j_one_k

So there's this section of the caves where we don't go. The official reason is because there's a vibration-sensitive geology experiment back there. We all know the real reason has to be more ominous...

Detecting dark matter, at least with our approach, begins with setting up a very generic particle detector. In our case, it's a tank of liquid with light sensors trained on it. Any energetic particle that comes in can hit the liquid, which will produce a small flash of light, which the sensor detect. Now we know that something just happened. Is it dark matter?

The main way we tell if an event was dark matter is by eliminating the chance it was anything else. This is why reducing backgrounds is so important. We reduce the number of light flashes from everything that isn't dark matter by: * building everything out of ultra-pure non radioactive materials * putting the experiment underground * keeping everything very clean, so no radioactive dirt gets inside.

We still have some backgrounds left. So, we analyze the timing of the light flashes, and look for simultaneous light flashes in background detectors placed around the dark matter detector. With these methods, we can catch and ignore all of the remaining background signals. The only thing that should be left is dark matter.

So, if we see anything that doesn't look like a background, we have to conclude that it's dark matter. We've spend years (most of my PhD time, in fact) convincing ourselves that we will be able to eliminate or catch every background so nothing but dark matter will be left.

How tedious is my job? Better than most, I think. There's definitely times where I'll spend a few 12 hour days in a row just operating a simple piece of machinery or putting screws in a million light sensors, but there are also days when everything comes together and I get to see some exciting results. Most of my job is coding, and is probably like many coding jobs.

How'd I get my job? I applied to graduate school right after college. My grades were ok, my test scores were fine, and I had a pretty full resume of undergraduate research experience. That last part is definitely the most important part to getting into PhD programs.

Unfortunately, all the volcano bases we looked at had problems with secret agent infestations.

There's a rather kickass wired connection to the surface. Speeds here are great, because they've invested a lot into a serious net connection make transferring large amounts of data not too painful.

Edit: Wow, this is like the #1 most frequently asked question in this thread.

When any particle hits our liquid, it transfers a small amount of energy into the liquid. That energy goes into exciting the electrons in the atoms of the liquid at the point of impact. Those electrons will eventually release that energy, and go back to their usual orbits. They release the energy by emitting light.

This goes for any energetic particle, and in most liquids (and most solids). Ordinary water does this, and we use water for the biggest background detecting layer (because using more exotic liquids with better light emission would be too expensive to have many tons).