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  • LIGO Hanford Observatory News
    line corresponds to a node of the light a place where interference of the multiple passes is destructive whereas the bright lobes correspond to the electric fields of the light interfering constructively but with opposite phases A little bit of tweaking results in a better alignment and mirabile dictu the fundamental disk like TEM 00 mode appears shown in Figure 2 at right Note the beautiful uniformity of the disk minus a few striations on the lower right and near the top which are artifacts of how the beam is extracted onto the camera monitor This fundamental mode of the mode cleaner is the one that can be coupled most efficiently from the laser beam and the one that can best be matched into the main interferometer Even as the mode cleaner was being resonated with light from the laser other crews were readying optics in one 2 km arm of the interferometer When this arm achieves resonance it will be the largest optical cavity ever lit Stay tuned Smoking Out Signals in the Control Room Contributed by Fred Raab For several months now our newsletter has focused on the huge effort of getting interferometer hardware delivered from our many manufacturers across the United States and around the world Testing this hardware to ensure quality assembling components into structures then vacuum prepping and installing the equipment requires a major effort by a great many people not to mention of coordination to keep the operation running smoothly And as with any complex system glitches can occur come integration time Bonding techniques clash with cleaning techniques A powerful tornado wipes out a contractor s factory and suddenly your parts are scattered who knows where Supercleaned metallic surfaces inadvertently form cold welds and freeze up Plus a host of other unexpected obstacles It s all in the job description of building a first ever engineering design Somewhat less picturesque but certainly at least as complex are the electronics computing and software systems that knit all this hardware into a precision scientific apparatus Pictured in Figure 1 at left is the LIGO Hanford Observatory control room as it looked in early May The control room will be the nerve center of the Observatory where scientists and engineers can monitor the heartbeats of the two interferometers that will run at Hanford These are commonly called the 4K or the 2K after the separations of the mirrors in their long arms In addition there are housekeeping functions such as monitoring and controlling dust levels as well as the lighting heating ventilation and air conditioning systems for the five experimental hall buildings and the building housing the support laboratories and offices Another big housekeeping task is controlling the vacuum system consisting of 22 room sized vacuum chambers five miles of vacuum tubing about 90 000 gallons of liquid nitrogen and more than 500 signal and control points on gauges pumps and valves A Physics Environment Monitoring PEM system draws in about 100 channels of data from seismometers

    Original URL path: http://www.ligo.caltech.edu/LIGO_web/9906news/9906han.html (2015-06-02)
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  • LIGO Livingston Observatory News
    LLO As was the case last October at the Hanford Observatory this was the first time an NSF review was conducted at the Livingston site The status of the project was summarized by LIGO Director Barry Barish shown in Figure 1 at right This was followed by detailed presentations providing an overview of progress at the two observatories The status of the detector installation and an outline of the commissioning approach comprised the first day s formal presentations After a day of intense meetings all the participants were invited to one of our favorite local customs for this time of year the Crawfish Boil For those of you who aren t native Louisianans Crawfish are small fresh water shrimps They are boiled live without a shred of pity right on the premises and then hot Cajun spices are mixed in with the boiling water To guarantee a mouth watering flavor abundant sausages are next dumped into the steaming brew When it s all cooked these delicacies are served up with boiled potatoes and corn on the cob As is evident from Figures 2 and 3 below a savorin good time was had by all Just to assure everyone that Science

    Original URL path: http://www.ligo.caltech.edu/LIGO_web/9906news/9906liv.html (2015-06-02)
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  • LIGO MIT News
    impressive range of improvements As always it was difficult to find strong drivers for interferometer design from specific sources but some generalities about the sensitivity as a function of low frequency response could be made With the sensitivity foreseeable given the state of technology it was exciting to discover that the Newtonian background and the quantum limit are important contributors to possible interferometer designs At left Lunchtime at the summit Sam Richman soon to join MIT from the BIPM Warren Johnson Louisiana State University Rai Weiss MIT and Peter Saulson Syracuse tell tall tales The second day addressed thermal noise in detail The pendulum thermal noise related to the losses in the suspension fibers can be engineered to the point of disparition by changing the geometry of the fibers from their present round cross section to a rectangular form Basically the wire can become much less stiff in the direction along the laser beam but still maintain the strength needed to support the mass In addition this change in aspect ratio causes the principal source of loss thermoelastic damping to become smaller Roughly a factor of 10 decrease in the thermal noise is thus expected a huge improvement The other source of thermal noise in the experiment is that due to the internal modes of the test masses drumhead and cylinder modes New crystalline materials are at an early stage of development and will require a long and probably expensive industrial development before their use is practical Still it is important to start early on this On the third day we discussed seismic attenuation and the associated control challenges Both passive and active servocontrolled systems were presented and the elements of the designs extracted for recombination into solutions tuned to the needs and timing of reasonable upgrades Through modeling in

    Original URL path: http://www.ligo.caltech.edu/LIGO_web/9906news/9906mit.html (2015-06-02)
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  • LIGO The Editor's Page
    Mammoth undertakings across from Caltech s Beckman Institute are in full swing The area can be seen to be constantly crawling with an army of steel helmeted workmen and rugged smoke belching tractors are rarely at rest Pedestrians and other passers by are said to be inspired by the sight of great endeavors afoot as well as with the rich aroma of damp earth upturned a scent that always announces mighty structures are on the rise Yes the premier of LIGOWorld in September 2000 is certain to be a gala and star studded affair But make no mistake this is no mere celebrity event Family fun is what we re all about Dad is sure to love being packed inside the thrilling Vacuum Chamber To Venus It s dark airless silent and stationary and a ride he won t soon forget Meanwhile Mom will have a great time shopping along the Beam Tube Promenade It s two and a half miles of tubular concrete and metal that virtually guarantees huge savings As for the little ones won t they have a blast on that white knuckler the Data Control Room of Doom Here they will be cautiously strapped into Totally Awesome swivel chairs for safety and then be presented with reams of Way Radical computer print outs which they can then begin to analyze for evidence of Too Cool coincident vibrations Warning this ride may be too intense for children under five or those without PhD s On Another Subject Entirely But further reports on our theme park will have to wait till later We have urgent subjects to disgust oops sorry to discuss so let s keep moving Last week the LIGO management those terrorizing bigwigs sent me a curt and defamatory note which I reprint below Dear Dave The LIGO Web Newsletter has become a travesty you pea brained idiot What s with you anyway Previously our little gazette was a solid chronicle of noble achievements hard science interesting bios and first rate physics But under your stewardship it has dissolved into an immature mess of silly puns low brow gags frat house hijinx and corny bombastic prose We could understand it better if you were of student age and rejoicing in your exuberance as a young adult but as you re just three years from retirement and pension we would think you might prefer to exhibit a bit more dignity Need we be more explicit Get your act together pronto Or else Love Management I trust it goes without saying that I m wholly contemptuous toward these mean spirited gripes My seniority of years is in no way relevant to my ability to be crude and sophomoric And in any case I have no intention of retiring in three years or even thirty They ll have to pry my rigor mortised fingers right off the keyboard ever to get me out Besides these jabs are only cheap shot retaliation for my subversive pranks at last week s

    Original URL path: http://www.ligo.caltech.edu/LIGO_web/9908news/9908ep.html (2015-06-02)
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  • LIGO Hanford Observatory News
    make for a pretty view but not for a simple and uniform landscape Once the LIGO arms light up starting this autumn the Gladstone team will use Eric s model to discover the correct fudge factors If the factors come out close to one then LIGO s low frequency strain data may be a useful addition to geophysics data bases However the factors emerge knowing what they are will help scientists and engineers understand how LIGO is influenced by the fundamentals of its environment Second SST Team in Development Pictured at right you see Norm Graham a teacher from Kamiakin High School which is about a half hour s drive from the Hanford 0bservatory Mr Graham is developing a second LIGO SST team that will study man made sources of noise and their influence on LIGO The LIGO interferometer can be affected by sources of vibration many miles from the observatory and the Kennewick team will fingerprint and analyze such sources as traffic patterns dam and railroad operations construction activities etc and determine their range of influence Such data will provide helpful guidance in assessing the potential impacts of future land use decisions on LIGO and possible future high tech operations in this region This summer Mr Graham has worked with the Gladstone team to develop the same basic skill set and he will recruit student team members from his high school this academic year and return with them next summer Good progress has been made toward moving the research into the high schools With help from a number of LIGO scientists and engineers the teams have gotten a data pipeline set up Software running from the LIGO control room is now streaming data from a seismometer in the corner station to a fierce number cruncher called the data monitoring tool that performs high speed reduction of the raw data and writes conveniently small data files to a web server From this point the Gladstone and Kennewick High teams can access the reduced data sets over the internet and pursue the less machine intensive but more human intensive aspects of the data analysis from their high school s computers Email and regular teleconferences will maintain the tight coordination of the research group through the school year Both high schools have promised to provide research funds matched by LIGO to an account to buy supplies software and other necessities for this phase of the research Project management plans as well as contacts with other schools have been developed with the help of weekly workshops run by educators at PNNL The first microseism trend data report is being assembled by the Gladstone team and Mr Graham is preparing a report on the influence of people walking on LIGO s 28 inch thick concrete floor that is relevant to siting an optical metrology lab at the observatory Hanford Banquet Celebrates Bake Out Success Contributed by Phil Lindquist and Bill Althouse On an elegant evening in late June LIGO s Fred Raab head of

    Original URL path: http://www.ligo.caltech.edu/LIGO_web/9908news/9908han.html (2015-06-02)
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  • LIGO Livingston Observatory News
    soft closure of the gate valves during bake out so that the O ring material is not strongly compressed should insure that the O ring material will continue to perform as intended The data acquisition and monitoring instrumentation for the bake out is now fully on line The Beam Tube is at approximately 10 7 torr and all cryopumps are running The heater blankets have all been installed and are being tested as are the main power supplies First indications are that the summer heat in Louisiana should not prevent the bake out from occurring We plan to begin the bake in the latter half of August Below Figure 3 at left shows the control racks inside the Laser Vacuum Equipment Area Next Figure 4 is an outstanding view of pre stabilized laser installation in progress The basic data collection software for the interferometer control and data acquisition system is now running Fabrication and installation of data acquisition and control racks is underway as shown in Figure 3 at left Installation of cable trays in the LVEA and end stations was also completed and cable installation is now in progress Work on the pre stabilized laser Figure 4 at right is also on going The control racks have been installed and the frequency stabilization servo is being implemented LIGO Summer Student Seminar Series Contributed by Mark Coles This summer a science seminar series was organized which was aimed specifically at our summer students The seminars were ongoing through August and covered a broad range of scientific topics Anyone interested was invited to attend although students had first priority on asking questions and on the pizza which was usually served The schedule for August was August 3 Exploding Stars Living Fast and Dying Young Professor Bob Svoboda LSU August 11 An Attitude Determination System for Balloon Astronomy Professor Dick Greenwood Louisiana Tech University August 17 Cosmology and the Critical Density of the Universe Professor Rai Weiss MIT August 18 Calculations of Non linear Optical Effects Professor Bill Parker Southeastern Louisiana University August 19 Neutrino Physics and Astrophysics Professor Barry Barish Caltech August 20 Birth of Planetary Systems Directly from Super Novae Dr Bill Brown Los Alamos National Laboratory August 24 The Potential for Sapphire Optics in LIGO Professor Steve McGuire Southern University August 31 Gravity Gradient Measurements at LLO Matt Ashman Caltech and Residual Gas Measurements During the Beam Tube Bake Out Quincy Robertson Southeastern Louisiana University Behind the Scenes at Livingston Contributed by Bonnie Wascom Summer Student Workers Matt Ashman pictured at left is one of several students working at the LIGO Livingston Observatory this summer Matt is a native of this area Baton Rouge and is presently a sophomore at Caltech in Pasadena California Here at Livingston he has been working on seismic characterization and gravity gradient noise And during the school year at Caltech Matt is majoring in physics and has been chosen to work and conduct research under a grant from the Tom Tombrello Physics II Research

    Original URL path: http://www.ligo.caltech.edu/LIGO_web/9908news/9908liv.html (2015-06-02)
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  • LIGO Caltech News
    mixtures of plenary talks chosen by the session conveners followed by a number of talks chosen again by the conveners from abstracts submitted to the conference The afternoon session of the first day was very full exquisitely organized by Kip Thorne The participants were then only too happy to partake of a reception in Dabney Gardens Tuesday was a very busy dawn to dusk day with plenary sessions reporting on the status of the world wide collection of interferometers as well as four overviews of Suspensions Noise Interferometer Configurations and Quantum Limits There was even time for a workshop on interferometer Configurations convened by Peter Fritschel and David McClelland before a very popular Poster Session in Dabney Lounge Even though Pasadena was baking beneath a heat wave the session was well attended An added inducement was the prospect of refreshments and serious discussion Wednesday was another action packed day It started with a workshop on Lasers and Optics organized by Eric Gustafson and Walter Winkler The afternoon was time for a trip to the Getty Museum We lucked out because the weather was beautiful and there was no traffic getting into the Getty We weren t done for the day though because Kip Thorne gave a beautiful Public Lecture at the Beckman Auditorium later that evening entitled Probing Black Holes and the Dark Side of the Universe with Black Holes Nine hundred forty three fortunate listeners attended and kept Kip answering questions far into the night A Laser Interferometer Space Antenna LISA Workshop organized by Karsten Danzmann and Tuck Stebbins and a Bar Antennae Workshop organized by Massimo Cerdonio and William Hamilton presented the latest work in these fields These were followed by the Conference Reception and Banquet the last major social event of the Conference held in the Athenaeum

    Original URL path: http://www.ligo.caltech.edu/LIGO_web/9908news/9908cit.html (2015-06-02)
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  • LIGO MIT News
    Vernier technique I developed while in kindergarten Seeing as the MC still had no character I decided to get in on its installation and alignment see Figure 1 above So for the next few weeks we Dan Dickerell Peter Fritschel Bill Kells Nergis Mavalvala Guido Mueller Haisheng Rong Dave Tanner and I climbed around Horizontal Access Modules HAM 7 and 8 like ants in their tunnels The long long hours put in by these people resulted in the success captured by the pictures of the laser beam shown in last month s newsletter Photo Fest Above Left From left to right Dave Tanner Dan Dickerell and Guido Mueller from in front of the west side of HAM7 Right Starving grad student demands of Peter Fritschel that he be allowed to get some lunch or he will huff and puff and blow your interferometer down Below Left Shot of the Mode Cleaner s two flat mirrors MC1 MC3 in their respective Small Optics Suspensions The large optic in the Large Optic Suspension on the right is the last Mode Matching Telescope mirror Right Inside HAM8 the Mode Cleaner s curved mirror MC2 standing proudly in front of the incredibly baffled Recycling Mirror One of the most inspiring things I witnessed this summer was the coordinated way in which things progressed at least most of the time It seemed that as soon as we would hit a snag whoever it was in the LIGO community that had the solution would just happen to show up almost as if it had been planned ahead of time Living With the Mode Cleaner Having the opportunity to spend over two months living with the Mode Cleaner see Figure 6 at right allowed me to get to work with anyone and everyone who arrived at the site looking to work on the coolest thing in town And of course the permanent site staff is excellent For fellow green students I can recommend nothing higher than getting out there as a way of learning about LIGO As of last month s newsletter brief locks of the MC were witnessed in air After pumping down the vacuum system we still saw only a meager 33 percent visibility meaning the ratio between the locked and unlocked states of the reflected laser power This is a loose indication of how much power you re getting into your cavity versus how much your shooting at it More recently we have seen more healthy amounts such as 80 90 percent To throw out a couple numbers the MC is designed to have a finesse of approximately 1500 which means that it will hold roughly 10 kW of laser power when its running at full throttle That s concentrated into a spot of about 1 7 of an inch on the mirrors One of the more spectacular windows we have of this cavity isn t a view at all but a sound provided by a pair of headphones hooked up to the output

    Original URL path: http://www.ligo.caltech.edu/LIGO_web/9908news/9908mit.html (2015-06-02)
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