January 24th, 2010
New Zealand, McMurdo and South Pole - Current Time
For the first science topic, I'll start off with some information on what is probably the largest science project going on at the South Pole at the moment. Out of are typical population of about 250 this summer, about 50 of those are people participating in the Ice Cube Project.
Ice Cube - They were one of the early season science lectures, and we had an opportunity to go out on a Sunday afternoon and take the tour.
Warning - serious distraction ahead. I won't even attempt to go into much detail, but there are plenty of details available at the Ice Cube web site.
From the Lawrence Berkeley National Laboratory web site:
IceCube is a telescope under construction at the South Pole at the US Amundsen-Scott station. It is an unusual telescope in many respects. It is buried a mile down in the Antarctic ice sheet, rather than situated at the surface. IceCube looks down, into (and through) the earth, rather than up into the sky. And finally, the "light" seen by this telescope is composed of individual fundamental particles called neutrinos. In a real sense, IceCube is opening a new window on the universe and will map the neutrino sky.
Upon completion in 2010, IceCube will consist of over 4000 sensors located in a volume of about one cubic kilometer of highly transparent ice situated between 1500 and 2500 meters below the surface. These sensors will detect the optical light emitted by other fast-moving electrically-charged particles (electrons, muons) moving upward, each of which is the result of a collision with a high-energy neutrino that penetrated the earth. IceCube will determine the directions from which the neutrinos, which have no electrical charge and practically no mass, came to us and how much energy each carried. (See the animation at the right.)This is a new kind of astronomy, one that we hope will tell us new things about our universe. For example, one of the goals of high-energy neutrino astronomy is to discover the origin of the extremely high-energy cosmic rays that bombard our earth. We believe we can use neutrinos to identify the sites in the distant universe where these cosmic rays are produced. Ice Cube is trying to detect neutrinos (a sub atomic particle), and they are not trying to capture the neutrinos that are coming directly from space (above us), but rather the neutrinos that have come from space and passed through the earth, and are on their way out at the South Pole.
I won't spend any more time on the science, but will walk you through the tour we got, and how they are building the array.
Ice Cube is located about a 1km from the station, on the far side of the skiway. Currently is looks like a large construction camp, but sometime next season it will be winding down, and the only thing above the snow will be the lab, and lots of flags marking the drill sites.
The DCC is the Drill control center, and yes it is an office built into a shipping container (MilVan). From here, they can control the drills at the drill site if necessary, and they control all of the equipment and heaters for creating the hot water used to drill the holes.
Most of the holes that they drill are only about 30" in diameter, but they are 2.5km (1.5 Miles, or 8200') deep. In order to drill that deeply, they need a lot of hot water to melt the ice. They also have to make up extra water, as the the water from the melted ice only occupys about 60% of the space the ice did. In order to do this they have their own Rod Well similar to what is used for supplying the station with water. It basicly consists of a bulb that they circulate warm water in to keep melting the snow, and then pumping the water up as needed. They try to limit the depth to avoid overwhelming the pumps ability to bring the water back to the surface.
So, then we moved onto the plumbers nightmare. These are the initial heaters for warming the water for the Rod Well, and the first stage of the water needed to drill the holes.
Then after they have the warm water, they have to presurize it. The drill operates with a pressure of 1,000 pounds per square inch (PSI), hence the need for a lot of pumps.
At this point they have luke warm water at high pressure, but they need to bring the temperature up in order to be most effective, so more boilers to heat the water.
And it takes more than a single van's worth of heaters to get it up to the high temperatures they need, so there are several buildings worth.
The high pressure high temperature water is then sent via insulated hoses to (and back) from the drill rig.
Inside we were able to see the parts of the drill rig. This portion allows them to monitor the size of the hole, the pressure, temperature, and that the pipe is still straight. They don't have anyway of steering the drill, they are dependent on gravity to keep the hole straight, and so far it's has worked.
Attached to the bottom of that is several pieces of pipe, that eventually narrows down to an outlet of 3/4 of a inch. That nozzle operates at about 1,000 psi, at 200 gallons per minute, with water that is about 80 to 90 degrees Celsius.
After several days of drilling, you end up with a hole over 8000' deep. It requires burning about 4,300 gallons of diesel fuel to heat the water and run the pumps for each hole.
They had just finished installing the sensors in this hole about 8 hours before we got there. The cable to all the sensors is what is hanging down the hole. It's about 1.5km to the start of the sensor array when then runs for a kilometer below that. Nothing goes down the hole except the sensors, and additional water to fill the hole.
I believe they completed 20 holes and strings of detectors this season, and have another 16 to do next austral summer and the original design will be complete.
Much of the detail on how it's all done, and what they are seeing is on the web page I mentioned above the Ice Cube web site.