About IceCube

It's been a little over a week and the routines are settling in somewhat. So what do we do? Well, we are here to build a neutrino detector. Neutrinos are subatmic particles that almost never interact with normal matter. The most natural question at this point is: "why do we care?" One of the more interesting applications is as a telescope. Visible light is easily blocked by inconveniently placed dust clouds or other objects in the universe. In addition, strong electromagnetic fields distort the paths of many particles making it difficult or impossible to determine the location of the source.

Neutrinos, on the other hand, will pass through these cosmic obstacles and you can trace their origins by bascally reconstructing a straight line. This is very neat, but it presents certain practical difficulties. After all, if these things don't interact with normal matter very often how do you detect them. Well, in fact we never detect them directly; we detect a particle called a muon which is the result of a neutrino interacting with normal matter. But given that this seldom happens, you need to watch a lot of matter in order to see even a few of these interactions.

The IceCube detector, when completed, will effectively watch one cubic kilometer of ice. The ice at the south pole is very clear and very dark. This makes it ideal for detecting the light pulses given off when an interaction happens. So to detect this, we use very sensitive light detectors (photo multiplier tubes) attached to cables which are lowered into deep holes in the ice. The holes are drilled 2500 meters deep using hot water. When the hole is complete, the drill is pulled back to the surface and the cable with the light detectors is lowered into the hole. There they are left to freeze into the ice where they spend their useful lives reporting on tiny little flashes of light.

This requires a fairly large logistics operation. This year, we will move approximately 600,000 pounds of cargo to the south pole. To date we have moved approximately 3.8 million pounds of cargo to the pole. This obviously requires a lot of planning, but happily, we have quite a bit of time to do that. It's really only possible to get planes to the pole starting around late October and ending in early March. After that, the sun sets and getting in or out becomes basically impossible. So we spend the winter (our summer in the north) working out all of the logistics and planning everything as well as possible.

Then in late October, it's go time. The sun rises, and we're on the clock. The drilling won't start until the beginning of December. First, we have to dig out, get power and heating hooked back up, and get all of the equipment basically rebuilt after having been broken down and stored for the winter. This involes moving a large amount of snow, a number of buildings, and lots of odds and ends.

It also involves getting the people and new cargo in, and that can be a real problem. This year we have had many flight delays which have stranded people and cargo for days. This is built into the schedule somewhat, but we are using all of the wiggle room we have this year. We try to work the plan with the people we've got as best we can. That means you get to try new things all the time. In this case, perfection isn't the important thing, keeping things roughly on schedule is. In my case, it meant working on getting one of our testing facilities set up while our experts were stuck in Christchurch. There were a couple of us working on it, and at least one of the guys was roughly familiar with the setup, but we got a couple things wrong. Fortunately, nothing serious. And we're only a day behind now, which means we're OK.