本文叙述了低本底α计数器的结构、调试和性能。该计数器包括三个金硅面垒型半导体探测器(直径为16毫米)和相应的电子学线路,能够同时测量三个样品。它们对~(239)Puα源的效率在30%以上(4π,源的活性区直径为7毫米,源到探测器的距离为2—3毫米),平均本底计数率小于2计数/24小时。 This article describes the structure, debug and performance of a low background alpha counter. The counter includes three gold-silicon surface barrier type semiconductor detectors (16 mm in diameter) and corresponding electronics, capable of measuring three samples simultaneously. They have an efficiency of over 30% for the source of (239) Puα (4π, source active area diameter of 7 mm, source to detector distance of 2-3 mm) and an average background count rate of less than 2 counts per 24 hours .