| 摘要 |
PURPOSE:To enable conditions of vessel change to be simulated effectively without providing water to the vessel in a bar-shaped detection system by mounting an axis to a line source storage part position at both sides of the line source container and then setting the axis to a rotary mechanism and then rotating it forward and backward in reference to the axis. CONSTITUTION:A specific expression is established regarding a detector output between an exposure and a level to be measured and a detector output is obtained as a sum of a dose of gamma rays reaching a part exposed onto a liquid surface and gamma rays reaching through a liquid. Therefore, when an irradiation part of an irradiation beam can be changed arbitrarily in vessel empty state, a change in the liquid face can be handled equivalently. Namely, when a beam region of b0-u0 is displaced to b1-u1 with an irradiation angle theta being constant while maintaining the irradiation angle O to be constant, an equivalent effect where the liquid face is changed from 10 to 11 can be obtained. In the similar manner, by changing the irradiation beam region to b2-u2 and b3-u3, an effect when the liquid face is changed to levels in 12 and 13 can be obtained. |
