NMRG综述：核磁共振陀螺仪的设计原理与应用进展

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本文是一篇关于2010年美国国家标准与技术研究院(National Institute of Standards and Technology, NIST)的IEEE Sensors杂志上的核磁共振陀螺仪(Nuclear Magnetic Resonance Gyroscopes, NMRGs)的综述文章。作者E.A. Donley在文中详尽探讨了核磁共振陀螺仪的工作原理，以及其在旋转检测中的应用。 NMR陀螺仪利用核磁共振现象来测量物体相对于惯性空间的角速度或转动率。这种装置通过检测在特定磁场中核自旋的拉莫尔进动频率变化来实现这一功能。拉莫尔频率是原子核在磁场中自旋运动的固有频率，它与磁场强度和核磁矩有关。当陀螺仪旋转时，由于地球磁场的相对变化，会导致核自旋进动频率发生微小的偏移，这被用来作为旋转角度的指示信号。早期的大型NMR陀螺仪开发于20世纪60年代和70年代，由Singer和Litton等公司制造，其中光学泵浦的NMR陀螺仪尤其引人注目，它们的偏置漂移速度低至每小时0.1°，实现了极高的精度。文章的介绍部分回顾了这些早期工作的历史，包括Karwacki和Woodman等人的先前综述，这些著作为当时的NMR陀螺仪技术奠定了基础。本文深入研究了使NMR陀螺仪成为可能的光谱学技术，包括如何设计和优化磁场，以及如何有效地读取和解析核自旋信号。此外，作者还详细讨论了几种具体设计的NMR陀螺仪，包括它们的结构、材料选择、冷却机制和信号处理方法，这些都是保证高精度测量的关键因素。 NMR陀螺仪的应用广泛，尤其是在导航、航空航天、地震监测和科学研究等领域，对精确度和稳定性有着极高的要求。随着科技的进步，NIST的研究也推动了NMR陀螺仪技术的不断改进，以适应更复杂和精密的环境条件。这篇综述性文章不仅为读者提供了对NMR陀螺仪工作原理的深入了解，而且展示了其技术发展历程和关键设计要素，对于理解现代陀螺仪技术的发展脉络具有重要意义。

Nuclear Magnetic Resonance Gyroscopes

E. A. Donley

Time and Frequency Division

National Institute of Standards and Technology

325 Broadway, Boulder, CO 80305

edonley@boulder.nist.gov

Abstract— Nuclear magnetic resonance gyroscopes (NMRGs)

detect rotation as a shift in the Larmor precession frequency of

nuclear spins. A review of the open literature on NMRGs is

presented, which includes an introduction to the spectroscopic

techniques that enable NMRGs and a discussion of the design

details for several specific NMRGs that have been built.

I. INTRODUCTION

A gyroscope measures the angle or angular rate of

rotation of the object upon which it is mounted relative to

inertial space. Nuclear magnetic resonance gyroscopes

(NMRGs) accomplish rotation detection by measuring a shift

in the Larmor precession frequency of nuclear spins in an

applied magnetic field. Large-scale NMRGs were developed

in the 1960s and 70s, with both Singer and Litton producing

optically pumped NMRGs with bias drifts lower than 0.1 °/h

[1]. Prior to this review article, several other reviews of this

early work had been published. The reviews by Karwacki and

Woodman et al. present detailed specific approaches to

NMRGs [2], [3]. The article by Kuritsky et al. provides a

review of inertial navigation that includes NMRG work

performed through 1983 [4]. The recent review by Liu et al.

presents recent developments in the field of microfabricated

gyroscopes and includes some discussion of NMRGs [5].

Here I attempt to tie together developments in NMRGs

that have occurred over the past 50 years including recent

miniaturization trends. Section II gives an introduction into

the instrumentation and measurement techniques for NMRGs.

Following that, specific examples of NMRGs are given,

including those based on mercury (section III) and on noble

gases (section IV). In section V, studies on nuclear

quadrupolar effects are presented, which cause shifts and

splittings in NMRG spectra. Section VI gives a review of the

comagnetometer approach, which has recently been used to

demonstrate a high-performance NMRG. In section VII,

developments in miniaturization are presented. Apologies are

The views, opinions, and/or findings contained in this

article/presentation are those of the author/presenter and

should not be interpreted as representing the official views or

policies, either expressed or implied, of the Defense

Advanced Research Projects Agency or the Department of

Defense.

(Approved for Public Release, Distribution Unlimited)

given to groups that are not sufficiently credited due to space

limitations or unintentional omissions.

II. T

ECHNICAL BACKGROUND

A simplified version of a typical NMR gyroscope is

presented in Fig. 1. A vapor cell contains one or more active

NMR isotopes such as

129

Xe, an alkali atom such as

Rb, and

some buffer gas. A circularly polarized pump beam resonant

with an optical transition in the Rb atoms and oriented

parallel to an applied field B

spin polarizes the Rb atoms.

The Rb polarization is transferred to the Xe nuclei through

collisions, thereby creating a macroscopic spin polarization

for both species. Coherent spin precession is generated for

both species with applied AC magnetic fields (not shown)

perpendicular to B

. The Xe spins precess about the direction

, with a precession frequency proportional to the magnitude

of the applied field,

. The proportionality constant

is the gyromagnetic ratio,

, which depends on the

properties of the nucleus and is equal to the ratio of its

nuclear magnetic dipole moment to its angular momentum.

The Rb spins precess about the total field, which is the

sum of B

and the field generated by the precessing Xe spins.

Figure 1. The basic elements of an NMR gyroscope. For a discussion of the

various components, see the text.

17 IEEE SENSORS 2010 ConferenceU.S. Government work not protected by U.S. copyright

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