A rubidium atomic magnetometer and its magnetic field measurement method

Abstract

The invention discloses a rubidium atomic magnetometer and a magnetic field measuring method. Based on the principle of nonlinear magneto-optic rotation, and through combination of timing control and tracking type frequency locking control, the atomic magnetometer achieves a large dynamic measurement range, high magnetic field sampling rate and high sensitivity. A DSP timing control module controls on-off of an acousto-optic modulator and a radio-frequency signal source in the physical part of the rubidium atomic magnetometer according to timing combination to adjust the magnetic field sampling rate N. The DSP timing control module further controls acquisition triggering of a data acquisition card. A calculation unit gets the Larmor precession frequency (f) through fast Fourier transform with use of a received rubidium atom Larmor precession free relaxation signal, and further calculates the value of an external magnetic field. The calculation unit selects a high magnetic field sampling rate module or a low magnetic field sampling rate module before measurement according to the pre-judged dynamic range of a to-be-measured magnetic field, and sets whether a tracking type frequency locking work mode is used when the low magnetic field sampling rate module is selected. In the working process, data is acquired and processed, and the value of the magnetic field is output.

Description

technical field [0001] The invention belongs to the field of magnetic field measurement, and in particular relates to a rubidium atom magnetometer with a large dynamic measurement range, high magnetic field sampling rate and sensitivity and a magnetic field measurement method thereof. Background technique [0002] In the field of magnetic field measurement, the dynamic measurement range, magnetic field sampling rate and sensitivity of the measuring instrument are three important indicators. At present, Mz and Mx modes of optical pumping magnetometer (optical pumping magnetometer, OPM), coherent population trapping (coherent population trapping, CPT) magnetometer, nonlinear magneto-optical rotation (nonlinearmagneto-optical rotation, NMOR) magnetometer have appeared in the world. Atomic magnetometers, spin-exchange relaxation free (SERF) magnetometers and other atomic magnetometers, "Liu Guobin, Sun Xianping, Gu Sihong, Feng Jiwen, Zhou Xin. Research progress of high-sensitiv...

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Problems solved by technology

American Geometrics Company recently launched the G-824A aviation cesium magnetometer with a measuring range of 20000nT~100000nT and a sensitivity of less than 0.2pT / Hz 1 / 2 RMS, the magnetic field sampling rate can reach 1000Hz. However, China needs to obtain an export license from the United States to import this kind of magnetometer. It is difficult to obtain this kind of magnetometer in the military field in China.

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