News By Location

In the last year, the polarization of CEBAF's electron beam has increased by more than 10 percent to over 86 percent polarization. This vast improvement in polarization, or the percentage of electrons spinning in one direction, has reduced the amount of beam time needed to complete precision experiments like G-Zero and HAPPEx. It's the result of work by the Electron Gun Group, which has spent the last two years pushing the boundaries of photocathode physics.

Unlike a regular computer -- whose "brain" consists of one or perhaps two processors -- a cluster computer's brain can contain hundreds or even thousands of individual processors, called nodes -- all wired together. To solve a problem, the cluster splits the problem into parts, and each node computes its designated part and shares the result with other nodes to produce the final solution.

In scattering experiments, the momentum transferred to a nucleon target from the incident electron is a primary characteristic of the interaction. Large momentum transfer reactions probe the fundamental quarks and gluons (collectively known as partons) that make up the nucleon.

In 1827, Robert Brown observed that pollen grains floating in a drop of water jiggled constantly. The phenomenon became known as Brownian motion. Over 75 years later, Einstein proposed that the pollen grains were being jostled by the molecules of water. The impurity (pollen grains) Brown had added to the water allowed Einstein to deduce the presence of individual water molecules and describe at least one of their properties.

Spin is an essential and fascinating phenomenon in the physics of elementary particles. Spin was first defined by Goudsmit and Uhlenbech in 1925, and has played a dramatic role in elementary particle physics, sometimes refuting theories and at other times supporting them. During Experiment E99-117 at Jefferson Lab, an international collaboration collected precision data on the spin of the neutron. Results from this experiment provide evidence that our current understanding of spin is not totally valid.

College of William & Mary (CWM) scientists have found that an equivalent dose of potassium iodide five times higher than the FDA-recommended dose for humans, in the event of a nuclear accident, is needed to protect small animals effectively from radioactive iodide in medical imaging procedures. This study was performed as part of a long-term animal nuclear imaging project conducted by of biology, physics and applied science researchers from CWM and Jefferson Lab.

How do quarks and gluons, the elementary constituents of all matter, combine to form the protons and neutrons in the nucleus of the atom? This is a fundamental unsolved question in nuclear physics that researchers at Jefferson Lab are working to answer. The internal structure of the proton has been studied for several decades, and scientists have learned a great deal. However, much less is known about the structure of the neutron.

Just as a top spins on a table, the tiny quarks inside protons and neutrons also spin. Now a complex calculation by theoretical nuclear physicists at Jefferson Lab has revealed that a quark's spin may be altered by the surroundings of the proton or neutron in which it resides. This surprising result, recently published in the journal, Physical Review Letters, may lead to new insights about how ordinary matter is constructed.

The Accelerator Division's Institute for Superconducting Radiofrequency (SRF) Science & Technology is a world leader in SRF accelerator technology research and design. Now the newest idea out of the Institute may revolutionize the way accelerating cavities are produced -- making the manufacturing process faster and cheaper, while producing cavities that could potentially outperform any other niobium cavities ever tested.

Jefferson Lab's core mission is to study the heart of ordinary matter: the nucleus of the atom. Now Hall A has a new magnet and detector system designed to help physicists look at the nucleus in a whole new light. "BigBite" has debuted in its first experiment at Jefferson Lab.