Monday, April 6, 2009

Why I (Actually) Like Physics (part II)

Physics is so friggin' awesome- especially when it gives you an opportunity to go off and play in Santa Barbara for a few years and (hopefully) wait out the recession.

Physics also gives rise to sites like this:

Only physics would give people the opportunity to watch a giant blimp-like object get wheeled through a small town in Germany.

By the way, the blimp-like object in question is a major piece of the KATRIN experiment, which I will probably be a part of come this fall. The purpose of the experiment is to measure the mass of the neutrino.

The neutrino, for those of you who don't know, is an elementary particle that still remains a mystery to physicists in many ways. The fact that we still don't have a clue as to its mass at this point is evidence enough for this claim. The reason we know so little about this particle is that it only interacts via the weak force- or in other words, it hardly interacts with anything. Because a particle has to interact with something before it is detected, this makes the goal of actually detecting these things incredibly hard. There are many experiments today that tackle this immense challenge, but there's something cool about KATRIN that I'd like to mention.

You see, KATRIN will attempt to measure the mass of the neutrino, without actually detecting them!

All the experiment is really going to do is measure the energy spectrum of tritium beta decay electrons. You see, when tritium decays, it produces three products: a Helium-3 nucleus, an electron, and a neutrino. The total energy released in the decay is constant and known, and must be distributed among the three products. As we know from Einstein's mass-energy equivalence, part of this energy must be spent in the creation of the neutrino itself, which makes the distribution of electron energies dependent upon the neutrino's mass.

Of course, the experiment itself isn't THAT simple. Obtaining an energy resolution good enough for the mass range we're probing is no small task, and there is a lot of work being done to make sure all the little things are taken care of.

There's also the possibility that the experiment will produce nothing at all...

But all in all, you must agree that the whole picture is nothing but pure awesome.

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