High-resolution frequency measurement of the ground-state hyperfine splitting of 113Cd+ ions
作者单位：Joint Institute for Measurement Science Tsinghua University Department of Physics Tsinghua University The state key lab of precision Measurement Technology and InstrumentDepartment of Precision Instruments Tsinghua University
会议名称：《第四届中国卫星导航学术年会》
会议日期：2013年
学科分类：08[工学] 080401[工学-精密仪器及机械] 081105[工学-导航、制导与控制] 0804[工学-仪器科学与技术] 0825[工学-航空宇航科学与技术] 0811[工学-控制科学与工程]
关 键 词：microwave atomic clock ion trap hyperfine splitting 113Cd+ ions
摘 要：Time-keeping clock is one of the most important parts in COMPASS global navigation satellite system （GNSS） of China and the synchronization of these time-keeping clocks is the basis of GNSS. Recently, we have engaged in developing a transportable atomic clock based on 113Cd+ ions, which is potentially applied in the comparison of atomic clocks in different locations, including the time-keeping clocks at the ground stations of the COMPASS system. To operate a high precision microwave atomic clock, one has to measure its clock transition frequency precisely at zero external magnetic field. In this paper, the progress of the precision measurement of the ground-state hyperfine splitting of laser-cooled 113Cd+ ions is reported. In the previous experiment, the hyperfine splitting was measured to be 15 199 862 854.96（12） Hz, using Ramsey’s separated oscillation fields technique. Recently, by upgrading the ion trap apparatus, the control time sequence, and the magnetic field stabilization, we obtained a preliminary improved result of 15 199 862 855.013 Hz. This value is nearly one order of magnitude more accurate than the results obtained before.