What to Get a Teenager for Christmas: A DIY Muon Detector

Cosmic rays shine onto the earth every day, whether rain or shine, travelling from distant supernovae and other astrophysical events. On their way through earth's atmosphere, these rays decay into particles called muons.

Now, cosmic rays aren't just the stuff of comic books or science labs any more. Thanks to the work of a clever team at MIT, you can harness cosmic rays in the palm of your hand, with your own muon detector.

What can you do with a muon detector? In addition to starting on a lifetime path exploring the universe with science, and impressing your friends, if you had your own muon detector, you could figure out your elevation - the rate of decay means that you can calculate the altitude of your airplane or how deep the subway platform is. But that is just a start. Muon detectors have been used to discover the voids in the great pyramids in Egypt.

The muon tomography used to map voids in pyramids could in theory be used like x-ray vision to look into cave walls or buildings. Lead researcher Spencer Axani says,

"That's something I'd like to try out at some point, maybe to map out the office on the floor above me. For now I like to take these detectors in my briefcase and measure the muon rate when I'm travelling."

The MIT team invented the small, cheap detector as part of a project to add muon detectors to the IceCube observatory at the South Pole. But they realized that their detector could inspire students to explore astrophysics and advance their technical skills, so they started the outreach website CosmicWatch to explain how to build the muon detector.

The CosmicWatch site links out to GitHub - which you may already know from projects like raspberry pi -- where all the parts needed to build your own detector can be sourced. That is where the bonus entrepreneurial points come in: as far as I can see there is no 'kit' per se to be bought. This gift might best be packaged as a purchasing list and a gift certificate so that the recipient can go on a shopping spree, finding the parts at recommended vendors or around town.

Alternatively, get a local school to add these muon detectors to their program. What a great combination of building skills and provoking curiosity

Estimated build time: 4 hours for first build, 1 hour each with experience, not counting the time to acquire the parts. Estimated cost: $100 per muon detector.