Abstract: A sample vessel for X-ray microscopes comprising a first silicon base plate having an entrance window covered with a thin film of silicon nitride, and a second silicon base plate which has an exit window covered with a thin film of silicon nitride and matched with the entrance window. The second silicon base plate being connected the first base plate by way of a spacer so as to form a sealed space capable of accommodating samples to be observed. Disposed in the space is a mesh member made of a wire material having an angle of contact with water smaller than 90.degree. at a location adjacent to the thin film of silicon nitride covering the entrance window or a thin film of aluminium is evaporation-coated over the thin film of silicon nitride.

Abstract: An X-ray microscope for observing a transmitted X-ray microscopic image of a specimen by irradiating the specimen with X-rays and exciting radiation rays, in which the exciting radiation rays are made incident upon the specimen at a large photon flux in an efficient manner without loss, so that a contrast of the image can be increased. The invention provides a desired relationship between thickness of specimen, wavelength of X-rays and tone resolving power of image for obtaining a transmitted X-ray microscopic image having an excellent contrast. The invention further proposes optimizations for a photon flux of exciting radiation rays as well as for a timing of irradiation of X-rays and exciting radiation rays. The X-ray microscope can observe particular element contained in particular substance without being affected by the same element contained in other substances which constitute a specimen together with the particular substance by suitably selecting a wavelength of the exciting radiation rays.

Abstract: In a soft X-ray microscope including a soft X-ray source for emitting soft X-rays, a condenser lens for focusing the soft X-rays onto a specimen under inspection, an objective lens for focusing soft X-rays emanating from the specimen, a soft X-ray detector for receiving the soft X-rays focused by the objective lens, and a visually observing optical system for forming a visible image of the specimen by converting an optical property of the specimen other than contrast and color into a contrast in brightness or color. The visually observing optical system may be formed as phase contrast microscope, dark field microscope, polarizing microscope, differential interference microscope, or fluorescent microscope. Then, alignment and focus adjustment can be performed by observing the visible image of the specimen without irradiating the specimen with the soft X-rays even if the specimen has substantially no contrast and color.

Abstract: A vacuum optical system has a vacuum chamber for housing an optical system used in a vacuum. The vacuum chamber is equipped with a member, on which the optical system is at least mounted, supported by such parts that when a pressure in the vacuum chamber changes to deform the vacuum chamber, the amount of displacement transmitted to the optical system is smaller than a predetermined tolerance depending on an accuracy necessary for the optical system. Thus, the vacuum optical system can be obtained which does away with the need for readjustment of optical alignment and is compact.

Abstract: A soft X-ray detector includes a surface electrode layer, a photoelectric conversion layer, and a semiconductor detector having an electrode connected to the photoelectric conversion layer, for detecting an electric charge produced In the photoelectric conversion layer. The photoelectric conversion layer and the surface electrode layer have thicknesses satisfying conditionsdA.gtoreq.0.183.lambda./KAdB.ltoreq.0.183.lambda./KBwhere dA is a thickness of the photoelectric conversion layer, dB is a thickness of the surface electrode layer, KA is an extinction coefficient of radiation of a wavelength .lambda. in a substance constituting the photoelectric conversion layer, and KB is an extinction coefficient of radiation of the wavelength .lambda.in a substance constituting the surface electrode layer. Thus, the soft X-ray detector has a high sensitivity to soft X rays and a lower sensitivity to visible light, so that only soft X rays can be selectively detected.

Abstract: An X-ray microscope has an X-ray filter for transmitting a wavelength between 43.7 and 65 .ANG. and a light source for emitting ultraviolet light of a wavelength of at least 100 nm in an optical path so that a specimen is irradiated with X rays and an image of an object is formed by an X-ray detector, in which the ultraviolet light is reflected from the X-ray filter to irradiate the specimen. Thus, the X-ray microscope allows biological observation to be made with a transmitted microscopic image of high quality and has advantages in design and choice of materials in fabricating its system.

Abstract: An X-ray multilayer film reflecting mirror comprises a plurality of substance layers formed on a substrate to be applied to X-rays having a wavelength of 100 .ANG. or less so that a deviation .DELTA. of the film thickness of each layer from a standard value is within a range defined by ##EQU1## where .theta. is the grazing angle of an X-ray being incident and .lambda. is the wavelength of the X-ray. Thus, the multilayer film reflecting mirror having the reflectance which is advantageous in practical use can be stably provided, and a product yield is improved.

Abstract: In a Schwarzschild optical system comprising a concave mirror having an aperture at its center and a convex mirror disposed in face of the concave mirror, the convex mirror is coated with a multilayer film such that an incident angle .theta.02 on the convex mirror at which reflectance is maximized with respect to light of a particular wavelength satisfies the following condition:By such structure, the Schwarzshild optical system of the present invention provides an important advantage in practical use that transmittance efficiency is extremely favorable..alpha.(.theta.02, N.A.).gtoreq.0.5 .alpha..sub.max.theta.1 .sub.min <.theta.01<.theta.1.sub.

Abstract: An X-ray detector, which is concerned with X-rays having wavelengths of less than 100 .ANG., includes an X-ray filter with a thickness smaller than a previously defined value, a semiconductor light-receiving element arranged behind the X-ray filter, and a measuring device for measuring an output produced by the semiconductor light-receiving element. This detector is provided with a grazing incidence mirror in front of the X-ray filter so that the wavelength selection and intensity measurement can be effected simultaneously. The X-ray detector has important advantages in practical use that the power source system does not come to a large scale, its periphery circuit is simple, and sensitivity is as high as one to two orders than that of a conventional X-ray diode.

Abstract: An optical system for X rays having a multilayer reflecting mirror which has high reflectances for X rays of different wavelengths. One type of multilayer reflecting mirror is such that the mirror surface of the multilayer reflecting mirror is divided into a plurality of regions, and the regions are provided with multilayers which are such that the reflectance of each multilayer is maximum for X rays of a corresponding wavelength. Another type of multilayer reflecting mirror has a substrate and a plurality of multilayer laid on the substrate, wherein the wavelength of X rays to be reflected with a maximum reflectance varies from multilayer to multilayer. The optical system for X rays according to the present invention is a focusing optical system having a plurality of such multilayer reflecting mirrors and can obtain object images by using X rays of a plurality of wavelengths.