHz clock straight out of the Brandywine was measured to be 0.676 ns. For the system with the clock fanout board, 2.627 ns and for the system using the electro-optic link, 25.268 ns.
Ben Abbott
1) Todd has finished stuffing 5 of the 24.5MHz PDs, and is working on some more that will be tuned to 24.5 MHz and 29.5 MHz.
2) I am tuning a 61.2MHz PD for LLO.
3) I have put an order in the machine shop to make more of the ISS PD bodies so that I will have plenty to give to the sites for the newer configuration.
John Zweizig
This week I have been evaluating the V40Z (Solaris quad opteron box) as a possible online DMT computation platform. The DMT software installed on an LDAS V40Z box after solving a few minor problems. Preliminary benchmarks indicate that the Opteron performance is close to that of the Sun sparc after scaling by clock frequency (i.e. the 2.2 GHz Opteron executes DMT code about three times as fast as the 750MHz ultrasparc-III). Still to be determined is whether the V40Z box can handle 10s of DMT processes in parallel and whether the shared memory data distribution mechanism runs efficiently on the new platform.
PeterKing
After a suspected problem with the shutter in the 40m Lab 10-W laser, a shutter sub-assembly was requested from Lightwave.
Mike Smith
I verified analytically the beam sizes Dave Ottaway calculated, for the modification of the 4K TCS system with the 30W CO2 laser. I created a ZEMAX model of the new 30W TCS system.
Using the ZEMAX TCS model with paraxial Gaussian beam propagation, I can evaluate the effect of a limiting aperture on the visibility of Phil Willems' proposed mask design with radial spokes. It appears feasible to place a limiting aperture in the vicinity of the first periscope mirror. This aperture will pass the central Gaussian heating beam with negligible attenuation and will provide a simple means for changing the visibility of the projected spoke pattern on the ITM.
Ken Mailand
I gave Phil Willems information tuesday on the photo etching method of producing the laser mask.
Lee Cardenas, Liyuan Zhang
OTF Lab. (W. Bridge) No Change
This chamber still locked with two samples, white Ceramabond, and disks of TRA-BOND #2254 color light brown epoxy. Cavity is clean We are preparing the REO mirrors to be tested for contamination. These mirrors were tested for absorption at Stanford after different cleaning procedure. We will make our own cleaning procedure and introduce it into the cavity. These mirrors were tested before and found to have a large scattering
Absorption Test Measurement prototype in standby
Scatterometer system in progress
\We have completed the scanning of the fused silica mirror: 4ITM05, (scattering loss ~30ppm ) for transmission. Results of data will be released by Dr. Zhang
We are making the frame to hold the new HEPA in place.
The Quantronix 60 watt laser In progress
Preparation for the large mirror absorption test
We have re-wired the power supply connection to match the power phase from the building. We made all the cooling connections and turn on the laser. Laser power is ~32 watt @ 30 amps of current. It is stable good mode.
OTF Lab at Lauritsen ROOM 38
Cavity #3
The contamination test for (20) pieces of Glenair Micro-D-connectors still in progress. Cavity is locked and we are taking measurements for absorption and ring down for contamination loss every day. So far so good It needs another month for the test to be completed.
Cavity #2 no change
This week, Helena checked on the status of the mirrors with advanced
coatings, and they are on schedule for an end-of-May delivery.
Akira achieved first lock in the bond-noise experiment. There are some oscillations in the control servo whose origins we do not yet understand, but this is a common occurrence when putting together a new experiment. Seismic isolation is quite good, and residual noise in the pendulum is small enough that the shadow sensor stays more or less in the linear regime, even with the loop open. Akira is in the process of measuring the transfer functions of the servo to compare with expectations, and he is able to do so without closing the loop.
Jay and Alex are almost finished with the data logger for the bond-noise experiment, lacking only an inexpensive GPS receiver with a hardware interface. They expect to have something by next week, but if not, they can run temporarily with a function generator in place of the clock.
There was a lively discussion at the TNI meeting on Thursday about whether or not we should switch from 4"x4" mirrors to the 3"x1" mirrors used in Q measurements. The hope was that by standardizing on a common mirror size, there might be cost or schedule savings. All indications are that there are not. Going to 3"x1" mirrors at the TNI would require retooling of both the TNI suspensions and Jean-Marie's coating chamber, and the savings in material cost are expected to be comparable to the retooling costs, if not smaller. At this time, the best course of action appears to be to continue using 4"x4" optics for direct, broadband noise measurements.
We have been investigating the ground noise amplification in the BSC support structure. Measurements have been taken of ground motion to the motion of the top of the pier in 6 DOF, a report will be on the Lasti ilog in the near future.
The sys-id of the BSC in a pseudo-advanced LIGO configuration. Design of the control laws has started.
Ken is working on a FEA model of the BSC support structure and some nice progress has been made this week.
(Hiro) Based on various FFT runs and analytic calculations, details of IFO including mode matching etc, seem to affect little on CR recycling gain, except for the mirror surface phasemap.
The recycling gain can be written as follows, which has only major contributions included. (No phase map effects included) gain = 4 / T(RM) / ( 1 + Lxy )^2 4/T(RM) is the maximal recycling gain, which is 142 using T(RM) =0.028.
Lxy is due to various losses. Using T(BS) = R(BS) = 0.5, Lxy is written as 2 * ( Lx + Ly ) / ( T(ITM) * T(RM) ) where Lx = Loss by ITMx + Loss by ETMx + Transmission of ETMx, same for Ly.
Based on FFT runs, mirror surface phase maps tend to reduce the gain by around 20%.
The major factor is the loss in the arm. Loss per arm per bounce of around 50ppm accounts for the recycling gain of 70-90. Based on FFT with mirror phase maps, the loss per arm for 4k IFO should be around 100ppm, not 150ppm, to have the measured CR recycling gain of 45.
(Biplab) Worked with Rana and Matt on optimization issues of WFS. As is known (elog Jan 27), WFS at LLO is working even though its Gouy phase settings are not at the optimal values obtained from FFT studies. We tried to have a proper telescope scheme that can provide the desired 90 degree Gouy phase shift to the beam in between the beam-splitter and WFS1. Suggested a solution with 2 reasonable lenses but it needs large (of the order of meter) optical path that cannot be easily accomodated on the bench.
Matt came up with another nice solution with 3 stronger lenses that could reduce optical path but strong lenses might have other issues to deal with. Also, it shows that anything that allows smooth adjustment of Gouy phases requires at least 50 cm of optical length after the position of 1st lens on bench (fixed due to other constraints) in theptical path leading to WFS1.
(Hiro) Working with Keita and Rick to estimate the effect of the surface roughness on the g-factor measurement. Provided a setup on halfdome for Keita to run FFT himself, and provided a minimal documentation.
(Monica) Preliminary simulations of sweeps for error signals have been done with the e2e package for the 40m interferometer, but the used velocity is still too fast to investigate the DC response of the real interferometer. A slower velocity needs longer simulations if one maintains the 40m configuration. Just to verify the DC response, one can use the trick to slow down the velocity and at the same time decrease the length of the arms; in this way the simulation will be faster.
(Matt) Continued work on simulation framework for Advanced LIGO. Some boxes now have contents, others remain placeholders to be filled later. Draft documentation on the organizational structure of the simulation is done, but more detail is required.
(Hiro) I modified modeler codes to support the work of Matt building the advanced LIGO detector simulation.
(Bruce) Working on speed issues regarding bundles for save and node validation.
(Melody) Continuing on fixing existing Problem Reports. Currently working on the user interface for allowing the user to choose the display for primitive nodes: graphic or text. Implemented an option to display the rename/delete dialogs to be displayed only once.
Fixed PR 466: external view window size change no longer affects the internal view window size.
Checked in all modified codes to CVS.
cmonClient is being enhanced by addressing the issues related to PR 2724 (modify resource vars), PR2617 (headers for resource vars) and PR2336 (sorting of data by clicking on column). These changes will be part of the nightly builds by early next week.
Ran the weekly integration and system tests on LDAS version 1.5.53. All tests passed without incident. Updated compresstest to verify default compression.
Must effort is going into the documentation process in preparation for the first alpha release of the software due out either Friday or Monday. The documentation changes include full installation documentation including:
Several test cases for FTP Client have been added to verify checksum, partial and extended file copy.
(Dan Kozak)
(Phil Ehrens)
(Stuart Anderson)
(Keith Bayer)
(Igor Yakushin)
(Greg Mendell)
(Ben Johnson)
Weinstein:
Yakushin:
Shawhan:
Mandic:
I continued working on understanding the LLO-LHO coherences in S4. I observed that (uncorrelated) glitches can lead to features in the coherence plots that appear significant. I also continued studying the S4 H1-H2 coherence - by studying coherences with PEM channels I hope to identify the structures observed in the H1ASQ-H2ASQ coherence plot.
(Keith)
(Shannon)
(Christine)
(Mike)
(Veronica)
(Larry)
Mail Statistics for April 21-27, 05
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From: Ken Mason kmason@ligo.mit.edu
A BSC finite element model has been created in Algor to help explain the pier amplification and model possible solutions.
Myron has begun assembly of the spring characterization fixture supplied bt ASI. We had to order special nonstandard keenserts which were missing. I also ordered "dummy" blades of 4140 steel to test the operation of the fixture.
Thermal bars were ordered for the large and small actuators in preparation
for additional thermal studies to be done by a UROP student over the summer
From: Janeen Romie <romie_j@ligo.caltech.edu>
Working on schedule updates, project status and budgeting for our meeting with Carol and Dwight.
Checking drawings for Calum.
From: Ken mailand <kmailand@ligo.caltech.edu>
I have worked with
We have received 4’” S.Stl. stock for the lower suspension installation arm fabrication, and one set of the roller bearing with lip seal for the pivot shaft. I've nearly finished the detailing of the component arm parts, and list of the purchased parts, bearings etc.
From: Helena Armandula <ahelena@ligo.caltech.edu>
The P.O was placed for the modular clean room, manufacturing started.
We are waiting for the last modified (changed dimensions) quote to place the
oven
From: Peter King pking@ligo.caltech.edu
Testing of the new photodetector boards was on hold as I was busy with the
electro-optic timing system measurements. However the initial prototype
testing continues. The photodetector has been running for over two months
now at over 250 mA without any problems.
From: Michael Smith <smith@ligo.caltech.edu>
I am revising the BS model by incorporating a lens element into the reaction
mass (plano-convex, with R = 9m) in front of the ITM to reduce the beam size at
the BS from 60mm to 46.7mm. This change significantly reduces the total loss of
the input beams from the power recycling and signal recycling directions with
the baseline dimensions of the BS (350mm dia, 60mm thickness). Also, the power
recycling beam position on the BS HR surface is placed at the center of the
surface; this minimizes the power loss from the signal recycling direction.
From: "Erika D'Ambrosio"
<ambrosio@ligo.caltech.edu>
I fixed the locking problem in my simulation program, now the gain factor is exactly what expected from theory, given by the mirror parameters. Moreover I used the two maps, 5008 and 5009, provided by LMA for our Mexican Hat mirrors, in my simulation of the FP cavity and I found a considerable difference in the expected beam profile due to the fact that after the corrective coating treatment, both mirrors present a slightly deviation from theoretical ideal shape which affects substantially the beam shape. This effect can be partially corrected with a mirror tilt and I calculated the tilt angles using the best interpolating plane on the differences between the ideal and the real mirror profiles in the central area. Running some simulations for the characterization of the cavity with the spherical end mirror and comparison with data collected by Marco.
I'm continuing the cavity characterization. In particular the alignment has been improved so that we collected data of the lowest Laguerre-Gauss transverse modes. I also tested PZTs and driver behavior: their correct working allowed a first scanning and the collection of the first spectra of the cavity resonances. From the g-factors point of view, our cavity is nearly-confocal and so very degenerate. It can explain, for example, the strange residual of the TEM10 that looks like a TEM22. Next step should be improving in the beam profile acquisition and in the servo lock through a transmission signal and laser modulation (Matt's suggestion) or mirror dithering lock technique, in order to "clean" the beam from cavity degeneracy locking on the peak of the Airy function.
Mesa beams are optical modes of cavities with nonspherical mirrors designed to broaden the beams impinging on the mirrors. One of their advantages over Gaussian beams is that they are less sensitive to thermal noise fluctuations, especially thermoelastic noise, because of their broad and flat distribution over the optics. They also have steep tails for minimizing diffractive losses at the optics edges and reducing sensitivity to beam centering offsets. We review the features of mesa beams and the cavities that produce them, outlining how they can improve gravitational wave interferometer sensitivity. The Advanced LIGO choice of fused silica substrates for the core optics, has changed the case for mesa beams from Thermo-Elastic Noise reduction to coating thermal noise reduction and triggered a new set of optimization studies. We present the latest data from our prototype mesa beam cavity at Caltech, aimed to test this new technology and validate its expected behavior.
Thermal noise of the test masses is one of the most important noise sources limiting the sensitivity of advanced interferometric gravitational wave detectors. The mirror’s surface thermal fluctuations are averaged according to the beam intensity profile. A large radius, flat-top beam with steep edges is expected to have better averaging properties with respect to the conventional Gaussian beam. We present direct calculations of the spectral density of thermal noise contributions from various sources (coating and substrate Brownian and thermoelastic thermal noise) for various sizes of test masses and different beam profiles. We evaluated sensitivity and “reach” improvements that can be expected from the next generation of detectors using non-Gaussian beams with Flat Top profile.
The current design for dielectric mirrors consists typically of quarter-wavelength alternating SiO2 and Ta2O5 layers. The sensitivity of Gravitational Wave interferometers is usually limited by the Thermal Noise (TN) of the mirror coating. The TN power spectral density is roughly proportional to a weighted sum of the two constituents TN-wise, the usual quarter-wavelength design, which maximizes reflectivity, does not yield the best sensitivity. We undertook a series of numerical experiments using a genetic optimization engine, seeking for a required transmissivity with minimal TN. Preliminary results showed that the Genetic Algorithm (GA) evolves toward results close to periodic half-wavelength bi-layers with a reduced fraction of Ta2O5 and an increased number of layers N. The quasi-periodic stacks determined by the GA offer small performance improvements than the corresponding fully periodic, optimized-Ta2O5 fraction, solution. We investigated the design of half-wavelength period coatings where the SiO2-Ta2O5 thickness ratio is left as a free design parameter. We obtained families of trade-off curves in the transmissivity-TN plane, for different values of N, parameterized in the Ta2O5/ SiO2 thickness ratio . For fixed transmissivity, the minimal noise corresponds to well-defined values of N. We investigated the sensitivity to random errors in the dielectric layer thicknesses.
To achieve its design performance, both present LIGO and Ad-LIGO will need an Output Mode Cleaner (OMC). Although suitable vacuum chambers (LIGO HAM) are readily available, a seismically attenuated platform to provide adequate seismic isolation of the optical table is still necessary. One of the most straightforward and cost effective solutions is a passive seismic attenuation option, derived from the SAS concept. We completed a conceptual design, fit for the LIGO HAM vacuum chambers and built prototypes of the critical components. This single-stage, passive attenuation unit, has expected performance matching the requirements set for the LIGO, and even Ad-LIGO optical tables. It is also fully compatible with the baseline active attenuation systems designed to isolate the Ad-LIGO core optics. Design parameters and initial prototype test results are presented in this talk. The system passive performance can be improved, if necessary, by implementation of an additional but simple active attenuation loop at marginal additional cost.
For additional information about this report, contact Stan Whitcomb or Phil Lindquist