[en] Laser facilities for Inertial Confinement Fusion (I.C.F.) experiments require laser and X ray optics able to withstand short pulse conditions. After a brief recall of high power laser system arrangements and of the characteristics of their optics, the authors will present some X ray optical developments

[en] An innovative divertor concept for a thermonuclear fusion reactor is being studied at the Institute for Advanced Materials of the Joint Research Centre of the European Communities. It is made of a single material, an ultrahigh thermal conductivity carbon fiber reinforced graphite (CFC) composite; the coolant is helium gas. When looking at the new divertor concept, it is needed to make several numerical calculations in order to investigate the influence of the various parameters to be optimized. This paper shows a new numerical procedure which has been developed to avoid a complete 3D-calculation

[en] Thermal and structural analysis was carried out to evaluate the thermal distortion of a silicon crystal, which was irradiated by X-ray with high intensity. Liquid nitrogen, gallium and water were considered as coolants in this numerical simulation. These results were applied to the evaluation of a rocking curve. According to the results obtained by using the present model, cooling by liquid nitrogen was the most advantageous in view of the rocking curve when photon energy was under 20keV. This advantage, however, disappeared gradually as the photon energy was increased to more than 20 keV

[en] The purpose of this paper is to present REOSC experience in the field of high energy or high power optics. The author reviews some challenging recent achievements which are: a 1.8 meter mirror assembly for the US NAVY, the 1 meter LATEX high energy beam expander telescope, large high energy optics for the CEA laser fusion laboratory, optics for the E.S.R.F. synchrotron prototype adaptive mirror and other beamlines, the LASCO coronograph off-axis parabola

[en] Adaptive optics systems have proved their efficiency to obtain high resolution images in the field of large astronomical telescopes. The same techniques can be applied to correct X-ray mirror shapes. The paper describes the principle of an adaptive X-ray mirror system (mirror architecture, measurement subassembly, control unit). In a second part, first results obtained during the design study of the ESRF adaptive X-ray mirror are given. The possibility to achieve cylindrical or elliptical mirror surfaces using adaptive optics techniques are suggested

[en] Contact thermal conductance is much lower in a vacuum than normal pressure conditions. When one cools SR beamline optics, such as mirror components, a water cooled copper plate which is attached to the optics is used. In order to increase the effect on cooling, an indium sheet or liquid metal, such as Ga, In-Ga, is inserted between the optics and the plate. The authors experimentally obtained contact thermal conductance in a vacuum, which was essential to computing the thermal distribution of optics. And they simulated their cooling system using a beamline mirror component

[en] The directly water-cooled silicon crystal used on the multipole wiggler beam line BLI6 at the Photon Factory has extended cooling fins below the crystal block. Such extended fins are useful to reduce bowing of the crystal due to thermal distortion induced by synchrotron radiation. Experimental and calculated Si(111) and Si(333) double crystal rocking curves are compared in the present paper. Thermal deformation is calculated using a finite element analysis program ANSYS. Fairly good agreement was obtained between experiment and calculation

[en] At the ESRF, the power absorbed by the first optical element will vary between a hundred watts on undulator beamlines, and several kilowatts on wiggler beamlines. One consequence is a distortion of the optical element, leading to a degradation of the performances of the beamline optics. Cooling certain materials (Si, Ge, InSb) to low temperature (typically around 125 K for Si) was proposed as a possibility to reduce the thermal deformation. In this paper, the authors report on the development of liquid nitrogen cooling of silicon crystal monochromators for ESRF beamlines. First, a prototype of a closed liquid nitrogen loop is presented. Then, hydraulic and thermal measurements are given, showing the influence of the flow rate, the pressure and of the absorbed power

[en] Heat transfer experiments were carried out to investigate the boiling characteristics of LN2 (liquid nitrogen) in a narrow channel made by silicon crystal, which simulated one of the cooling channels of first crystal of DXM (double crystal monochromators). Heat transfer coefficients in nucleate boiling and DNB (departure from nucleate boiling) heat fluxs in the narrow channel were obtained and compared with some existing correlations. These values will be used in the numerical simulation to calculate the thermal distortion of the crystal more accurately. The DXM will be installed in the beamlines of large scale Synchrotron Radiation Sources

[en] Preserving the high source brightness of the third generation of synchrotron radiation facilities will require that thermal and pressure deformations of the monochromator crystals be maintained within a few arcseconds. Recent experiments at the National Synchrotron Light Source (NSLS) have demonstrated the potential of adaptive crystal optics to cope with high power densities. In this technique the crystals deformations are minimized both by an efficient water-jet cooling and by externally applied pressure loads. Thermal deformation can be reduced further with diamond crystals because of their high thermal conductivity and low coefficient of thermal expansion. In this paper the authors describe the results achieved by optimization of adaptive crystal optics for diamond crystals