[en] Examples are given of dynamically polarized targets in use today and how the subsystems have changed to meet the needs of todays experiments. Particular emphasis is placed on target materials such as ammonia and lithium deuteride. Recent polarization studies of irradiated materials such as butanol, deuterated butanol, polyethylene, and deuterated polyethylene are presented. The operation of two non-DNP target systems as well as applications of traditional DNP targets are briefly discussed

[en] We report on the progress of the Dynamically Polarized Sample at the Spallation Neutron Source. The SNS DPS is a collaborative project with the University of Virginia constructed for the purpose of polarized neutron scattering and diffraction. The project aims at significantly enhancing the signal-to-noise ratio by utilizing the strong spin dependent scattering cross section of hydrogen. One of the areas that are expected to benefit from this project is neutron protein crystallography, where a 10 fold gain in diffraction intensity and 10 fold reduction in incoherent background are within reach. The first step of the SNS DPS project uses a simple one Kelvin refrigerator and a 5 Tesla magnet. Our final goal is to design and build optimized setups for instruments such as the neutron protein diffractometer at the SNS (MaNDi). A brief overview of the DPS project will be given.

[en] The Hinkler Well - Centipede deposits are near the northeastern margin of the Archean Yilgarn Block on a drainage system entering Lake Way. Basement rocks are granitoids and greenstones. The rocks are deeply weathered and overlain by alluvism. Granitoids, the probable uranium source, currently contain up to 25 ppm uranium, in spite of the weathering. The host calcrete body is 33 km long and 2 km wide. Uranium up to 1000 ppm occurs in carnotite over a 15 km by 2.5 km area. (author)

[en] Polarized electron beams have been successfully used at Jefferson Lab for over a year. We now report the successful achievement of polarized targets for nuclear and particle physics experiments using the dynamic nuclear polarization (DNP) technique. The technique involves initial irradiation of frozen ammonia crystals (NH₃ and ND₃), using the electron beam from the new Free Electron Laser (FEL) facility at Jefferson Lab, and transferring the crystals to a special target holder for use in Experimental Halls. By subjecting the still ionized and frozen ammonia crystals to a strong magnetic field and suitably tuned RF, the high electron polarization is transmitted to the nucleus thus achieving target polarization. Details of the irradiation facility, the target holder, irradiation times, ionized crystal shelf life, and achieved polarization are discussed

[en] We have built a polarimeter in order to measure the electron beam polarization in hall C at JLAB. Using a superconducting solenoid to drive the pure-iron target foil into saturation, and a symmetrical setup to detect the Moeller electrons in coincidence, we achieve an accuracy of <1%. This sets a new standard for Moeller polarimeters

[en] It has been proposed that the Siverse transverse single spin asymmetry in Drell-Yan production in transversely polarized p+p collisions would have an opposite sign compared to what has been observed in the polarized Semi-Inclusive Deep Inelastic Scattering (SIDIS) experiments. Experimental confirmation or disproval of this prediction would provide a novel fundamental test of QCD and shed new light on our theoretical understanding of the transverse spin physics phenomena. We discuss the prospects and physics sensitivities of polarized fixed target Drell-Yan experiments that could utilize the existing proton and other hadron beams at Fermilab, and polarized proton beams at RHIC with a polarized solid proton and/or neutron target option. We show that if realized, the new experiments would provide critical measurements of not only the sign change (or not) of Sivers functions, but also the information of quark and antiquark's Sivers distributions over a wide kinematic range.

[en] Models of baryon structure predict a small quadrupole deformation of the nucleon due to residual tensor forces between quarks or distortions from the pion cloud. Sensitivity to quark versus pion degrees of freedom occurs through the Q² dependence of the magnetic (M₁₊) , electric (E₁₊) , and scalar (S₁₊) multipoles in the γ^*p→Δ⁺→pπ⁰ transition. We report new experimental values for the ratios E₁₊/M₁₊ and S₁₊/M₁₊ over the range Q²=0.4-1.8 GeV² , extracted from precision p(e, e^'p)π⁰ data using a truncated multipole expansion. Results are best described by recent unitary models in which the pion cloud plays a dominant role

[en] Double-polarization asymmetries for inclusive ep scattering were measured at Jefferson Lab using 2.6 and 4.3 GeV longitudinally polarized electrons incident on a longitudinally polarized NH₃ target in the CLAS detector. The polarized structure function g₁(x,Q²) was extracted throughout the nucleon resonance region and into the deep inelastic regime, for Q²=0.15-1.64 GeV². The contributions to the first moment Γ₁(Q²)=∫g₁(x,Q²) dx were determined up to Q²=1.2 GeV². Using a parametrization for g₁ in the unmeasured low x regions, the complete first moment was estimated over this Q² region. A rapid change in Γ₁ is observed for Q²<1 GeV², with a sign change near Q²=0.3 GeV², indicating dominant contributions from the resonance region. At Q²=1.2 GeV² our data are below the perturbative QCD evolved scaling value

[en] We have examined the spin structure of the proton in the region of the nucleon resonances (1.085 GeV< W<1.910 GeV) at an average four momentum transfer of Q²=1.3 GeV². Using the Jefferson Lab polarized electron beam, a spectrometer, and a polarized solid target, we measured the asymmetries A_parallel and A_{perpendicular} to high precision, and extracted the asymmetries A₁ and A₂, and the spin structure functions g₁ and g₂. We found a notably nonzero A_{perpendicular}, significant contributions from higher-twist effects, and only weak support for polarized quark-hadron duality

[en] We present the Bjorken integral extracted from Jefferson Lab experiment EG1b for 0.05< Q²<2.92 GeV². The integral is fit to extract the twist-4 element f₂^p-n which appears to be relatively large and negative. Systematic studies of this higher twist analysis establish its legitimacy at Q² around 1 GeV². We also performed an isospin decomposition of the generalized forward spin polarizability γ₀. Although its isovector part provides a reliable test of the calculation techniques of chiral perturbation theory, our data disagree with the calculations.