Patent Number: 
Section: description

First Embodiment FIG. 1 shows an embodiment of an X-ray condenser according to the present invention. In FIG. 1, the X-ray condenser 16 includes an air-tight casing 21, in which a parallel type parabolic reflection mirror 17 functioning as parallel beam forming means as well as parabolic parallel beam forming means, an analyzing crystal 18 as spectrometry means and a zone plate 19 are arranged, and an evacuator 22 for evacuating an interior of the casing 21. The casing 21 is formed of a structural material such as, for example, stainless steal which has sufficient mechanical strength and, preferably, easiness of machining. Although the casing 21 is shown in FIG. 1 as a rectangular box defined by a chain line, its configuration is selected suitably for the respective optical components contained therein and the arrangement thereof. The parallel type parabolic reflection mirror 17 is constructed by juxtaposing a pair of parabolic reflection mirrors 1a each shown in FIG. 2(a) and obtained by machining an X-ray reflection surface of a suitable member 2 to a parabolic surface H in such a way that the parabolic surfaces H make a right angle to each other. When a diverging X-ray R0 incident on the parallel type parabolic reflection mirror 17, horizontally and vertically diverging components of the X-ray R0 are made horizontally and vertically parallel beams, respectively, resulting in a parallel X-ray beam R2 having a rectangular cross section. As well known, the analyzing crystal 18 functions to pick up only a specific wavelength component of X-ray containing a plurality of X-ray components having different wavelengths. A material of the analyzing crystal 18 is selected according to a wavelength of X-ray component to be picked up. The zone plate 19 is constructed by alternately laminating X-ray transmitting bands 12 and X-ray shielding bands 13 as shown in FIGS. 4(a) and 4(b) and functions to condense an incident parallel X-ray beam to a small condensing spot P. In the X-ray condenser 16 constructed as mentioned above, the diverging X-ray R0 from the X-ray source F is taken in the casing 21, which is evacuated by the evacuator 22. In this embodiment in which the parallel type parabolic reflection mirror 17 is used as the parallel beam forming means, it is preferable to use a point focus X-ray source for radiating X-ray from a substantially square focus spot as the X-ray source F. Since the point focus X-ray source radiates X-ray diverging substantially uniformly in the horizontal and vertical directions, the diverging X-ray can be efficiently converted into parallel X-ray beam by the parallel type parabolic reflection mirror 17. The X-ray taken in the casing 21 is shaped to the parallel X-ray beam R2 having the rectangular cross section by the parallel type parabolic reflection mirror 17 and incident on the analyzing crystal 18. The analyzing crystal 18 performs monochromatisation of the incident X-ray to pick up X-ray component having a specific wavelength and directs the monochromatic X-ray to the zone plate 19. Since the zone plate 19 functions to condense parallel X-ray beams to a specific point, the monochromatic parallel X-ray beam incident on the zone plate 19 is condensed to the small condensing spot P. In this case, since X-ray received by the zone plate 19 is the exactly parallel X-ray formed by the parallel type parabolic reflection mirror 17, the size of the condensing spot P resulting from the zone plate 19 is substantially smaller than that achievable by the conventional condenser. According to the present X-ray condenser, it is possible to make the diameter of the condensing spot P as small as 10 xcexcm or smaller, which cannot be achieved by the conventional condenser. Further, in this embodiment, the parallel X-ray beam R2 formed by the parallel type parabolic reflection mirror 17 is made monochromatic by the analyzing crystal 18 and, then, the monochromatic X-ray is directed to the zone plate 19. Assuming that the X-ray incident on the zone plate 19 is continuous X-rays containing a plurality of X-ray components having different wavelengths, there may be blur in the condensing spot P formed by the zone plate 19 due to chromatic aberration, so that it becomes impossible to obtain a well defined condensing spot P having very small area. According to the present invention, however, the parallel X-ray beam incident on the zone plate 19 is made monochromatic by the analyzing crystal 18. Therefore, the influence of chromatic aberration can be reduced and, so, it is possible to obtain a well defined, very small condensing spot P. Since the evacuator 22 discharges air out of the casing 21 in this embodiment, the X-ray is prevented from being reduced in intensity due to air scattering to thereby condense the intense X-ray to a micro spot. In the embodiment shown in FIG. 1, the parallel type parabolic reflection mirror 17 having the structure including the horizontal and vertical parabolic reflection mirrors 1a arranged in parallel is employed as the parallel beam forming means. Instead thereof, it is possible to employ a structure including only one of the horizontal and vertical parabolic reflection mirrors 1a.  As the parallel beam forming means, it is possible to use the parabolic reflection mirror 1b shown in FIG. 2(b) instead of the parabolic reflection mirror 1a shown in FIG. 2(a). The parabolic reflection mirror 1b is constructed with the substrate 3 having a parabolic surface and a metal reflection film 4 formed on the parabolic surface. Alternatively, it is possible to employ a parabolic multi-layered mirror 6 shown in FIG. 3. The parabolic multi-layered mirror 6 is constructed with a substrate 3 having a parabolic surface and a multi-layered film 7 formed on the parabolic surface to reflect X-ray by diffraction. Although, in the embodiment shown in FIG. 1, the analyzing crystal 18 is provided between the parallel type parabolic reflection mirror 17 and the zone plate 19, the analyzing crystal is not always necessary. Further, the evacuation of the casing 21, in which the X-ray path is defined, by means of the evacuator 22 is also not always necessary. The main purpose of the evacuator 22 is to remove air within the casing 21. Therefore, any other means such as a pressure regulator for discharging air or a helium displacing device for displacing air by helium may be used instead of the evacuator 22 so long as the purpose is achieved thereby. Second Embodiment FIG. 5 shows an X-ray micro-diffraction apparatus 23, which is a typical example of application of the X-ray condenser according to the present invention. The X-ray micro-diffraction apparatus 23 is used to analyze the crystal structure of a micro-specimen by irradiating a micro-portion of a specimen or a micro-specimen with X-ray and detecting diffracted X-ray produced in the micro-portion of the specimen, etc. In the X-ray micro-diffraction apparatus 23, a "khgr" axis line is set such that it coincides with a center axis line of X-ray generated from an X-ray source F, that is, the X-ray axis X0 and a "khgr" rotation device 24 is provided on the "khgr" axis line. The "khgr" rotation device 24 rotatably drives a "khgr" arm 26 about the "khgr" axis line. The "khgr" arm 26 supports an xcfx89 rotation device 27, which rotatably drives an xcfx89 arm 28 about an xcfx89 axis line. The xcfx89 axis line is orthogonal to the x axis line, that is, the X-ray axis X0. The xcfx89 arm 28 supports a xcfx86 rotation device 29, which rotates a specimen S about the xcfx86 axis line, that is, the xcfx86 rotation device 29 rotates the specimen S in a plane. The xcfx86 axis line is contained in a plane, which contains the X-ray axis X0 and is orthogonal to the xcfx89 axis line, and passes through a cross point of the xcfx89 axis line and the "khgr" axis line. The specimen S is provided at a cross point of the "khgr" axis line, the xcfx89 axis line and the xcfx86 axis line, which is an irradiation position of an X-ray R3. An X-ray condenser 36 is provided between the X-ray source F and the specimen S. the X-ray condenser 36 functions to condense the X-ray R0 diverging from the X-ray source F to a micro-spot P, which is coincides with a measuring point of the specimen S. The X-ray condenser 36 can be the same as the X-ray condenser 16 shown in FIG. 1. In FIG. 5, a bent PSPC (Position Sensitive Proportional Counter) 31 is provided in a position remote suitably from the specimen S, as an X-ray detector. The PSPC 31 has a position resolution in a center line direction of a PC (Proportional Counter) by detecting a difference in pulse time between opposite ends of the center wire of the PC. In the case shown in FIG. 5, the position resolution is given in a straight direction in a plane orthogonal to the xcfx89 axis line, so that X-rays having different diffraction angles in that straight direction can be detected simultaneously. In the X-ray micro-diffraction apparatus having construction mentioned above, due to the rotation of the specimen S separately about the "khgr" axis line and the xcfx86 axis line, it is possible to make preferred orientation of crystal in disorder condition at the irradiation point of the X-ray R3. Thus, X-rays diffracted at crystal particles are detected by PSPC 31 without omission. Rotation of the specimen S around the xcfx89 axis line is performed in order to adjust an incident angle of X-rays incident on the specimen S and, after the incident angle is set to a predetermined value, for example, 20xc2x0 to 30xc2x0, the position of the specimen S around the xcfx89 axis line is fixed. When the X-ray condenser 36 used in the X-ray micro-diffraction apparatus 23 is the same as the X-ray condenser 16 shown in FIG. 1, it is possible to form a well defined, very small X-ray condensing spot P on a micro-point of the specimen S, as described previously with respect to FIG. 1. Therefore, it is possible to obtain diffracted X-ray information with high spatial resolution from the micro-portion of the specimen S. Incidentally, in the apparatus shown in FIG. 5, the "khgr" axis line is set such that it coincides with the X-ray axis X0 and the xcfx89 rotation system is mounted on the "khgr" rotation system. However, the X-ray micro-diffraction apparatus is not limited to such structure and it is possible to mount the "khgr" rotation system on the xcfx89 rotation system so that the "khgr" axis line is not always coincident with the X-ray axis X0. Third Embodiment FIG. 6 shows an X-ray microscope 32, which is another typical example of application of the X-ray condenser according to the present invention. The X-ray microscope 32 is used to monitor a micro-specimen such as a microorganism by irradiating the micro-specimen with X-ray and measuring X-ray value absorbed by the specimen. The X-ray microscope 32 includes an X-ray condenser 46 for condensing X-rays diverging from an X-ray source F to a condensing spot P, a pinhole 33, an XY stage 34 for supporting a specimen S and a PC 37 as an X-ray detector. For example, the X-ray condenser 46 may be the same as the X-ray condenser 16 shown in FIG. 1. Further, the X-ray condenser 46 and the pinhole 33 are supported by XYZ stages 38a and 38b, which can move an object in parallel in mutually orthogonal three axes, respectively. X-rays diverging from the X-ray source F are condensed to the micro-condensing spot P on the specimen S by the X-ray condenser 46, while restricting unnecessary components such as scattered radiation by the pin-hole 33. X-rays passed through the specimen S are detected by the PC 37 and the value of X-ray absorption is obtained on the basis of the result of detection. The specimen S is moved in a plane orthogonal to the X-ray axis X0 by the XY stage 34 so that the specimen S is swept by a thin X-ray beam. In this case, the spatial resolution of the X-ray microscope depends upon the size of the sweeping X-ray beam. When the X-ray condenser 16 shown in FIG. 1 is used as the X-ray condenser 46, it is possible to condense intense X-ray to the very small condensing spot P to thereby obtain a measuring result of the X-ray microscope with very high spatial resolution. Other Embodiments Although the present invention has been described with reference to the preferred embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments will become apparent to persons skilled in the art upon reference to the description of the invention. It is therefore contemplated that the appended claims will cover any modifications or embodiments as fall within the true scope of the invention. For example, although the X-ray condenser 16 shown in FIG. 1 is used in the X-ray micro-diffraction apparatus 23 shown in FIG. 4 and the X-ray microscope 32 shown in FIG. 6, the X-ray condenser according to the present invention can be applied to other arbitrary apparatuses utilizing X-ray.