Nuclear Sizes and the Isotope Shift

Darwin-Foldy nuclear-size corrections in electronic atoms and nuclear radii are discussed from the nuclear-physics perspective. Interpretation of precise isotope-shift measurements is formalism dependent, and care must be exercised in interpreting these results and those obtained from relativistic electron scattering from nuclei. We strongly advocate that the entire nuclear-charge operator be used in calculating nuclear-size corrections in atoms, rather than relegating portions of it to the non-radiative recoil corrections. A preliminary examination of the intrinsic deuteron radius obtained from isotope-shift measurements suggests the presence of small meson-exchange currents (exotic binding contributions of relativistic order) in the nuclear charge operator, which contribute approximately 1/2%.Comment: 17 pages, latex, 1 figure -- Submitted to Phys. Rev. A -- epsfig.sty require

Measurement of the 3He(e,e'p)pn reaction at high missing energies and momenta

Results of the Jefferson Lab Hall A quasielastic 3He(e,e'p)pn measurements are presented. These measurements were performed at fixed transferred momentum and energy, q = 1502 MeV/c and omega = 840 MeV, respectively, for missing momenta p_m up to 1 GeV/c and missing energies in the continuum region, up to pion threshold; this kinematic coverage is much more extensive than that of any previous experiment. The cross section data are presented along with the effective momentum density distribution and compared to theoretical models.Comment: 5 pages, 3 figures, updated to reflect published paper: minor text changes from previous version along with updated and added reference

The Quasielastic 3He(e,e'p)d Reaction at Q^2 = 1.5 GeV^2 for Recoil Momenta up to 1 GeV/c

We have studied the quasielastic 3He(e,e'p)d reaction in perpendicular coplanar kinematics, with the energy and momentum transferred by the electron fixed at 840 MeV and 1502 MeV/c, respectively. The 3He(e,e'p)d cross section was measured for missing momenta up to 1000 MeV/c, while the A_TL asymmetry was extracted for missing momenta up to 660 MeV/c. For missing momenta up to 150 MeV/c, the measured cross section is described well by calculations that use a variational ground-state wave function of the 3He nucleus derived from a potential that includes three-body forces. For missing momenta from 150 to 750 MeV/c, strong final-state interaction effects are observed. Near 1000 MeV/c, the experimental cross section is more than an order of magnitude larger than predicted by available theories. The A_TL asymmetry displays characteristic features of broken factorization, and is described reasonably well by available models.Comment: 5 pages, 3 figures, submitted to Physical Review Letters, v3: changed conten

Moscow-type NN-potentials and three-nucleon bound states

A detailed description of Moscow-type (M-type) potential models for the NN interaction is given. The microscopic foundation of these models, which appear as a consequence of the composite quark structure of nucleons, is discussed. M-type models are shown to arise naturally in a coupled channel approach when compound or bag-like six-quark states, strongly coupled to the NN channel, are eliminated from the complete multiquark wave function. The role of the deep-lying bound states that appear in these models is elucidated. By introducing additional conditions of orthogonality to these compound six-quark states, a continuous series of almost on-shell equivalent nonlocal interaction models, characterized by a strong reduction or full absence of a local repulsive core (M-type models), is generated. The predictions of these interaction models for 3N systems are analyzed in detail. It is shown that M-type models give, under certain conditions, a stronger binding of the 3N system than the original phase-equivalent model with nodeless wave functions. An analysis of the 3N system with the new versions of the Moscow NN potential describing also the higher even partial waves is presented. Large deviations from conventional NN force models are found for the momentum distribution in the high momentum region. In particular, the Coulomb displacement energy for nuclei ^3He - ^3H displays a promising agreement with experiment when the ^3H binding energy is extrapolated to the experimental value.Comment: 23 pages Latex, 9 figures, to appear in Phys.Rev.

Precision Measurement of the Spin-dependent Asymmetry in the Threshold Region of 3He⃗(e⃗,e′)^3\vec{\mathrm{He}}(\vec{e},e')

We present the first precision measurement of the spin-dependent asymmetry in the threshold region of $^3\vec{\rm He}(\vec{e},e')$ at $Q^2$-values of 0.1 and 0.2 (GeV/c)$^2$. The agreement between the data and non-relativistic Faddeev calculations which include both final-state interactions (FSI) and meson-exchange currents (MEC) effects is very good at $Q^2$ = 0.1 (GeV/c)$^2$, while a small discrepancy at $Q^2$ = 0.2 (GeV/c)$^2$ is observed.Comment: 5 pages, 2 figures, 2 tables. To appear in Phys. Rev. Let

The Transverse Asymmetry AT′\bf A_{\bf T'} from Quasi-elastic 3He⃗(e⃗,e′)^3\vec{\rm He}(\vec{e},e') Process and the Neutron Magnetic Form Factor

We have measured the transverse asymmetry from inclusive scattering of longitudinally polarized electrons from polarized 3He nuclei at quasi-elastic kinematics in Hall A at Jefferson Lab with high statistical and systematic precision. The neutron magnetic form factor was extracted based on Faddeev calculations with an experimental uncertainty of less than 2 %.Comment: 4 pages, 2 figures, revtex, accepted for publication in PR

Influence of Doping Concentration on the Properties of Tin Doped Zinc Oxide Thin Films Prepared by Spray Pyrolysis for Photovoltaic Applications

This work reports on the preparation and characterization of zinc oxide (ZnO) thin films by spray pyrolysis on glass substrates. The effect of Sn doping with 1% Sn (TZO-1.00), 1.5% Sn (TZO-1.50), 2% Sn (TZO-2.00) on the structural, optical and electrical properties of the obtained films was studied. The obtained films are characterized by different techniques such as X-ray diffraction (XRD), UV-visible and electrical Hall Effect measurements. The results of the XRD characterization indicate that all the films have the polycrystalline hexagonal wurtzite structure with a preferred orientation (002). Spectroscopic measurements in the UV-VIS-IR wavelength range were found to give good average transmittance values of about 70%, with a high transmittance of 75% with 1.5% Sn doping. The optical gap value increases in the range of 3.23 to 3.29 eV with increasing tin content. The electrical analysis shows that the conductivity improves slightly with doping compared to the pure ZnO film

Tco’s Thin Films Grown By Spray Pyrolysis Technique For Window Layer Of Solar Cell Application: A Comparative Study

Thin films of ZnO, SnO2 and CdO have been deposited using spray pyrolysis technique. They were characterized by X-Ray diffraction (XRD), optical absorption in the wavelength range 200-2500 nm and Hall Effect measurements. A comparative study was conducted for the prepared TCO’s thin films. The structural studies revealed the formation of polycrystalline thin films with a hexagonal wurtzite and tetragonal rutile structure for ZnO and SnO2 thin films respectively, whereas a cubic structure was found for the CdO films. Optical studies showed that the prepared SnO2, ZnO and CdO thin films had a direct band gap of 3.72, 2.98 and 2.43 eV, respectively. The ZnO films exhibited highest optical transmittance that varied between 70% - 88%. The film thickness of the samples was estimated from transmission spectra. The effective mass of the carriers (m*) at the Fermi level and the figure of merit of the deposited films are also investigated. Hall Effect measurements confirm the n-type nature of the TCO’s thin films. A low resistivity in the order of 10-2 (Ω.cm) has been observed for SnO2 and CdO thin films