| 摘要 |
<p>PROBLEM TO BE SOLVED: To measure the density of a stratum by a method wherein a high- energy pulse neutron source is shone at the stratum from the inside of a bore hole and gamma rays generated due to the irradiation of the non-ballistic scattering of neutrons by oxygen atoms inside the stratum are detected and analyzed. SOLUTION: An apparatus is provided with a tool body 10 by which a wire line stratum-detecting tool is lowered into a well so as to detect a stratum, with a wire line cable, with a remote measuring electronic device and with an earth surface installation device. An accelerator neutron source 110 is installed at the inside of the tool body 100. An adjacent detector 130 and a remote detector 140 are arranged by installing a shielding region 120 from it. The respective detectors 130, 140 are provided with scintillator crystals 132, 142, with photomultiplier tubes 134, 144 related to, e.g. GSO and with electronic packages 136, 146 which transmit signals to the surface of the earth for its analysis. When the sensity of the stratum is measured, the intensity of gamma rays detected by making use of gamma rays from oxygen as a secondary source is decided by the atomic density of oxygen in the stratum.</p> |
