N is the index of refraction of the medium in which the lens is working, that is, between the front lens of the objective and the cover glass of the specimen. The larger the numerical aperture the better the resolving power of the objective. It is used to enable two objectives to be compared and to calculate their resolution. It shows its ability to gather light and resolve fine details of the object. The numerical aperture is a measure of the solid angle covered by an objective. It indicates how the lens can resolve the smallest features of a specimen. Inscribed on every objective lens and on many condenser lenses, is a number called the numerical aperture. “Oil” designates oil immersion objectives 7. Tube length in mm or ∞ for infinity-corrected objectives 4. Structures that lie closer to each other than this distance cannot be resolved in the lateral plane using a conventional optical microscope. This wavelength limits the resolution of the light microscope working in white light to about 200–250 nm. White light wavelength is in the region of 400 to 700 nanometers (nm) with an average wavelength of 550 nm. In the microscope that works using transmitted light, the lateral resolution is determined by only three parameters: the wavelength λ of the illuminating light and the numerical aperture of the condenser NA cond, and the objective NA obj. It is defined as the smallest distance in the plane of the specimen (called the X-Y plane) at which two points of the specimen can still be seen separately and not as one point. The resolving power of a microscope in the specimen plane is called lateral (or XY) resolution. This converter is designed only for transmission (bright-field) microscopy. Plasmas 15, 092703 (2008).Opening angles of the objective and the condenser 1 - objective, 2 - specimen, 3 - condenser, 4 - illuminator α obj is the half the opening angle of the objective and α cond is half the opening angle of the condenser Hall, et al., in Medical Imaging 2002: Physics of Medical Imaging (SPIE, San Diego, 2002), pp. Uyama (Springer-Verlag, Tokyo, 1998), pp. Sayers, Medical Applications of Synchrotron Radiation, Ed. Pikuz, Doctoral Dissertation (FIAN, Moscow, 2007). Filippova, in Advances in Science and Technology, Series Plasma Physics (Moscow, 1981), Vol. Blokhina (Inostrannaya Literatura, Moscow, 1960). The method of the determination of the size of a radiation source from calculations of Fresnel-Kirchhoff integrals makes it possible to determine the size with an accuracy that exceeds the diffraction limit, which frequently restricts the resolution of standard methods. Our calculations show that the size of the source is in the range 0.7–2.8 μm. For four different high-current generators, we have calculated the sizes of sources of soft X-ray radiation from X-ray patterns of corresponding objects using Fresnel-Kirchhoff integrals. The size of the radiation source in different setups and configurations can be different. In this work, as a point source of soft X-ray radiation for radiography with a high spatial and temporal resolution, radiation from a hot spot of X-pinches is used. For projection radiography, the small size of the source is the most important characteristic of the source, which mainly determines the spatial resolution of the method. The main method that ensures a high spatial resolution is the method of point projection X-ray radiography, i.e., radiography from a point and bright radiation source. In traditional X-ray radiography, which has been used for various purposes since the discovery of X-ray radiation, the shadow image of an object under study is constructed based on the difference in the absorption of the X-ray radiation by different parts of the object.
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