基于同步自旋交换光泵浦核磁共振振子的动力学仿真和磁场系统研究

Currently, Domestic and international researches on spin-exchange optical pumping nuclear magnetic resonance gyroscope are based on axial polarized nuclear magnetic resonance oscillator. In this kind of oscillator, we have pumping laser polarized along the same axes as bias magnetic field. Polarized alkali atoms collision with noble gas atoms, resulting in an effective magnetic field on noble gas. This effective field will lower the stability of noble gas precession, then limit precision of a gyroscope. In order to overcome this, some scientists developed a new synchronous spin-exchange optical pumping nuclear magnetic resonance oscillator. In the new oscillator, the pumping laser is arranged perpendicular to the bias field, so the polarization of alkali atoms are also perpendicular to the bias field. With adjustment of pumping laser polarization direction variation frequency and repetition frequency of 2pi pulse bias magnetic field, we can synchronize the precession of alkali atoms and noble gas atoms. And they got very good experiments results. In this program, I want to concentrate on the incomplete description of the oscillator dynamics and the rough design of magnetic field coil and control system. This program aims to develop equations which take into consideration of the coupling between alkali atoms and noble gas, and to design magnetic coils(without magnetic momentum) and its control system. At last we want to set up a synchronous spin-exchange optical pumping nuclear magnetic resonance oscillator with updated researches and studies, in order to reach higher precise oscillator.

目前国际国内主流自旋交换光泵浦核磁共振陀螺的核心为纵向极化核磁共振振子，其泵浦光与偏置磁场同向。极化的碱金属原子将产生有效磁场叠加到偏置磁场中，影响稀有气体原子核进动频率的稳定性，限制核磁共振陀螺的精度。针对此问题，国外同行提出了全新的同步自旋交换光泵浦核磁共振振子。新振子采用横向泵浦光极化碱金属原子，通过调节泵浦光的泵浦方向配合碱金属2π脉冲偏置磁场重复频率，实现碱金属原子和稀有气体原子同步进动，得到了较好的实验效果。本项目重点针对该振子目前动力学理论不完善、磁场控制系统太粗糙等两方面开展研究，力图将碱金属原子和稀有气体原子的动力学耦合考虑进来，完善动力学模型；设计适合新振子的无磁矩线圈及磁场控制系统，并搭建多方面优化的新振子实验系统，期望实现高精度同步自旋交换光泵浦核磁共振振子。

新的同步自旋交换光泵浦核磁共振振子采用横向泵浦光极化碱金属原子，通过调节泵浦光的泵浦方向配合碱金属2π脉冲偏置磁场重复频率，实现碱金属原子和稀有气体原子同步进动，有望降低纵向碱金属原子极化引入的系统误差。项目重点针对该振子目前动力学理论不完善、磁场控制系统太粗糙等两方面开展研究。将碱金属原子和稀有气体原子的动力学耦合考虑进来，得到完善的动力学模型并实现高效率仿真程序；分析了不同无磁矩线圈的性质，设计了适合新振子的线圈系统及其驱动电路；利用无磁矩线圈及磁场控制系统，搭建多方面优化的新振子实验系统，得到共振信号，实现新型振子及同步光泵浦磁力仪的验证，为下一步提升新振子的性能及开发其应用提供基础。项目研究中对温度测量、磁场设计、闭环相位移动设置和频率获取算法等方面提出了新的思路，得到较好的效果。这些技术具有较强通用性，可应用于其它精密测控系统。期间已经发表sci论文1篇，发明专利1项。