Paper
8 September 2015 An improved proton magnetometer for Earth's magnetic field observation
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Abstract
As a precision instrument to measure the earth magnetic field, proton magnetometer is widely used in different fields such as geological survey, buried objects detection and earth field variations. Due to poor signal to noise ratio (SNR) of the system, proton magnetometer suffers from low sensitivity which directly affects the performance. In order to increase the sensitivity, we present an improved proton magnetometer. First, the effect of matching resistance on Q value is discussed to enhance SNR, and high matching resistance has been chosen to improve the Q value of the resonant circuit. Second, noise induced by pre-amplifier is investigated in order to obtain low noise signal, and we adopt the JFET with noise figure less than 0.5dB as the pre-amplifier. Third, by using band-pass filter, low-noise output signal is obtained. Fourth, the method of period measurement based on CPLD is employed to measure frequency of the square wave shaped from the output sinusoidal signal. High precision temperature compensate crystal oscillator (TCXO) has been used to improve the frequency measurement accuracy. Last, experimental data is obtained through field measurements. By calculating the standard deviation, the sensitivity of the improved proton magnetometer is 0.15nT for Earth’s magnetic field observation. Experimental results show that the new magnetometer is sensitive to earth field measurement.
© (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Chengyu Xiao, Shuang Zhang, Xin Guo, and Haoyang Fu "An improved proton magnetometer for Earth's magnetic field observation", Proc. SPIE 9607, Earth Observing Systems XX, 960729 (8 September 2015); https://doi.org/10.1117/12.2187385
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Cited by 3 scholarly publications.
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KEYWORDS
Magnetometers

Magnetism

Signal to noise ratio

Sensors

Bandpass filters

Resistors

Amplifiers

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