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LIGO Day 2
Jan. 11th, 2005 09:28 pmDear Taxpayers,
Thank you for the Swordfish dinner. I promise I will try to find some gravitational waves. I understand that you accept gravitational waves as payment for swordfish.
Tobin
* * *
Today Adrian and I came prepared to the LIGO site, with turkey sandwiches in lunchbags. The place is far enough out from town that it's not worthwhile to drive all the way back to eat. One of the LIGO offices has a kitchen, so one could really set up camp there. In fact, I've been scouting out tent locations in case I have to come back for a longer period of time. (I tried that at CERN and was quickly picked up by CERN security; I suppose it was a little brash to set up a tent right outside the main dormitory/cafeteria, but it does seem to me to be a reasonable and adventurous way to save the Government some money...)
* * *
In the morning we set out to drive the gravel road that follows the beamline, but the snowcover looked a bit much for the little Chevy rental car. There is a little "overpass," though, over one of the arms of the interferometer so that you can drive along the other arm in the inside of the "L". From there there's a nice view of the interferometer arms stretching off into the distance. It doesn't look quite as big as I expected, but I think I might have been looking at the midpoint stations.
We found ourselves a spectrum analyser, hooked up our little "whitening board," and measured the frequency response on each of its four channels. Everything checked out perfectly, so we went and installed it at the beamline, connected up signals from the interferometer's photodiodes (navigating around two bad channels), and took spectra on the output. Everything looks good. Tomorrow we'll hunt for signals!
We also transferred 5.6 GB of data onto Adrian's laptop. In the process I got to see the on-site computing center. Fairly impressive! Everything here is SUN (and all the test equipment is Stanford Research Systems; keep in mind that SUN originally was an acronym for Stanford University Network). There's something like 10 TB of online storage (fibre channel!), 100 TB in a tape robot system, a fast internet link to Caltech, and 280 xeon CPUs in a computing cluster.
Apparently some of the signal searches are actually limited by computational resources. To look for pulsars, for instance, you have to try all the doppler shifts and some other parameters. Therefore, in the tradition of SETI@Home, there's now Einstein@home which lets your computer help search for Gravitational Waves!
Thank you for the Swordfish dinner. I promise I will try to find some gravitational waves. I understand that you accept gravitational waves as payment for swordfish.
Tobin
* * *
Today Adrian and I came prepared to the LIGO site, with turkey sandwiches in lunchbags. The place is far enough out from town that it's not worthwhile to drive all the way back to eat. One of the LIGO offices has a kitchen, so one could really set up camp there. In fact, I've been scouting out tent locations in case I have to come back for a longer period of time. (I tried that at CERN and was quickly picked up by CERN security; I suppose it was a little brash to set up a tent right outside the main dormitory/cafeteria, but it does seem to me to be a reasonable and adventurous way to save the Government some money...)
* * *
In the morning we set out to drive the gravel road that follows the beamline, but the snowcover looked a bit much for the little Chevy rental car. There is a little "overpass," though, over one of the arms of the interferometer so that you can drive along the other arm in the inside of the "L". From there there's a nice view of the interferometer arms stretching off into the distance. It doesn't look quite as big as I expected, but I think I might have been looking at the midpoint stations.
We found ourselves a spectrum analyser, hooked up our little "whitening board," and measured the frequency response on each of its four channels. Everything checked out perfectly, so we went and installed it at the beamline, connected up signals from the interferometer's photodiodes (navigating around two bad channels), and took spectra on the output. Everything looks good. Tomorrow we'll hunt for signals!
We also transferred 5.6 GB of data onto Adrian's laptop. In the process I got to see the on-site computing center. Fairly impressive! Everything here is SUN (and all the test equipment is Stanford Research Systems; keep in mind that SUN originally was an acronym for Stanford University Network). There's something like 10 TB of online storage (fibre channel!), 100 TB in a tape robot system, a fast internet link to Caltech, and 280 xeon CPUs in a computing cluster.
Apparently some of the signal searches are actually limited by computational resources. To look for pulsars, for instance, you have to try all the doppler shifts and some other parameters. Therefore, in the tradition of SETI@Home, there's now Einstein@home which lets your computer help search for Gravitational Waves!
