Reflective Optical Structures and Imaging Detector Systems

Abstract

New types of grazing incidence X-ray mirror systems based on single reflections have been studied, including modelling of optical performance, effects of surface figure errors and micro-roughness, actual performances and astronomical and laboratory applications. Ray-tracing simulations of multi-foil reflective optics for focusing radiation from a gas puff plasma source have been studied in detail for soft X-rays in the wavelength range 3–20 nm. Such sources are debris free because of the use of noble gases as the working medium. The ray-tracing was performed for both point and extended sources. The optics consist of two orthogonal stacks of ellipsoidal mirrors with gold reflecting surfaces forming a double focusing device. Unlike multilayer optics, grazing incidence optics are efficient at focusing soft X-rays over a wide wavelength range. Optics designed for collecting solid angle of 0.1sr were manufactured and tested in the visible and EUV regions. It has been demonstrated that multi-foil optics are a good candidate for concentrators of EUV radiation in applications such as lithography. High resolution imaging screens and detector systems with thin YAG:Ce and other monocrystal scintillator screens have been designed and tested. Camera systems based on monocrystal scintillator, optics and CCD detector were built and used for testing of scintillators. Screens with thicknesses down to 5 ?m and a fast, high resolution, cooled 16 bit CCD camera have been used to achieve resolutions of 1 ?m and comparative studies of sensitivity (for YAG:Ce and fine grain Gadox screen) were carried out. Scintillator screens and systems with sub-micrometre resolution have also been studied.