How big around is the tunnel at Jefferson Lab and what do you do in it?
The tunnel at Jefferson Lab is made of two straight sections joined by a pair of arcs that sort of looks like a flattened oval if you fly over our site in an airplane. The tunnel is 7/8 of a mile around. The inside of the tunnel is concrete and is approximately 12 feet wide and 10 feet high. The tunnel is 25 feet underground. It is actually two linear accelerators linked by arcs at the ends. There is also a web-based tour of the accelerator that you might find entertaining.
What we do in the tunnel could fill several books, but I'll try to answer so you can understand more quickly. Jefferson Lab is a physics research laboratory. It was built by Southeastern Universities Research Association (SURA) for the United States Department of Energy. The main purpose of the Lab is to provide a facility where scientists from all over the world can study the nucleus of the atom. At Jefferson Lab we accelerate electrons at high speeds in the tunnel for several laps. The electrons are then directed to one of three Experimental Halls. If you drive past the Lab here in Newport News, Virginia, you can see the tops of the Experimental Halls through the trees just off of Jefferson Avenue. In each of the Experimental Halls the electron is steered to hit a specific target. The electrons deflect off of the nucleus or knock a piece of the nucleus out. Very large and complex instruments called particle detectors tell us what path the electrons take after deflection.
By studying experiments like the one described above and many more like it, physicists can learn about the make-up of matter. Jefferson Lab conducts research that aims to discover what the universe is made of and what holds it all together.
Knowing more inspires humans to want to know more. It is that curiosity that makes us all human.
Brian Kross, Chief Detector Engineer (Other answers by Brian Kross)