| 摘要 |
An aperture device for measuring thin films has an aperture ring, of a material and thickness that is impenetrable by the radiation from radionuclides. The ring has a passage for emitted and reflected radiation extending approximately perpendicular to said ring, and a radiation device consisting of at least one collimating radiation source holder comprising a tube of a predetermined diameter that is permeable to radiation in the forward direction and has sides and a back that are impermeable to radiation and houses a radionuclide. The forward end surface of the tube lies behind the forward end surface of the passage. The cross-section of the passage is large compared to the cross-section of the radionuclide. A partition divides the passage into at least two chambers that are open at their rearward and forward ends. The partition has partition walls that are impermeable to radiation. The radiation source holder is arranged in one of the chambers, the cross-section of which chamber is a multiple of the cross-section of the radiation source holder. The forward end surface of the radiation source holder lies behind the forward end surface of the partition.
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