Measurement of γp→K + Λ and γp→K + Σ 0 at photon energies up to 1.47 GeV

The reactions pK ⁺ and pK ^{+ 0} have been measured with the multiparticle detector system SAPHIR at ELSA in Bonn. Besides the differential cross sections the polarization and, for the first time, the ⁰ polarization have been determined in a photon induced reaction. All data are presented as functions of the photon energy (from threshold up to 1.47 GeV) and of the kaon production angle (0°–180°). The polarization of both and ⁰ is substantial at all energies and varies strongly with the production angle.This work is supported by the Bundesminister für Forschung und Technologie (BMFT), FK 06 BN 621 I     

Simultaneous SIMS/AES Measurements for the Characterization of Multilayer Systems

The interface region of silicon dioxide layers deposited on indium phosphide was investigated by simultaneous secondary ion mass spectroscopy (SIMS) and Auger electron spectroscopy (AES) depth profile measurements. The results of such measurements depend strongly on the ion species used for sputtering. With Ar⁺ primary ions an enhancement of the P- and In-SIMS signals occurs in the mixing zone at the interface. This effect can be explained by an increase of the ionization yield of In and P in the presence of oxygen from the SiO₂. The use of O₂ ⁺ as sputter ions enlarges the phosphorus peak at the interface while the enhancement of the In-signal diminishes. The simultaneously measured AES spectra give clear evidence of oxygen bonded In and P at the interface. Additionally, preferential sputtering of phosphorus occurs. The understanding of these effects which complicate the interpretation of SIMS and AES depth profile measurements of the system SiO₂/InP allows us to investigate the silicon dioxide layers and the interface region in order to optimize the SiO₂ deposition process, e.g. for surface passivation or MIS structures.