Absolute differential cross sections for the elastic scattering of alpha particles by N 15 have been measured in a differentially-pumped gas scattering chamber. The measurements were made at center-of-mass angles of 169.1, 149.5, 140.8, 125.3, 90.0, and 70.0 degrees for alpha-particle energies from 1.75 to 5.50 Mev, corresponding to 5.37-to 8.33-Mev excitation of the compound nucleus F 19 . The experimental widths of the levels observed below approximately 3.5-Mev bombarding energy are generally narrow, in most cases less than 10 kev. Above 3.5 Mev a marked increase in the level width was observed. As a result of an analysis based on the Wigner-Eisenbud reaction theory, values of /, ir, E\, and Y\ 2 were assigned to 16 levels in F 19 .

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Measuring solid-state quantum yields: The conversion of a frequency-doubled Nd:YAG diode laser pointer module into a viable light source Rev.

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Infrared (IR) spectroscopy, nuclear reaction analysis (NRA), and Rutherford backscattering (RBS) were used on semi-insulating polycrystalline silicon (SIPOS) films deposited at atmospheric pressure (AP) and low pressure (LP) to determine film composition and hydrogen content. The amount of hydrogen in SIPOS ranges from less than 0.1 at. % H for films annealed in nitrogen at 800 °C for 30 min to 11 at. % H for higher oxygen content LP SIPOS films. For AP SIPOS films, the H content is directly proportional to the O content of the film and is uniformly distributed with depth into the SIPOS film. Based on the absorption cross section, the narrow, very weak 2270-cm−1 peak in the IR is identified as the Si-H absorption. The higher oxygen content LP SIPOS film contains additional H not bound as Si-H. The IR, NRA, and RBS data are interpreted in terms of a structural model involving Si-H and Si-O where the O is nonbridging. The 865-cm−1 peak in the IR is believed due to this nonbridging O-Si interaction.