Saturday, March 5, 2011

Beamtime, lovely beamtime

I mention beamlines, beamtime, and all things having to do with beams constantly. I suppose it would be good to clarify what the hell I am talking about…
I work in a synchrotron. It is a grandson of the cyclotron, which was a circular particle accelerator and collider.  Synchrotrons became useful because of the revelation  that electrons produce electromagnetic radiation when they are made to turn a  corner.  This radial deceleration results in energy lost in the form of light.  I recommend you read herehere and here to learn more about synchrotrons, because I am a chemist, not a physicist and am therefore not the best reference.

It was a grad student who actually observed this with his eyes. Poor guy!

 Synchrotrons run on a 24hr/7day a week schedule. Electrons are constantly being accelerated and  shoved out into the storage ring, to do their job of cornering, losing energy, and producing photons.  Preferably X-ray photons.
This is where the beamlines come in. Beamlines are how the light gets from the synchrotron to the experimental sample. With UV, vacuum UV and Soft X-rays, the beamline is usually under high vacuum, and includes focusing  and monochromating optics of many types. In the case of X-rays, the beamline is also what keeps the X-rays from irradiating you, with selective placement of lead.  The beamline I use is a hard X-ray beamline, so there is a lead-lined shed at the end, called a hutch. Inside the hutch is where the magic happens. Probably a whole other post.  During my beamtime, my world revolves around a lead lined shed and it’s expensive contents, a microscope, a couple computers and somebody else’s potentially very interesting, but probably infuriating samples. What more could I want, right?
So flash back to this week: I currently have two collaborators who are on my back for results (NOW!!!!).  So what did I do this week? What did I accomplish? I collected data, and helped others collect data. I have spent the majority of the last week sitting at a desk surrounded by the bedlam hum of mechanical work.  I can tell the difference between a turbo pump spinning and a roughing pump coughing.  I can hear undulator gaps changing.  Can I hear my phone ringing? No. The cacophony of a synchrotron is an unbelievable assault on your aural system. At times, you are sure there is music, lurking in the background, on the edge of your strained hearing, but it is really just the motors driving the pitch of that monochromator behind your desk.
On Friday, after spending the majority of the last week on the beamline, I walked out of the building, and ambled towards my car. The soft light of the late afternoon fell on a hushed lab left vacant by fresh snows in the mountains. A flock of juvenile turkeys pecked and scratched at  damp soil under fragrant eucalypts. The peace was revitalizing; having a new lease on life, I drove home to see the horses.


  1. So funny... I know exactly what you are talking about to the tee. rough pump, turbo pump, music in your head. I still hum to myself at almost every moment of deep concentration and inappropriately in meetings. A result of endless nights of beam time. Its a totally different world. Thanks for sharing.

  2. Dude... I know nothing about physics... or chemistry... but I DID work a temp job transcribing for National Electrostatics Corp in Wisconsin for a few months in 2003... I learned a lot of big words helping them get their contracts for particle accelerators on paper/into the computer. Weird bunch of scientists I worked with, too... like you dredged the bottom of the physics department to find them...