Laboratory based GIXRF and GEXRF spectrometers for multilayer structure investigations

This work reports laboratory angle resolved XRF measurements with the goal of establishing laboratory techniques to obtain a more complete idea of the intralayer composition of multilayer samples.

Finite Element Modeling of Parabolic Trough Mirror Shape in Different Mirror Angles

Deviations from the ideal shape of reflector panels for parabolic trough solar power plants can have relevant impact on field efficiency and thus on the performance of the whole power plant. Analyzing the gravity-induced deformation of mirror shape for different mirror angles is relevant for performance calculation of solar parabolic trough collectors and identifying optimization potential of the mirror panels. Two mirror model cases (stiff and elastic supports) are evaluated in four angles: in horizontal laboratory angle (mirrors facing upward with mounting points horizontally aligned), and in 0 deg, 45 deg, and 90 deg collector angle. The resulting slope maps are calculated in a separate postprocessing. In order to evaluate the effect of gravity load on mirror shape, the deformed mirror in each evaluated angle is compared to the nondeformed mirror shape, and to the shapes in 0 deg (zenith) collector angle, respectively. The resulting slope deviation maps show the mirror deformation in different mirror angles. Stiffness of the mounting to the support structure has a relevant impact. Mirror deformation on elastic brackets (SDx up to 1.6 mrad) is much more pronounced than on an ideal stiff support structure (SDx up to 1.0 mrad).

Finite Element Modeling of Parabolic Trough Mirror Shape in Different Mirror Angles

Deviations from the ideal shape of reflector panels for parabolic trough solar power plants have relevant impact on field efficiency and thus on the performance of the whole power plant. Analyzing the gravity-induced deformation of mirror shape for different mirror angles is relevant for performance calculation of solar parabolic trough collectors and identifying optimization potential of the mirror panels. Two mirror model versions (stiff and elastic supports) are evaluated in four angles: in horizontal laboratory angle (mirrors facing upward with mounting points horizontally aligned), and in 0°, 45° and 90° collector angle. The resulting slope maps are calculated in a separate post-processing. In order to evaluate the effect of gravity load on mirror shape, the deformed mirror in each evaluated angle is compared to the non-deformed mirror shape, and to the shapes in 0° (zenith) collector angle, respectively. The resulting slope deviation maps show the mirror deformation in different mirror angles. Stiffness of the mounting to the support structure has a relevant impact. Mirror deformation on elastic brackets (SDx up to 1.6 mrad) is much more pronounced than on an ideal stiff support structure (SDx up to 1.0 mrad).

Energy spectra of Ag, Au, Sn, and Pb ions emitted from laser-created plasmas determined from their implantation depth profile in a metallic substrate

The energy spectra of heavy ions emitted from laser-produced plasmas were determined by the use of a technique relying on the implantation of plasma ions into a substrate located close to the plasma. Ion energy spectra were reconstructed from depth profiles of the implanted ions measured by the standard Rutherford back-scattering (RBS) technique employing 2 MeV alpha particles scattered at 170° laboratory angle. The energy spectra of Ag, Au, Sn, and Pb ions, implanted into aluminum or steel foils, are presented. A review of other techniques for ion energy spectrum measurement is presented and their limitations are discussed.

Coulomb Excitation of 142Ce and 144Nd

The N = 84 nuclei 142Ce and 144Nd have been Coulomb-excited using 4He, 12C and 160 projectiles. Scattered particles were detected at a mean laboratory angle of 170.6� with an annular silicon surface-barrier detector. The static quadrupole moment f the 2t state was determined for both nuclei. In addition, various electromagnetic transition probabilities involving the 2~, 2~, 1 and 4t states were measured. Taken in conjunction with previous information, the results show that the properties of 142Ce nd 144Nd are well described by the vibrational U(S) limit of IBM-2, and strongly support the proposition that the 2~ level in each nucleus is an essentially pure one d-boson mixed-symmetry state.

The 1·67 MeV Level in 9Be

A study has been made of the 1� 67 MeV level in 9Be using 6� 0 MeV protons to populate it via the 9Be(p, p')9Be* reaotion. The speotrum of protons inelastioally soattered at a 90� laboratory angle was fitted with a line shape based on R�matrix theory. The position of the line� shape peak above the sBe + n threshold is 25 � H ke V; this value and deduoed level parameters are in disagreement with recent results from a similar fit to the 9Be(1', n)SBe reaotion.

Study of Bound Nucleon Wave Functions by Coulomb Stripping in the Reaction 208Pb(d, p)209Pb

The differential cross sections of the 208Pb(d, p)209Pb transitions to the states 9/2+, 5/2+*, ½+, 7/2+, and 3/2+ in 209Pb were measured at 135° laboratory angle for deuteron energies between 7.0 and 10.5 MeV. The data below 8.0 MeV were analyzed in COULOMB Wave BORN Approximation to give accurate spectroscopic factors of the five levels according to a simple shell model potential in the final nucleus. The dependence on some of the parameters that determine this potential is studied. The absolute value of the normalizing constants of the bound neutron wave functions outside the nuclear potential well are determined without reference to any shell model potential, i. e. their true values are given. It is confirmed that the ground and excited states up to 2.52 MeV in 209Pb are pure single particle states so that from their study one can draw a proper shell model potential in the lead region.