PHELIX – Status and First Experiments

The high-energy high-power laser system PHELIX (Petawatt High Energy Laser for heavy Ion eXperiments) [1] is currently under construction at the Gesellschaft fuer Schwerionenforschung mbH (GSI) Darmstadt. With PHELIX GSI will offer the unique combination of a high-current, high-energy (GeV/u) heavy-ion beam with an intense laser beam. This will open the door to a variety of fundamental science issues in the field of atomic physics, plasma physics and nuclear physics. The project will gain further interest in the near future by the dramatic increase of the accelerator performance with the starting FAIR project at GSI [2]. This paper reports the current status of the project as well as the laser architecture. The proposed physics program and a first experiment carried out with PHELIX, the realization of a transient collisionally excited x-ray laser [3], will also be reviewed briefly.     

Optimization toward a high-average-brightness soft-x-ray laser pumped at grazing incidence

We report the near-field imaging characterization of a 10 Hz Ni-like 18.9 nm molybdenum soft-x-ray laser pumped in a grazing incidence pumping (GRIP) geometry with a table-top laser driver. We investigate the effect of varying the GRIP angle on the spatial behavior of the soft-x-ray laser source. After multiparameter optimization, we were able to find conditions to generate routinely a high-repetition-rate soft-x-ray laser with an energy level of up to 3 microJ/pulse and to 6x10(17) photons/s/mm2/mrad2/(0.1% bandwidth) average brightness and 1x10(28) photons/s/mm2/mrad2/(0.1% bandwidth) peak brightness.     

Transient collisionally excited X-ray laser in nickel-like zirconium pumped with the PHELIX laser facility

A transient collisionally excited X-ray laser has been put into operation using the front end of the PHELIX laser system as a pump laser. Strong lasing at 22 nm has been observed in nickel-like zirconium. PACS 42.60.-v; 42.55.Vc; 42.62.Fi     

A near subtraction result in metric spaces (the locally closed graph case)

This paper concerns a near subtraction result for multifunctions with locally closed graph in metric spaces.     

Evolutors and Invariance

This paper concerns invariance of multifunctions under evolutors and its characterization through tangency of evolutors to multifunctions. The theory is illustrated by its applications to identity evolutors and to evolutors generated by semilinear perturbed equations.     

Thermally conductive elliptic inhomogeneities in 2D anisotropic solids

The problem of a thermally conductive elliptic hole embedded in an anisotropic thermoelastic solid under a remote uniform heat flow is considered. For the plane problem, solutions are derived by the use of an extended thermoelastic version of the Stroh formalism. The hoop stress around the elliptic hole is obtained in an explicit real form. We analyze the influence of the interior thermal conductivity and the cavity thickness on the temperature and stress on the boundary points of the hole. By comparison with the thermally insulated cavity, we show that the consideration of the interior conductivity may lead to significantly different thermomechanical behaviors. Ana Ursescu on leave from Institute of Mathematical Statistics and Applied Mathematics, Calea 13 Septembrie no. 13, Bucharest, Romania.     

Gamma irradiation of protein-based textiles for historical collections decontamination

In order to investigate the effect of gamma rays on cultural heritage materials, samples of silk and wool fabrics were subjected to accelerated ageing testing and then irradiated with different gamma-ray doses: 10 and 25 kGy. In the data analysis, combining thermal analysis (TG and DTG), infrared spectroscopy (FTIR-ATR) and mechanical tests allowed us to explore the changes in physical and chemical features for silk and wool, in relationship to the radiation doses. This analytical protocol offers a way to examine the behaviour of the textiles made of wool and silk within museum collections and their response to gamma-rays irradiation treatment. An exposure to a dose of 10 kGy did not cause significant changes in the tested properties; however, higher doses initiated irreversible loss in the physical and chemical stability of protein-based fabrics. Increasing the irradiation dose above 10 kGy has drastic effects in the loss of elasticity and the mechanical resistance of the tested yarns.     

Correlation effects on the charge radii of exotic nuclei

The structures and distributions of light nuclei are investigated within a microscopic correlation model. Two particle correlations are responsible for the scattering of model particles either to low momentum- or to high momentum-states. The low momentum states form the model space while the high momentum states are used to calculate the G-matrix. The three and higher order particle correlations do not play a role in the latter calculation especially if the correlations induced by the scattering operator are of sufficient short range. They modify however, via the long tail of the nuclear potential, the Slater determinant of the (A) particles by generating excited Slater’s determinants.      

Evolutors and Invariance

This paper concerns invariance of multifunctions under evolutors and its characterization through tangency of evolutors to multifunctions. The theory is illustrated by its applications to identity evolutors and to evolutors generated by semilinear perturbed equations.