Silicon is perhaps one of the most important materials in our technological world, but its performance is always ultimately limited by impurities. Mitigation by impurity elimination is not possible, and theoretical understanding is very limited. Thus, these experiments, in which real-time dynamical evolution of excited impurity dynamics is measured, are of high fundamental as well as technological importance.
Jefferson Lab in collaboration with Case Western Reserve University (Dr. Zhenghong Lee) is developing a system that provides fused planar radiopharmaceutical imaging, planar x-ray imaging and planar bioluminescent/fluorescence imaging in a single apparatus for small animal imaging. Jefferson Lab developed a high resolution gamma camera based on a large position sensitive photomultiplier tube coupled to a pixellated NaI(Tl) scintillator array with individual crystal elements 1.3 mm x 1.3 mm x 6 mm in size and 0.2 mm septa between each element (1.5mm pixel step).
Hall D is the newest of Jefferson Lab’s four experimental halls. It is dedicated to the operation of a large-acceptance detector for experiments with a high-energy, polarized photon beam. The experiments are carried out by an international group of scientists called the GlueX collaboration.
New data from CLAS in Hall B probe the magnetic structure of the neutron at large momentum transfers, or small distances, with high precision. The magnetic form factor of the neutron, GMn, has been extracted from measurements of the ratio of quasi-elastic, electron-neutron to electron-proton scattering in deuterium over a Q2 range of 0.5-4.8 (GeV/c)2. The CLAS detector enabled the use of a combination of experimental techniques that allowed unprecedented precision to be achieved at Q2 ≥ 1 (GeV/c)2.
The simplest bound system of neutrons and protons is the deuteron, consisting of one proton and one neutron. In the language of the theory of the strong interaction, quantum chromodynamics (QCD), it is made of six valence quarks (3 up and 3 down), plus the quark-gluon sea. In the standard proton-neutron picture, the deuteron's shape is largely determined by the exchange of a pion, which leads to strong, noncentral "tensor" interactions.
Color polarizabilities: response of the color electric Ec→ and magnetic Bc→ fields in the nucleon when the nucleon is polarized in the direction given by the spin vector S.→
