开车兜风顺便做个精密测量实验,科学家研发出便携式冷原子重力仪

冷原子重力仪,这个曾经用于执行太空任务的关键仪器,能否有一天也像车载导航系统一样,成为我们日常生活密切相关的部件?

从第一台冷原子重力仪诞生于实验室以来,经过近30年的发展,冷原子已经成为基础物理研究和计量学领域精密重力测量的成熟技术之一。在国内外科学家的共同努力下,冷原子重力仪被不断推广到更为广阔的科学研究和技术应用领域,如基础物理研究中的弱等效原理验证,暗物质暗能量的探索,和计量学领域新的国际单位之中质量单位的确定等。

冷原子重力测量是使用物质波干涉实现对地球重力加速度的测量技术。由于其不存在机械磨损或漂移问题,因而可以用于补充和增强现有的以下落角锥和石英弹簧系统等经典设备为主的重力加速度测量技术。

随着近年来紧凑型冷原子重力仪的迅速发展, 冷原子重力测量技术已经走出实验室。在以城市环境为主的应用场景中,较高的地面振动噪声极大地限制了重力测量的精度。因此,如何提升冷原子重力仪在城市环境中的测量精度就成为推动冷原子重力仪实用化的关键问题。

来自中国科学技术大学的陈帅教授课题组研发了一种基于改进型主动减震平台的可移动紧凑型冷原子重力仪。该重力仪在城市振动噪声较高的环境中实现了高精度的长期静态重力测量,其测量灵敏度和分辨率等性能已达到实验室安静环境中的重力测量水平。该成果于近期发表于Chinese Optics Letters,2020年第18卷第9期 (B. Chen, J. Long and H. Xie et al., A portable atomic gravimeter operating in noisy urban environments).

该冷原子重力仪的可移动性十分优秀。在较近的测量点之间,只需要一到两人即可完成重力仪的运送、架设和测量;同时,该款重力仪也足够紧凑和稳定,可以通过微型面包车实现长距离测量点之间的运输,因而基本满足了野外或城市外场的静态重力测量需求,还可进一步推进到汽车,飞机,轮船等载具上开展振动处理工作。

满足外场静态测量需求的冷原子重力仪具有巨大的商业价值和产业化潜力,在地质灾害检测,惯性导航和重力地图测量等关键领域有着广泛的市场需求。美国和欧洲的初创公司也凭借其未来的应用前景拿到了巨额的国家补贴。在我国,国家和政府投入了大量的经费用于冷原子重力仪的应用研究。相信有一天,冷原子重力仪会像车载导航系统一样走进我们的生活。

可移动冷原子重力仪及其主动减振系统可以方便地实现搬运,并能在高振动噪声环境中进行长期的高精度重力测量

A "Quantum" leap towards gravity survey in noisy urban environments

Atomic gravimetry measures the gravitational acceleration through matter-wave interferometry. As this novel quantum system suffers neither mechanical wear nor drift, it outperforms or strongly enhances the classical devices, such as the falling-corner-cube or spring-mass systems, in gravity survey. Since the very first demonstration in laboratory over 30 years ago, atomic gravimetry has matured to a versatile tool that offers both precise and accurate absolute gravity measurement to fundamental research and metrology, such as testing the weak equivalence principle or linking the mass and weight of the test mass in Kibble balance. In the light of current rapid development of compact cold-atom gravimeters, enormous effort has been made to push atomic gravimetry out of the laboratory to fulfill the demands of geophysics and civil engineering in noisy urban environments, where the vibration noise limits the measurement sensitivity and precision.

Benefit from an improved portable active vibration isolator, the research group led by Prof. Shuai Chen from University of Science and Technology of China develops a compact cold-atom gravimeter that performs precise long-term static gravity measurement in noisy urban environments, of which the sensitivity and resolution are comparable to state-of-the-art in-laboratory devices. The research results are published in Chinese Optics Letters, Volume 18, Issue 9, 2020 (B. Chen, J. Long and H. Xie et al., A portable atomic gravimeter operating in noisy urban environments).

For nearby locations, the cold-atom gravimeter is of notably good mobility, which is easily transferable, erectable and measurable by one or two manpower. Meanwhile, it is also compact and robust enough to be fitted inside a minivan and transported over a long range. It is believed that with the development of applications in geophysics and civil engineering, atomic gravimetry would play a more and more important role in the life of human being.

Benefit from an improved portable active vibration isolator, the portable atomic gravimeter can perform precise long-term static gravity measurement in noisy urban environments, also being with excellent transportability