The purpose of this collaboration between the University of Florida (UF; David Gilland, PI), the University of South Florida (USF; Claudia Berman, Maria Kallergi, PIs) and Thomas Jefferson National Accelerator Facility (Jefferson Lab) is to design, build and evaluate compact, mobile, high resolution gamma ray and positron medical imaging devices. The targeted applications are molecular imaging of heart disease and breast cancer. Mobile gantries with articulated arms will position the imaging cameras close to the body.
The Jefferson Lab Detector and Imaging Group in collaboration with Oak Ridge National Laboratory (Dr. Justin Baba), Johns Hopkins University (Dr. Martin Pomper) and the University of Sydney (Dr. Steve Meikle) is developing an imaging methodology that utilizes SPECT and X-ray CT for small animal research. The primary challenging task of this project is to develop a SPECT imaging system to allow molecular imaging of unrestrained and un-anesthetized mice.
The high-Q superconducting cavities being developed at JLab have complicated RF control, with large Lorentz detuning at start up. Typically, Lorentz detuning can be much larger than the loaded cavity bandwidth. Several near-term (e.g. JLab 12 GeV project) and longer-term (e.g. ERLs) projects will involve operation of a large number of high-Q superconducting cavities. Of particular importance in these machines is the stability with respect to ponderomotive instabilities, rapid turn-on time and recovery from a trip.
A positron emission mammography/tomography (PEM/PET) biopsy device is being developed to detect suspicious breast lesions and then to guide needle biopsies of these lesions in women who have indeterminate mammograms because of dense or fibroglandular breasts. The PI of this NIH-funded project is Ray Raylman at West Virginia University (WVU). Jefferson Lab will design and build two sets of large-area PEM detectors that will be integrated into a rotating gantry at WVU.
Well-behaved magnetic thin films of stoichiometric alloys, such as an alloy of nickel and iron (NiFe), are not easily formed. Anne Reilly and colleagues at Jefferson Lab and The College of William & Mary excited bulk NiFe with the Jefferson Lab FEL and found a strikingly different response than that found with a conventional titanium-sapphire laser.
Nuclear-spin polarized targets play a key role in experimental nuclear and particle physics. They are essential for understanding how the proton and neutron get their spins from their constituent quarks and gluons and for measuring the electromagnetic structure of these nucleons in both their ground and excited states. While the Jefferson Lab Frozen Spin Target (FROST) is the fourth and latest polarized target to be used at JLab, it is the first to be entirely designed and built here.
The ratios μpGEp/GMp from two JLab recoil polarization experiments, compared to the Rosenbluth separation data (left) and with several theoretical calculations (right).
Jefferson Lab has four experimental halls. The smallest of these is Hall B, measuring roughly 98 ft in diameter and 65 ft from floor to ceiling. From 1995 to 2012, the heart of the Hall B physics program involved the use of a particle detector system known as “CLAS,” an acronym that stands for the CEBAF Large Acceptance Spectrometer. This magnetic spectrometer was based on a superconducting toroid and measured the trajectories of charged particles created in interactions of the beam with a fixed target to determine their momenta.
An effect of color confinement in quantum chromodynamics (QCD) is that traditional perturbation theory breaks down at large distances and low energies. A quantitative understanding of the strong interaction in this region remains one of the greatest intellectual challenges in physics. The symmetries of QCD in the chiral limit (in which the quark mass vanishes) are an important element in resolving this problem.
One of the principal challenges of QCD is to bridge the small- and large-scale behavior of the strong nuclear interactions. At short distances, perturbative QCD is very successful in describing nucleon structure in terms of quarks and gluons. At large distances, the effects of confinement impose a more efficient description in terms of collective hadron degrees of freedom. Despite this apparent dichotomy, an intriguing connection has been observed between the low- and high-energy data on nucleon structure functions, which is referred to as "quark-hadron duality."
