Showing papers by "Joachim Schulz published in 2001"

2p photoelectron spectra and linear alignment dichroism of atomic Cr

Abstract: The 2p photoionization of free Cr atoms has been studied. Unpolarized as well as laser-aligned Cr atoms have been ionized with linearly polarized undulator radiation well above the 2 p ionization thresholds. The investigation of the main and satellite 2 p photoelectron lines and of the linear alignment dichroism allowed for a detailed characterization of the Cr 2 p photoionization process. The spectra are compared to the predictions of the pure jK coupling model and to the results of intermediate coupling Hartree-Fock calculations. The importance of the investigations for the discussion of the 2 p photoelectron spectra of bound 3d transitionmetal atoms is pointed out.

Gas permeability of adhesives and their application for hermetic packaging of microcomponents

Abstract: The use of adhesives with low gas permeability in packaging microcomponents provides a simple, low-cost alternative to the standard techniques for hermetic packaging. The permeability to helium of various epoxy resin adhesives was determined by means of a mass spectrometer in reference specimens of defined dimensions. The adhesive with the lowest permeability to helium was chosen to bond an evacuated LIGA gyrometer package (flatpack, volume=1.4 cm3). For comparison, a few packages were closed by laser welding. Subsequently, the pressure rise in the sealed packages due to gas permeation and desorption from the walls was measured by the integrated microsensor, and the permeation rate was determined. The permeation rates of as low as 10−17 m3/s achieved in bonded packages are comparable to those measured in laser welded packages.