关键词: 
彭宁阱 /
质量测量 /
四极电场 /
电极电压

摘要: 彭宁阱是用于直接测量原子核质量的精确设备。为了保证彭宁阱的测量精度，需在阱中心产生精准的四极静电场，而四极静电场是通过对彭宁阱的核心电极施加合适的电压产生的。采用公式推导法和最小二乘法两种方法计算得到了LPT核心电极需加电压幅值。对于公式推导法，电压值完全从理论出发，经公式推导后计算得到；最小二乘法的出发点是使取样偏差的平方和最小，且通过仿真模拟考虑了电极的实际几何形状。由这两种方法得到的非四极项系数C4 和C6，可用于估算因偏离理想四极电场所产生的实验误差。虽然这两种方法的出发点不同，但都可以在阱中心产生需要的四极电场。Penning trap mass spectrometry is one of the direct methods and maybe the most accurate tool for atomic mass measurements. The quadrupole electric eld produced in the trap should be very accurate in order to ensure the precision of measurements. The optimal amplitudes for the key electrodes of the Lanzhou Penning Trap(LPT) have been calculated by two methods|formula derivation and least-squares tting. For formula derivation method, the optimal values are based on the theory and deduced from the formulas. Least-squares tting method is to minimize the quadratic sum of sampling deviations, where the actual geometry of the electrodes has been considered by the simulation. The obtained C4 and C6 values can be used to estimate the experimental error produced by the deviation from the ideal quadrupole electric eld. The expected quadrupole electric led could be gotten by both methods.