2024/11/18 by Fasong Zheng, Zheng, Fasong, Weiliang Chen +11
Decision Sciences · Physics and Astronomy · #Advanced Frequency and Time Standards #Atomic Physics (physics.atom-ph) #FOS: Physical sciences #Quantum Physics (quant-ph) #Radioactive Decay and Measurement Techniques #Scientific Measurement and Uncertainty Evaluation
paper · pdf · doi:10.48550/arxiv.2411.11349
openalex publication_date 2024/11/18 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
A new caesium (Cs) fountain clock NIM6 has been developed at the National Institute of Metrology (NIM) in China, for which a comprehensive uncertainty evaluation is presented. A three-dimensional magneto-optical trap (3D MOT) loading optical molasses is employed to obtain more cold atoms rapidly and efficiently with a tunable, uniform density distribution. A heat pipe surrounding the flight tube maintains a consistent and stable temperature within the interrogation region. Additionally, a Ramsey cavity with four azimuthally distribution feeds is utilized to mitigate distributed cavity phase shifts. The Cs fountain clock NIM6 achieves a short-term stability of 1.0x10-13 τ-1/2 at high atomic density, and a typical overall fractional type-B uncertainty is estimated to be 2.3x10-16. Comparisons of frequency between the Cs fountain NIM6 and other Cs fountain Primary Frequency Standards (PFSs) through Coordinated Universal Time (UTC) have demonstrated an agreement within the stated uncertainties.