-
本文针对微弱磁场精密测量问题, 在自主研制的铷-氙气室原子磁力仪系统上, 探讨了两种磁场测量的方式, 分别实现了对交流磁场与静磁场的测量, 并对它们的磁场测量能力进行了实验标定. 交流磁场测量原理是基于测量外磁场对 87Rb原子极化的影响, 实验标定结果为在2100 Hz频率范围内磁场测量的灵敏度约为
$ 1.5\;{{{\rm{pT}}} / {\sqrt {{\rm{Hz}}} }} $ , 带宽约为2.8 kHz; 静磁场测量原理是基于测量铷-氙气室内超极化 129Xe的拉莫进动频率, 实验上首先测得超极化 129Xe的横向、纵向弛豫时间分别约为20.6和21.5 s, 然后通过标定给出静磁场测量精度约为9.4 pT, 测量范围超过50 μT. 相比无自旋交换弛豫原子磁力仪, 该磁力仪在同一体系内实现了交流磁场与静磁场的测量, 且交流磁场测量具有更大的带宽, 静磁场测量可在地磁场下正常工作, 将有望应用于地磁测量、基础物理等方面的研究.The precise measurement of weak magnetic fields by using high-sensitivity magnetometers is not only widely used, but also promotes the development of many research fields. The magnetic field measurement capability of the magnetometer determines the potential and scope of its application, which means that research on its magnetic field measurement capability is essential. In this work, we develop a rubidium-xenon vapor cell atomic magnetometer. The cell filled with 5-torr 129Xe, 250-torr N 2and a droplet of enriched 87Rb is placed in the center of a five-layer magnetic shield with four sets of inner coils to control the internal magnetic field environment. In the cell, 129Xe is polarized by spin exchange collisions with 87Rb atoms, which are pumped with a circularly polarized laser beam at the D 1transition. If magnetic fields or pulses are applied to the cell, the polarization state of 87Rb and 129Xe will change and evolve, whose evolution process can be described by a pair of Bloch equations. The analysis of the Bloch equations indicates that the rubidium-xenon vapor cell atomic magnetometer can measure magnetic fields by two different methods. The magnetic field measurement capabilities of the two methods are experimentally calibrated respectively. The first method is to measure the alternating current (AC) magnetic fields by measuring the influence of the external magnetic fields on the polarization of the 87Rb atoms. The experimental results show that the sensitivity of the AC magnetic field measurement is about $1.5\;{{{\rm{pT}}} / {\sqrt {{\rm{Hz}}} }} $ in a frequency range of 2100 Hz, and the bandwidth is about 2.8 kHz. The second method is to measure the static magnetic fields by measuring the Larmor frequency of the hyperpolarized 129Xe in the cell. Considering that its measurement accuracy is limited by the relaxation of the hyperpolarized 129Xe, the transverse and longitudinal relaxation time are measured to be about 20.6 s and 21.5 s, respectively. Then, the experimental calibration results indicate that the static magnetic field measurement precision is about 9.4 pT and the measurement range exceeds 50 μT, which prove that the static magnetic field measurement can still be performed under geomagnetic field (50 μT). The rubidium-xenon vapor cell atomic magnetometer enables the measurement of AC magnetic fields and static magnetic fields in the same system. Compared with the spin exchange relaxation free (SERF) atomic magnetometer, the rubidium-xenon vapor cell atomic magnetometer has some unique advantages. For AC magnetic field measurement, it has a wider frequency range. For static magnetic field measurement, it can be performed under geomagnetic field and can give the magnetic field measurement value without using the calibration parameters of the system. These characteristics make the rubidium-xenon vapor cell atomic magnetometer have broad application prospects. It is expected to be applied to geomagnetic surveys, basic physics and other aspects of research.[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21] [22] [23] [24] [25] [26] [27] [28] [29] [30] [31] [32] [33] [34] [35] [36] [37] [38] [39] -
[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21] [22] [23] [24] [25] [26] [27] [28] [29] [30] [31] [32] [33] [34] [35] [36] [37] [38] [39]
下载:
计量
- 文章访问数:9265
- PDF下载量:170
- 被引次数:0