本实验室研制了一台专门用于测定溶于地下水岩石圈中的气体He/Ar、N_2/Ar比值的质谱装置。对氦的探测灵敏度小于0.1ppm,精度±0.2%。用该装置对北京两处地下热水进行了连续分析。在邢台发生6.1级地震前半个月He/Ar比值明显增高并持续上升到地震前一周,最高值比正常值高40%,然后逐渐下降到正常值。 The laboratory developed a dedicated mass spectrometer for the determination of gas He / Ar, N 2 / Ar ratios dissolved in groundwater lithosphere. Detection of helium sensitivity of less than 0.1ppm, accuracy of ± 0.2%. With this device, two underground hot water in Beijing were continuously analyzed. During the first half of the 6.1 magnitude earthquake in Xingtai, the He / Ar ratio increased significantly and continued to rise up to 40% of its normal value one week before the earthquake, and then gradually dropped to its normal value.