Hydrogen interaction with EUVL-relevant optical materials

Mo/Si multilayer mirrors were exposed to deuterium ions with well-defined energies in order to gain insight into the effects of Extreme UV light driven plasma generation on reflective elements in commercial lithography equipment. Post-irradiation analysis by Rutherford Backscattering Spectrometry showed erosion of both Mo and Si layers for the highest energy 50 eV/D and exposure time 5.4 × 10⁴ s. Nuclear Reaction Analysis revealed detectable deuterium retention for energies ⩾25 eV/D. Surface analysis by X-ray Photoelectron Spectroscopy showed erosion of the first Si layer for energies ⩾5 eV/D. Inferences on the spatial distribution of trapped deuterium are made on the basis of available data regarding deuterium retention in the materials in question.     

Electromagnetic low-energy constants in χPT

We investigate three-flavour chiral perturbation theory including virtual photons in the limit in which the strange quark mass is much larger than the external momenta and the up and down quark masses, and where the external fields are those of two-flavour chiral perturbation theory. In particular, we work out the strange quark mass dependence of the electromagnetic two-flavour low-energy constants C and k_i. We expect that these relations will be useful for a more precise determination of the electromagnetic low-energy constants. PACS 11.30.Rd; 12.39.Fe; 13.40.Dk; 13.40.Ks     

Multiwavelength Q-switched CO2 laser with continuous discharge

A low-pressure (20 mbar) CO₂ laser allows to extract pulses at several selected wavelengths simultaneously from the same active medium. We demonstrated this, using an industrial laser modified by a Q-switch and a resonator with two branches. In one branch the wavelengths are spatially separated, whereas in the other they oscillate in one common transverse mode. We designed a multi-wavelength resonator which requires a single additional reflector compared to usual laser cavities. It provided tunable oscillation at six wavelength simultaneously.     

Effective interactions in the Λ-α and Λ-Λ-α systems

The neutron-rich nuclei³³Si,³⁴Si,³⁵Si,³⁵P,³⁶P,³⁷S and³⁸S were investigated by studying¹⁴C and¹⁸O — induced transfer reactions on³⁶S using aQ3D magnetic spectrograph and a position sensitive focal plane gas detector. The previously unknown mass of the isotope³⁵Si was determined. The accuracy of the mass excess values of the isotopes³³Si,³⁴Si,³⁵P and³⁶P has been improved. Excited states of the isotopes³³Si,³⁴Si,³⁵P,³⁶P and³⁸S were identified for the first time. In addition theγ-decay of excited states in³⁷S and³⁸S was studied with a Ge(Li) detector in coincidence with theQ3D focal plane detector. Experimental values for the mass excesses are compared with published mass formulae.     

High spin states and pairing vibrations

The Generator-Coordinate-Method is applied to describe yrast-bands and excited vibrational bands of pairing-vibrational orβ-vibrational type in deformed rare earth nuclei. The model wave functions are supplied by the Pairing+Quadrupole-Model with angular momentum — and particle number projection. Results are shown for the nucleus¹⁷⁰Yb. The question if backbending may be produced by the intersection of the ground and the neutron pairing vibrational band is discussed.