Dr. Elena Long
  A liquid helium level sensor is placed inside the superconducting magnet's cryostat to ensure that the solenoid stays at 4 K.  

Fig. 1 - Dr. Long installing the solenoid for UNH's new DNP polarizer.



Fig. 2 - Projected uncertainties for the Azz experiment.

Azz for a Six-Year-Old

Recently, a six-year-old asked me about my recently-approved Azz experiment. Below is roughly what I told him.

For a long time, we thought we knew more-or-less what goes on inside of atoms. Protons pushed away from each other, and neutrons hold them together. When they move, they move like going through a big blob that's the same all over. For the most part, that worked really well. There were a few weird things that we didn't understand, but we thought we had a good grip on what happens.

That changed about 8 years ago. Scientists found that one out of five times, two pieces would get really really close together and move really really fast, and when you bump something into them they fly off in opposite directions really fast! Not only that, but when it happens the two pieces are almost always a proton and a neutron, almost never two protons or two neutrons. And we see this all the way from the very lightest to the very heaviest atoms, always in the same way. This was really surprising! Scientists began studying this weird thing, and now we think we have a sense of why it's happening, but we know very little about how it's happening. That's where my experiment comes in.

I'm going to use the simplest case where this happens, an atom with only one proton and only one neutron. With special equipment, I can change the shape of the proton-neutron group in such a way that it shrinks the part we already know a lot about and makes what we don't know bigger and easier to see. I'm going to set it up so that the proton-neutron is both really close together and moving really fast, just like in the weird thing, and use that to understand how the weird thing happens.

The Deuteron Tensor Structure Function b1 experiment, E12-13-011, was approved by JLab PAC40 with an A- physics rating.