Patent Number: 052767248
Section: claims

1. An X-ray exposure apparatus comprising: a first vessel for containing a sample to be exposed to an X-ray and means for providing thereto a gaseous atmosphere of a relatively higher pressure;  a second vessel contiguous to said first vessel and maintained at a relatively lower pressure than said first vessel for operating an X-ray generating source connected thereto; and  a window partitioning said first and second vessels, said window being composed of a plurality of juxtaposed substantially straight hollow thin tubes which are joined together in parallel to each other so as to form a plate member having a pair of parallel surfaces formed by end surfaces of said tubes, on which respective ends of said tubes open, whereby X-rays of said generating source may pass through an open surface area of said window from said second vessel to said first vessel, and said tubes of the window restrict flow of gas between said vessels to maintain the first and second vessels at the higher and lower relative pressures respectively. 2. An X-ray exposure apparatus according to claim 1, wherein said first vessel has a pressure P.sub.1 and said second vessel has a pressure P.sub.2 (where P.sub.1 &gt;P.sub.2), said window is composed of a number n of thin tubes and each of said hollow thin tubes has an inner diameter D and a length L selected to provide gas conductance of C.sub.o such that gas flow through the window is G.gtoreq.nC.sub.o, so as to allow the pressure of said second vessel evacuated by a pump having an evacuation rate G to be maintained to said pressure P.sub.2 or below. 3. An X-ray exposure apparatus according to claim 1, wherein each of said joined thin tubes is formed to taper in such a manner that an inner diameter thereof gradually decreases in a direction from said second vessel to said first vessel, an inner surface of said thin tube being coated by a material having a high X-ray reflectance. 4. An X-ray exposure apparatus according to claim 1, wherein said window has side dimensions of several tens of millimeters and the open surface area ratio provided by said hollow thin tubes is substantially 63% of said window area. 5. An X-ray exposure apparatus according to claim 4, wherein said thin tubes have an inner diameter D of substantially 6 to 25 .mu.m and a length L of substantially 0.5 mm to 2.0 mm, and said window has dimensions of substantially 30 mm.times.30 mm.