Aug 17, 2008

A "Relatively" Great Outing...

Image from the PHENIX experiment

This weekend I stayed in New York and did some work on Saturday. This morning, I decided to check out a newspaper and just see what looked interesting to occupy the day. The resulting outing took me to the Summer Open House Series at the Brookhaven National Laboratory.

The event featured a tour of the Relativistic Heavy Ion Collider (RHIC). The people at the lab actually pronounce the acronym as if it were "Rick." This national research treasure is described on their Website as "a world-class scientific research facility that began operation in 2000, following 10 years of development and construction. Hundreds of physicists from around the world use RHIC to study what the universe may have looked like in the first few moments after its creation. RHIC drives two intersecting beams of gold ions head-on, in a subatomic collision. What physicists learn from these collisions may help us understand more about why the physical world works the way it does, from the smallest subatomic particles, to the largest stars."
The tour took us to the 2.6-mile main particle accelerator, as well as to the sites of two major experiments -- PHENIX (Pioneering High Energy Nuclear Interaction eXperiment) and STAR (Solenoidal Tracker At RHIC). The scale and complexity of these facilities are overwhelming.

We went underground into the tunnel that houses the accelerator. A staff physicist described the equipment, its origins, function, and purpose. He answered several questions ranging from "Is this tunnel radioactive?" to "How do you make sure no one is left in the tunnel before you activate the equipment?" We also saw a static display of a section of the "tube" that carries the ionic stream and the magnets that guide the beam. It must have been a challenging construction project, and we were informed that it was the only project in recent DOE history that was completed on time and within budget.

The experiments were both undergoing maintenance, so we were able to see their "innards." These are gigantic structures that normally surround a segment of the collider.

The facility is used to study high-energy subatomic particles. In a typical experiment, clusters of ionized gold atoms are accelerated in opposite directions to speeds of 99.995% the speed of light. They are then allowed to collide and disintegrate into thousands of subatomic fragments. The experimental equipment attempts to record the identity and paths of the constituent pieces. These are then studied by the experimenters to try to gain insight into what goes on at these energy levels and conditions. The results have surprised the researchers. The Website describes much more than I can describe here.

Needless to say, I was impressed. Almost exactly fifty years ago, I was a semi-finalist in the Westinghouse Science Talent Search as a result of my interest in the nature of subatomic particles. My project was the design of a liquid freon bubble chamber. That would have been the state-of-the-art way of observing subatomic particle tracks in 1958. Today, bubble chambers only exist in museums and memories. How times change!

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