铷原子喷泉钟的误差评估与性能改进
文献类型：学位论文
| 作者 | 杜远博 |
| 学位类别 | 博士 |
| 答辩日期 | 2015 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 魏荣 |
| 关键词 | 铷原子喷泉钟 性能改进 剩余频率漂移 自比对 频率溯源 |
| 其他题名 | Uncertainty evaluation and performance improvements of a Rubidium atomic fountain clock |
| 中文摘要 | 本文介绍在上海光机所量子光学实验室研制的铷原子喷泉钟平台上所做的喷泉钟误差评估与性能改进工作。为了提升喷泉钟的指标，我们对喷泉钟物理系统实施了改造，优化了Ramsey 腔的微波耦合，调低了原子自由飞行区的工作温度，改善了物理系统的磁场和真空环境，以降低相关频移量的不确定度。新的更加稳定的激光器的引入使得喷泉的连续运转时间得到延长，而新的数字电压控制链路的引入降低了恒温控制晶体振荡器输出频率的噪声。在改进之后，在喷泉的特征运行周期中，俘获原子数10^8个，探测到原子数5×10^5个，原子温度达到2μK，测试得到的Ramsey 条纹的信噪比达到246。最终喷泉钟和氢钟比对得到的分数频率稳定度指标达到2.7*10^-13τ^-1/2，在32800 s 积分时间下，稳定度达到1.6×10^-15。 我们的喷泉钟采用本机振荡器锁定模式，在这种运行模式下，晶振的老化会对原子喷泉的频移量有所贡献，即剩余频率漂移，我们评估得到该频移量为-3(2)×10^-16。在误差评估过程中，我们采用了一种被称为自比对的评估方法，它不需要额外的频率参考装置，并且评估结果具有更高的不确定度的评估精度，它适用于分布腔相移、光频移以及冷原子碰撞频移等的评估。 我们采用一系列的手段来提高喷泉钟的可靠性，这延长了喷泉钟的连续运行时间，并使得我们可以开展喷泉钟的频率溯源工作。我们搭建了一套GPS 共视比对装置，实现了喷泉和IGST 的频率比对，在120 000 s 的积分时间下，喷泉和IGST 比对得到的稳定度达到3.5×10^-15，该指标受限于频率传递链路的噪声。而喷泉钟溯源到UTCr 的频率结果与自评估结果也获得了很好的一致性。进一步的准确度评估以及性能改进的工作正在进行中。 |
| 英文摘要 | This dissertation presents the tasks of uncertainty evaluation and performance improvements based on the rubidium atomic fountain clock (AFC). To improve the performance of the AFC and reduce the uncertainty due to the corresponding frequency shift, several improvements were made, including balancing the microwave coupling of the Ramsey cavity, adjusting down the working temperature of the atomic flight region, and optimizing the magnetic and vacuum environment in the physical system. The introduction of a new and more stable diode laser prolongs the continuous running duration, and a new digital control chain is adopted to reduce the noise contribution to the noise of the OCXO frequency output. After the improvements, 10^8 atoms are trapped in the specific fountain cycle, while the number of falling atoms in the detection region is 5*10^5, with the atomic temperature of 2μK, and the signal-to-noise of the Ramsey fringe reaches 246. Ultimately, compared with a local Hmaser, a short-term fractional frequency stability of 2.7*10^-13τ^-1/2 and long-term stability of 1.6*10^-15 at the average time of 32800 s. The local-oscillator locking mode is adopted in our fountain clock, in which mode the aging of the OCXO will contribute to the total systematic bias of the fountain clock, namely residual frequency drift, and the frequency shift is evaluated with the result of -3(2)×10^-16. In the process of accuracy evaluation, we propose a method named as self-evaluation, in which method, an additional frequency reference is not needed, and the evaluation result could reach the better precision uncertainty evaluation. This method applies to the distributed cavity phase shift, light shift, and collisional shift. A series of techniques are introduced to improve the reliability of the atomic fountain, which prolong the continuously running duration and enable the frequency tracing task of the AFC. A Global Positioning System (GPS) common view instrument is constructed to realize the remote requency comparison of the AFC, and a fractional frequency stability of 3.5*10^-15 is achieved at the average time of 120000s by comparing the fountain clock with the IGST, which is limited by the transfer noise. The frequency output of the AFC tracing to the UTCr coincides well with the accuracy evaluation result. The further task of accuracy evaluation and performance improvements is ongoing. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/15945]  |
| 专题 | 上海光学精密机械研究所_学位论文 |
| 推荐引用方式 GB/T 7714 | 杜远博. 铷原子喷泉钟的误差评估与性能改进[D]. 中国科学院上海光学精密机械研究所. 2015. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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