Four-Section Gas Detector Designed for the Multispaced Neutron Logging Tool

摘要

A four-section gas detector is designed for a multispaced neutron logging tool. The detector has a cylindrical structure filled with a gas agent common to all sections. It consists of four galvanically isolated cathode sections which have a common axisymmetric anode line. Depending on gas composition and high voltage the detector may operate in two modes: proportional and corona. The detector can be connected in two ways. In the case when signals are taken from the cathodes of the sections and transmitted to separate amplifier and data-processing circuits, the detecot may operate both in the corona and proportional modes. If the signal is taken from the common anode, the detector may operate in the proportional mode only. In that case, data belonging to different sections are separated using a low-voltage bias of signals produced by different cathode sections. This method provides a reliable resolution of peaks of the resulting differential spectrum. In that case, a common amplifying and data-processing channel is applied.