For the past two summers, I had an easy job.  That is, easy to talk about.  Every conversation went something like:

“So, what’s your job?”

“Oh, well I’m doing research up at Westmont.  I’m working with the new telescope.”

“Oh really!  How interesting.  What are you looking at?”

“Well, this summer I’m looking at asteroid orbits by performing astrometry on CCD images.  Since the asteroid is much closer to us than the stars, it moves relative to them in successive photos looking at the same coordinates in the sky.  We take three to five images like that each night for about a week, then use those points and essentially “regress” an orbit out of them, since each set of points only corresponds to one orbit.”

“Wow, that’s interesting.  What is the goal?”

“Well once we get an orbit, we can plot it, and see how close we are to the accepted literature.  If we determine that our telescope is accurate enough, we can submit data to the Harvard Minor Planet Center and potentially get published in their circulars.  We can also do some real nice asteroid research.  There are always critical-list objects whose orbits aren’t nicely defined and need to be observed more, or we could look at Near-Earth Objects, which have the potential to cross Earth’s path.”

“Wow, how interesting!  What an intelligent and attractive physicist-to-be you are!”

I may have made that last bit up.  This summer, however, something changed.  Now I found my conversations to be more akin to:

“So, what’s your job?”

“Well, I’m working up at Westmont helping to rebuild the Cosmic Muon Detection Array that we lost in the fire.”

“Cosmic Muon Detection Array?”

“Yeah, muons are relativistic particles that are formed in the atmosphere.  The detector is a set of eight scintillator bars connected to electronics.  The bars register muon hits and based on which bars flare and where, we can tell where the muon is coming from.  Then we can trace it back to where it was formed in the atmosphere and learn about what’s out there.”

[at this point the conversation becomes a sort of choose-your-own adventure with any of the following responses possible]

“Scintillator bars?” / “Relativistic?” / *blank stare*

Then I usually tried to explain the hydrocarbon that is the material for the scintillator bars, or startedto explain a bit of relativity and how the muons make it down here, but usually by this time eyes had glossed over.  To salvage my reputation as Intelligent and Attractive Physicist-To-Be, I usually changed tactics at this point:

“Yeah, so that’s coming along.  We’re building and designing it all ourselves, too.  It’s really neat.  We’re also doing some research with the MoNA Collaboration, a group that Dr. Rogers works with at Michigan State University.”

“Oh really?  What’s that?”

“Well it’s a nuclear physics group.  MoNA stands for Modular Neutron Array, which is a similar sort of set up to our CMDA, except it registers neutron hits coming from the NSCL cyclotrons.  What happens is that they accelerate atoms in the cyclotrons and then smash them at a target.  Neutrons break off and the resulting particle is ionized.  Since it’s ionized, it has a charge and a large magnet sweeps it off to the right where it’s detected.  But since the neutrons are charge-neutral, they aren’t affected by the magnet and just go straight on through to MoNA.  We can detect them there, and again trace them and the charged particles back to the impact by conservation of momentum.  Because of that, we can reconstruct the break-up and learn about the particle, particularly how much energy it lost in the decay.  Our job in the collaboration is to distinguish between single-neutron and double-neutron events, which we do by implementing scripts we wrote in Tcl.  Based on the multiplicity of the event, we can classify it in various forms and try to analyze the hit patterns for evidence of two-neutron events.”

[possible responses now include the following]

“Tcl?” / “Multiplicity?” / “Hit patterns?”/ “Modular Neutron Array?” / “NSCL?” / “Cyclotrons?” / “Ionized?” / “Conservation of momentum?” / “I don’t understand basic physics.”

Yeah I made that last one up, but you get the idea.  Every explanation is a tree that branches off into three or four sub-explanations depending upon which definitions I need to call upon.  The “NSCL” branch often has me explaining what a superconductor is AND what a cyclotron is, then trying to show the path taken by the particle at NSCL from the smaller cyclotron to the larger one and on to the target and sweeper magnet and MoNA vault.  The “Multiplicity” branch will find me explaining that neutrons can hit any number of times inside of MoNA and based on the number of hits, we have different probabilities that the event was single- or double-neutron, explaining the different types of hit-types, and probably also making a small drawing of MoNA on a napkin.

It’s not that I don’t enjoy explaining things.  On the contrary, I would gladly talk for minutes on end about the things I do for work.  The problem is that I often get the sense that the listener isn’t really interested in learning the back story of these nuclear physics pursuits.  Not many people expect a fifteen-minute mini-lecture when they ask “So, what’s your job?”  They are expecting instead a blurb like “I’m a CPA,” something that’s short, easy to remember, and doesn’t require deep thinking.  Consequently I get very self-conscious about the time I’m taking up explaining a job that not many people care about to begin with.  Not only is the science more complex, but the nuclear physics I did this summer isn’t quite as glamorous as potentially earth-colliding asteroids.

The main reason I put off writing a “what I did this summer” essay for this blog is this very hesitation inherent in explaining.  I have sort of gone into some of my job here, but there was necessarily a lot that I left out.  A lot of it is also simply difficult to explain, even for the willing.  A great deal of my summer was spent figuring out just exactly what my job was (this may or may not have affected my usefulness in my research assistant position).  Hopefully you will have piqued enough of your interest to do some Wikipedia searching via the links provided, and will have compassion on the next scientist you ask about his or her job.  I had a great time this summer, and I’m happy to share it with you via this platform in the above form, even if it is difficult subject matter.

Alternate title idea and moral of the story: “If You Don’t Talk To Your Children About Muons, Who Will?”