基于LaBr3:Ce探测器的241Am-Be中子源测井研究

摘要

Background: The widely used bismuth germanium oxide (BGO) detector has low energy resolution in neutron well logging, and thus cannot meet the requirements of some practical applications. Purpose: This study aims to obtain high energy resolution spectrum using a LaBr3:Ce detector in neutron-gamma logging.Methods: Several common geochemical elements such as H, C and Fe were measured using241Am-Be neutron source with LaBr3:Ce detector in a radioisotope neutron testing well belonging to China Petroleum Group Logging Corporation, and a commonly used BGO detector was employed to provide a comparison with LaBr3:Ce detector under the same well logging test condition.Results: The energy spectrum of LaBr3:Ce detector exhibited higher energy resolution than that of BGO detector, and a clear signal of Fe whilst a very weak Fe signal in energy spectrum of LaBr3:Ce detector. Conclusion:The application of LaBr3:Ce detector in nuclear logging has a promising prospect.%针对国内中子测井所使用探测器探测效率不能满足实际应用的情况,采用241Am-Be中子源和LaBr3:Ce探测器在中石油公司一个放射性同位素中子测试井中对H、C、Fe等几种地壳元素进行了测量,并与现今测井常用的锗酸铋(Bismuth Germanium Oxide,BGO)探测器进行对比测量.测得的能谱结果对比发现,进行地壳元素测量时LaBr3:Ce探测器比BGO探测器具有更高的能量分辨率,并且在相同外部测试条件下BGO探测器探测到Fe峰非常微弱.因此将LaBr3:Ce探测器进一步应用到测井中的市场前景广阔.