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  • LIGO Livingston Observatory News
    demobilization following the bakeout The successful completion of this task represents the fruition of about two years of planning and more than one year of intense on site activity Table 1 below lists the summary results achieved for each module Congratulations to all associated with this important program Installation Activities Forge Ahead Contributed by Mark Coles An important focus of activity here at the Livingston Observatory has been the installation and commissioning of the interferometer itself The pre stabilized laser PSL which has been operating since mid 1999 was studied in detail as the various servo systems designed to control its performance were characterized The frequency and intensity stabilization servos have been installed and well characterized The pre mode cleaner was observed to have the same barometric sensitivity as the one at LHO It has now been replaced by a new sealed unit The mode cleaner optics and associated electronics have been installed and its operation has been integrated with the PSL Diagonalization of the suspension servos meaning the process whereby the mirror motions are decomposed into motions that are pure pitch roll yaw and displacements remains to be completed The glue joint of one mirror magnet was found to be defective and the position adjusting magnets used on the small optics only at LLO were observed to directly couple seismic motion into the mirrors making the system unexpectedly noisy This summer all of the small optics suspensions were removed inspected and rehung The position adjustment magnets which were added to the small optics to increase the adjustment range of the electromagnetic actuators were removed They remain in place on the large optics at both LLO and LHO where the much larger mass of the large optics reduces the seismically induced displacement noise The diagonalization work will be revisited this fall Another important activity associated with the mode cleaner commissioning was a measurement of the frequency noise of the laser system using the mode cleaner cavity as a frequency reference It was discovered that acoustic noise was readily coupling through the mirror mounts on the PSL optical table into the light itself Joe Kovalik made systematic measurements of the acoustic sensitivity of each of the mirror mounts The mounts were then replaced with much more robust custom mounts These mounts shown in the photo at right do not use a slender post to support the magnet but instead integrate the mirror into a squat aluminum brick which has very high resonant frequencies relative to the gravity wave band During the next pumpdown cycle expected this fall the acoustic sensitivity of the new robust system will be investigated This summer installation of all of the large optics was completed as seen in the first photo below Alignment of the optics is now in progress and should conclude this month Also installation of all of the core optics support components baffles beam pick offs telescopes etc is nearly complete mid and right photos and will also conclude this month We are working

    Original URL path: http://www.ligo.caltech.edu/LIGO_web/0008news/0008liv.html (2015-06-02)
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  • LIGO Caltech News
    Science speakers to sign on the dotted line so we can include their talks in the proposed book Well in advance turned out to be a few months but better late than never Wait wait wait let s start a scholarship fund And let s pay for everything by putting together a popular book But one last thing shouldn t we tell Kip Below Left to right Kip with Eanna Flanagan Kip again with sisters Sandra and Barrie the song stylings of the Gravitones Laying the Trap The most FA d Q about Kipfest is how we got the honoree himself to agree to it The answer is through sheer diabolical cunning The crafty disorganizers first spent six months arranging enough of the event s infrastructure so that Kip s refusal would have caused great embarrassment to the organizing committee During all this Kip was kept blissfully unaware I even conspired with Kip s secretary Shirley Hampton to make sure no trips were planned on the days in question and that those dates be kept clear at all costs Kip suspected there would be SOME kind of recognition of his 60th birthday but he never imagined the scope the Chanteuse the budget or the assorted surprises Next the disorganizers completely unburdened by any sense of shame notified Kip of the plans using a mixture of dishonesty and psychological disorientation patterned on Caltech oral exams A false web page was prepared announcing Kipfest but leaving out a few details In fact leaving out all the details At a pre appointed time co conspirator Carolee Winstein who is also Kip s wife showed her husband the false webpage just at the moment a conference call came in for him from Richard Price and Sandor Kovacs Carolee went to another extension and everyone began talking at once making it impossible for Kip to say very much again modeled after Caltech oral exams After a 15 minute hurricane of bewildering chatter the call was over and Kip was informed he had just agreed to the Fest We needed to contact others as well Not only did we want scientific colleagues from Kip s life to join us for the banquet Friday night but we wanted friends from his youth and family members Getting in touch with one man in particular Kip s high school debate partner proved somewhat complicated Kip s debate partner had gone to Utah State University in Logan Utah my alma mater and also the university where both Kip s parents taught First I tried to locate him through the USU alumni directory No luck Then I tried locating him on the web What I found was his agent s address and phone number Well that might have to do I thought but let s try one other avenue I called my mom in Logan who called Kip s mom who called the debate partner s mom who put me in touch with the man himself Merlin Olsen FTD spokesman former

    Original URL path: http://www.ligo.caltech.edu/LIGO_web/0008news/0008cit.html (2015-06-02)
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  • LIGO MIT News
    be relatively stiff making the system fairly easy to work with and a robust platform from which to hang the exquisite optics The combination of two such tables stacked together will reduce ground vibrations at 10 cycles second by a factor of a few thousand fulfilling one of many conditions to allow LIGO II to detect gravitational waves at that frequency A group of researchers called the stiffs the moniker derives from the aforementioned stiff mounting springs any resemblance to corpses tramps flops etc is purely coincidental from JILA Louisiana State University MIT and Stanford have been developing this particular isolation strategy for LIGO II One major focus of the work to date has been the construction and testing of a two stage prototype system This device went from a sketch on a white board in December 1999 to installation in a vacuum tank at LIGO MIT in March 2000 The detailed design and fabrication were performed at High Precision Devices in Boulder Colorado in close coordination with the JILA people The components were shipped to MIT where in the course of a whirlwind few days they were assembled on the high bay floor and the completed prototype was hoisted into one of the chambers formerly occupied by part of the Phase Noise Interferometer Jamie Rollins a graduate student at MIT is shown in the photo at left guiding the prototype into place The support structure enveloping the two isolation tables is being carried by the yellow lifting straps The rectangular and disc shapes attached to the sides of the tables are ballast mass used for simulation of a payload and adjustment of spring positions and level For reliability and ease of use the prototype is instrumented with commercial forcers and sensors The dull green domed cylinder on the corner

    Original URL path: http://www.ligo.caltech.edu/LIGO_web/0008news/0008mit.html (2015-06-02)
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  • LIGO Hanford Observatory News
    laser beams to vary by about 1 1000 th of the diameter of a proton or less than 1 10 000 000 000 000 th the diameter of a human hair This change ultimately is read out by monitoring the interference of the laser beams at a beam splitter hence the name interferometer with sensitive photodetectors Eventually this produces a voiceprint that can be analyzed by computers or played out on headphones Imagine yourself listening to these headphones A gravitational wave might sound similar to the songs sung by whales amid a background of sounds generated by the vibrating atoms in the mirrors and suspension fibers as well as the noise of light photons interfering at the beam splitter Proper design of the mirror surfaces optical coatings and the attached hardware is essential to keep that background noise from drowning out the faint whispers of gravitational waves generated in deep space The mirror itself is a 10 diameter by 4 thick piece of ultra pure synthetic fused silica The purplish coating is the mirror surface a multilayer stack of alternating dielectric materials that is highly reflective to infrared light from our lasers Getting good interference and keeping high power light beams trapped between the interferometer mirrors requires that the mirror surfaces and coatings be shaped accurately and uniformly to about a millionth of a millimeter Reflection losses due to the absorption and scattering of light are measured in parts per million necessitating extreme caution to prevent exposure of mirrors to dust and hydrocarbon vapors The mechanical design criteria for this mirror and its attachments to best manage the noise produced by vibrating atoms in these structures was the subject of a Ph D thesis by Aaron Gillespie a thesis built on research done over many decades in many countries As

    Original URL path: http://www.ligo.caltech.edu/LIGO_web/9901news/9901han.html (2015-06-02)
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  • LIGO Livingston Observatory News
    spectra in the laser and vacuum equipment area LVEA using a calibrated sound meter a seismometer accelerometers a tilt sensor and induction coils As part of these measurements we switched off various components of the building s HVAC system and made quiet measurements during the late evening hours Fortunately the spectra we have measured seem generally to satisfy our criteria The Winter Holidays followed shortly after these initial measurements allowing an excellent opportunity for further studies in the LVEA and also in the end stations We arranged with two high school students Tomyka Crier and Millicent Schmidt to participate in these further measurements during the week between Christmas and New Year s Day We had a lot of fun taking the data during a very quiet period and observing such features as the fluctuation in the micro seismic peak and also in the discovery that the magnetic field environment in the LVEA is about an order of magnitude more intense there than in the south end station It was also quite impressive to work with two very smart students who had never heard about Fourier Analysis on their first day yet by the third day were expert users of a Hewlett Packard Dynamic Signal Analyzer How many high school students can say I spent my Christmas vacation making power spectral density measurements and be able to explain it too Figure 1 at left above reveals the vertical displacement spectrum measured at the south end station on December 30 The red line is the LIGO Standard Spectrum The displacement spectrum measured exceeds the standard spectrum for frequencies below about 5 Hz but is actually of somewhat less amplitude than measurements made at the same location by Rick Savage and Alan Rohay on October 30 1995 before the building was built It is interesting to note that at frequencies above about 5 Hz the effects of the HVAC system are readily observable Below that frequency there are some peculiarities to the data that are probably the result of other episodic contributions to the noise spectrum i e the background is not very stable Otherwise it is difficult to understand why the building should be noisier when the air handlers were turned off Next Figure 2 at right shows the difference between the magnetic field environments in the LVEA and the south end station VEA We were surprised to find that the magnetic field intensity is more than an order of magnitude larger in the LVEA than it is in the south end station VEA The reason why is presently a mystery We also noted quite a bit of variability in the magnetic field environment as we did when measuring the seismic environment The overall shape of the spectrum fluctuates somewhat The two students who assisted with these measurements Tomyka and Millicent both attend the Louisiana School for Math Science and the Arts LSMSA located in Natchitoches which is rather amazingly pronounced Nak uh tish by the cognoscenti The physics faculty of this

    Original URL path: http://www.ligo.caltech.edu/LIGO_web/9901news/9901liv.html (2015-06-02)
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  • LIGO Caltech News
    gravitational wave detectors and foster research and development of new technology Represent the gravitational wave detection community internationally acting as its advocate Provide a forum for the laboratory directors to regularly meet discuss and plan jointly the operations and direction of their laboratories and experimental gravitational wave physics generally GWIC s membership includes representatives of all the interferometer detector projects ACIGA GEO LIGO TAMA and VIRGO acoustic detector projects ALLEGRO AURIGA EXPLORER NAUTILUS and NIOBE and space based detector projects LISA LIGO Director Barry Barish and I attended the third of these twice yearly meetings this one held in Paris on December 19 1998 It was a very robust affair Representatives of several of the national agencies responsible for funding the various efforts attended presenting their current agency programs and their views on the international aspects of the field They suggested areas where GWIC acting as a body might provide assistance and advice to help them in guiding their programs Represented were the United Kingdom s Particle Physics and Astronomy Research Council PPARC the US National Science Foundation NSF the appropriate part of the German Max Planck Institute MPI Italy s Istituto Nazionale di Fisica Nucleare INFN and the French Centre National de la Recherche Scientifique CNRS This was quite a significant gathering and presages clear communication of research priorities and emerging collaborative ideas between the scientific teams and their support agencies The several interferometer teams reported their status By all accounts 1999 promises to be a remarkable year with the Japanese TAMA project commissioning its 300 meter interferometer and with quite advanced construction and installation going on in GEO 600 VIRGO and LIGO New plans are being launched also in Australia by ACIGA Above At left Masa Katsu Fujimoto describes the exciting progress in commissioning TAMA Next Bernard Whiting recounts the program in Australia When The Scientists Become The Studied One presentation offered a unique twist Even as the scientists prepare to listen to the heavens the scientists themselves are being focused on as objects of study Harry Collins of the Centre for the Study of Knowledge Expertise and Science at Cardiff University in the United Kingdom reported to GWIC on his sociological study of the gravitational wave community Harry has been lurking in the shadows of almost every significant meeting on gravitational wave research for several years His report was an opportunity for us all to hear from this fly on the wall observer His talk was most interesting and we will devote a special column in next month s newsletter to an article by Harry We cannot pass up the opportunity to return the favor and find out a little something about him In the meantime interested readers can check out Harry s website by clicking here Returning to the events of this latest GWIC meeting the plans for LISA a space based interferometer were described This ambitious project is now the subject of consideration in both the US and Europe Undisturbed by the gravitational field from

    Original URL path: http://www.ligo.caltech.edu/LIGO_web/9901news/9901cit.html (2015-06-02)
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  • LIGO MIT News
    was usually around 7am Pacific after a pedal to the metal drive across the mountains from the desert We decided that at worst it would be a small increment in the contract with CB I to ask them to hold the equivalent of an automobile head lamp at the center of one end of a 2km module while Larry and I looked down the tube from the other end By the middle of that California morning it had been established that CB I was willing to carry out the test free of charge and it was all arranged for the June 1998 CB I LIGO monthly meeting at Livingston So shortly before 8am just before the monthly meeting Larry and I dressed in the protective bunny suits gazed intently into the blackness of the Beam Tube for Dennis Dickenson and Steve Hand of CB I to turn on the light We both saw it at once The light was centered horizontally but was about a foot low in the vertical direction in the tube The thought that the Beam Tube could have been this much out of alignment was clearly unacceptable but then this kind of discovery was the basis for performing the test in the first place When an issue really matters one s mind can shift into high gear real fast even without the fuel of coffee One immediately begins to sift through the various phenomena that one should have thought of but had neglected or forgotten about In less than a minute we decided it was a pretty good bet that what we were experiencing was either vertical thermal gradients meaning that hot air rises and is thinner or the nonuniform atmosphere which cause a change in pressure with height It turns out that it was both effects which had been at work and had the thermal gradients been even larger we would not have been able to see the light at all Instead of exiting the tube a foot low after 2km it could have been a bigger effect and the light beam would never have been seen at the exit I don t really want to contemplate the drama of that eventuality but our first thought would probably have been that CB I had left a purge dam in the finished Beam Tube And in our high state of dismay we might have acted on that premise The night time worrying would then have really caused some mischief Just recently at the end of December after the bakeout of the Y1 module in Hanford Mark Lubinski Mark Guenther Larry Garrelts and I tried this observation all over again This time the module was pumped out and we used some glass observation ports that had been installed at the ends of the module at Mike Zucker s instruction for the serious business of interferometer alignment Larry held a light at one end and Mark L and I had a look from the other end The light

    Original URL path: http://www.ligo.caltech.edu/LIGO_web/9901news/9901mit.html (2015-06-02)
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  • LIGO The Editor's Page
    MIT this month is a reprint a good reprint but a reprint nonetheless Do all these anomalies require an explanation Probably Let s zip over to the LIGO Web Newsletter FAQ and see if we can find some answers there The LIGO Web Newsletter FAQ Q What is the LIGO Web Newsletter A The LIGO Web Newsletter is a mammoth journalistic enterprise with bureaus in New York Rome London San Francisco Brazil and with an annual operating budget of over ten billion dollars Staffed by a dedicated army of over 25 000 hard working men and women it makes CNN look like a kindergarten by comparison Day and night our reporters roam the planet like bloodhounds sniffing out a jail house fugitive relentlessly pursuing any lead any scoop any trace of news that might be of value to you our loyal LIGO readers Q Is this true A No Of course not Idiot Don t be so naive Q I ve never been insulted by a website s FAQ before Is this customary A Statistics on this subject are rare but a team of number crunchers working out of Harvard has adduced ample evidence to suggest that online incidents of derision derogation vituperation and pejorification are increasing Experts cite the growing incivility in all facets of everyday life to account for this Q I know it s true People are so rude especially in their cars A Please phrase your comments in the form of a question Q Sorry A This is a FAQ after all Q Sorry A Moron Q Sorry So anyway what s the deal with the LIGO Web Newsletter Why all the unconventionality this month A Unconventionality can be a strength It signals power vitality independence of mind and conviction in purpose Q And this is

    Original URL path: http://www.ligo.caltech.edu/LIGO_web/9902news/9902ep.html (2015-06-02)
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