| 摘要 |
PURPOSE:To suppress the radiation dose corresponding to an L level and drift and to decrease measurement errors by providing a shielding cylinder having an aluminum mirror surface on the inside surface between a modulator having aluminum mirror surfaces on both sides and a detector. CONSTITUTION:The aluminum mirror surface having low emissivity is formed on the surface of the vane of the modulator 2 on the detector side and the aluminum mirror surface having high emissivity is formed on the surface on the side of an object to be measured. The shielding cylinder 5 is provided in the space from the vane part of the modulator 2 to the detector 3 in such a manner that the detector 3 exists at the end of the cylinder inside and that the modulator 2 exists in proximity to the other end. The inside circumferential surface of the cylinder 5 is made into the mirror surface of aluminum having low emissivity. As a result, the visual field viewed from the detector 3 side is totally closed when the shielding part of the modulator 2 exists in the corresponding position of the aperture of the cylinder 5. The entry of the external light to the detector 3 is thus eliminated and the influence of IR rays and temp. change is decreased by the low emissivity inside surface of the cylinder 5. |
