Friday, March 28, 2014

Science Post: CosRay

It's time for another post about some of the science I look after down here at McMurdo. CosRay is probably one of the coolest projects I work with. It doesn't actually require much in the way of support from me, but between the actual science that it does, the building that it is in, and the history behind it, it is very cool.
Anyways, CosRay is one of the longest running projects in Antarctica, having run continuously since 1960, with another very short run in 1958-59 during the International Geophysical Year. The CosRay Observatory is a cosmic ray detector. Cosmic rays are basically high energy subatomic particles that are produced by processes in the sun, or by further away things, like supernovas. So, these cosmic rays cruise towards Earth at nearly the speed of light, and when they hit the atmosphere, they are destroyed, producing a cascade of secondary subatomic particles. CosRay detects the neutron portion of these cascades.


A cosmic ray interacts with Earth's atmosphere on the wall of the CosRay building.
 By counting the number of neutrons that hit the detectors, the group is able to determine how many cosmic rays arrive at the Earth's atmosphere in a corresponding location.
McMurdo CosRay is part of a network of twelve observatories that make up an international monitoring network called Spaceship Earth. By studying solar activity, scientist are able to predict when major disturbances from the Sun might occur. The longevity of the study gives information about the solar cycle, which is 22 years long. The Sun switches polarity every 11 years, and at the middle of each 11 years reaches a solar maximum, which is when many sunspots and solar flares are observed. At these times, solar "storms" are most likely to cause problems here on Earth. For example, in 2003 a large magnetic storm affected 47 satellites, including one scientific satellite costing several hundred million dollars, and which was written off as a total loss.
A detector bank

One end of one of the detectors
The neutron counter at McMurdo consists of 18 tubes, arranged in three banks of six detectors each. Each detectors case is a 7-inch stainless steel case seven feet long and maintained at -2800V. The tubes contain boron triflouride (BF3) gas doped with boron-10, which is good at capturing low energy neutrons. Each tube is surrounded by a polyethylene sleeve surrounded by lead rings. The lead rings act as 'producers' because they will emit neutrons in response to a neutron hit. As the neutrons make their way into the detector, they will get close to a boron-10 nucleus and be absorbed. The boron nucleus then undergoes fission, producing electrons, which are accelerated by the voltage differential in the tube towards the counter.

Once upon a time CosRay required a lot more support than it does today, and there was a time when people more or less lived at the CosRay building. All that time spent there shows, since the interior has been elaborately decorated.
A rainbow ceiling

The New Cos-Ray

The reason the project exists

Snowscape

More rainbows
 Between the decoration and some of the old equipment, this building is one of the coolest on station.
An old "computer" counter. There is a corresponding "bit" bucket in the corner, holding all the paper punches this machine produced.


With all the advances in computers, CosRay doesn't need that much support anymore. I check on things once a week, and run out there whenever the router that controls data transmission goes out (which seems to happen at least once a week).

At this point, the plan for the project is to move it from McMurdo to the Korean base located at the same latitude, but about 300 miles down the coast. The initial move had been planned for this year, but the shutdown caused that to be delayed, so next year, two of the detector banks will move out, while the third remains here at McMurdo to collect data. Once the other two are set up at the Korean base, the third will leave here, and the CosRay building will be torn down. Kind of sad, but the program wants to start consolidating buildings, and tearing down older outlaying buildings is an easy start to that.



In other new, penguins are starting to arrive on station. The other night I went for a ski with Beth on the road to Pegasus and we ran into this fellow at Mile 2:

That is a molting Emperor penguin, so it will probably hang around the area for a couple of week. Hopefully the Adelies will start making their way toward McMurdo soon, because those guys are supposed to be funny to watch.

And New Years was great. The tradition at McMurdo is a chili cook-off and IceStock, a music fest of bands made on the Ice.


The line-up for the night

Watching one of the bands
 It is really amazing how talented the people down here are, and the music was amazing, as was the night. And the next day we had beautiful weather and a group of us hike out to Castle Rock for a picnic and nap. Great way to start 2014.








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