| 摘要 |
PURPOSE:To secure high precision by determining the two-dimensional distribution of the concentration of a nuclear fuel substance on an object surface while determining the transmittivity of a photon by measuring the strength thereof before and after it is transmitted through a sample, and by correcting neutron strength data by this transmittivity. CONSTITUTION:First a moving mechanism 4 being set in an initial state, an object surface of measurement of a sample 2 for measurement is selected by an elevating truck 6 and set, while a horizontal running truck 5 and a sample loading truck 7 are set at measurement starting positions, and a photon ray is applied to the sample 2. A fast neutron emitted by the application of the photon ray is moderated by a neutron moderator 10 to be a thermal neutron, which is then detected by a neutron detector 11. Next, a straight-run scan is executed in the prescribed number of times ((m) times), and after the straight-run scan in (m) times is completed, rotary shift is executed in the prescribed number of times ((n) times). Based on data in the number of (m)X(n) thus obtained, subsequently, an image is restructured and thus the two-dimensional distribution of the concentration of a nuclear fuel substance is obtained. Besides, the transmittivity of a photon is determined by measuring the strength of the photon before and after it is transmitted through the sample 2, and neutron strength data is corrected by the detector 11 on the basis of this transmittivity. |
