We have developed a LURE a code to predict the efficiency of gratings. The code is based on differential theory and uses a simplified R-matrix propagation algorithm to obtain numerical stability on the whole range from visible to hard x-rays. Experimental and numerical studies have been performed on some test cases at a synchrotron source. A good agreement between numerical prediction and measurements has been found. The code is a rigorous application of electromagnetic theory and gives exact results as long as accurate optical constants can be attributed to grating materials. Such rigorous calculations provide an important tool for the optical engineering of modern synchrotron monochromator gratings. We give an example of application of this code to the engineering of a modern beam line and for the optimization of harmonic rejection.

A new instrumentation program was decided in 1996 to renew LURE's aging beamline equipment, and also get some experience in view of a new French synchrotron source. For the VUV and soft X-ray domain which are covered by the low energy machine Super-ACO, three new beamlines were scheduled over a three year period with a clear goal toward resolution. Two soft X-ray beamlines are equipped with grazing incidence monochromators, a spherical grating monochromator (SGM) and a plane grating monochromator; a VUV beamline will use an off-plane Eagle normal incidence monochromator. The particular features of each beamline are described. Some emphasis is given to the design, construction and alignment principles which have been followed to the insure an optical quality. A status of the program advance is given. Results from the already commissioned SGM beamline are reported.

The techniques of monochromator optimization are reviewed, and it is shown that until recently only a few of the available parameters were used at the same time. Efficient optimization can be performed numerically. The computation method developed at LURE is explained and an example is given. Extension and development of the method are outlined.

The development of third-generation synchrotron sources has stimulated efforts toward high-resolution monochromators. A good knowledge of grating efficiency is needed to achieve an optimal compromise between resolution and photon flux. Because simple geometric models fail to describe correctly the gratings properties in the UVtosoft-X-ray range, we have developed a simulation software based on differential theory. A simplified R-matrix propagation algorithm assures the numerical stability of the code for deep gratings. Our numerical results are compared with previous research on deep gratings. Experimental and numerical studies have been performed on some test cases at a synchrotron source. Very good agreement between numerical prediction and measurement has been found.

The achievement of high resolving power from VUV to soft X-rays is a new challenge for synchrotron radiation beam-lines. When the X-UV range has to be privileged, we show that an optimized Plane grating monochromator (PGM), which can be corrected up to large aperture angles, offer a good compromise between resolution, flux and easiness of use. The design method and especially the determination of deviation angles and gratings parameters are outlined. The dependence of ultimate performances on the fabrication accuracy is evaluated; This design is compared to an alternative SGM design and their performances are found complementary.

Though optimization softwares are commonly used in visible optical design, none seems to exist for soft x-ray optics. It is shown here that optimization techniques can be applied with some advantages to X-UV monochromator design. A merit function, suitable for minimizing the aberrations is proposed, and the general method of computation is described. Samples of the software inputs and outputs are presented, and compared to reference data. As an example of application to soft X-ray monochromator design, the optimization of the soft X-ray monochromator of the ESRF microscopy beamline is presented. Good agreement between the predicted resolution of a modified PGM monochromator and experimental measurements is reported.