Method of the super‐highly precise measurement of strong magnetic field (abstract)

摘要

This article describes the method of measuring a strong magnetic field with a nuclear magnetic resonance (NMR) magnetometer using flowing water. In the apparatus, the strong magnetic field measured is taken as the sample of polarizing magnetic field, and frequency synthesizer generator as the source of radio frequency exciting resonance transitions. The apparatus is different from the precise field averaging NMR magnetometer (precision:10-7) for low and high fields using flowing water developed by J. M. Pendlenbury etc., and the wide‐ranged NMR magnetometer (precision:10-5) using flowing water developed by V. M. Simonov and colleagues. The minimum step of the frequency alterations of the synthesizer is 0.01 Hz. The stability of frequency is extremely high. The apparatus can quite accurately measure the proton absorption spectrum of the measured field. This provides possibilities for the super‐high precision measurement of resonance central frequency. The method of taking the arithmetic mean of frequencies  f1 and  f2 measured at the half‐height of spectrum lines to be the measurement of the central frequency  f0 is demonstrated in this paper as well. The precision of measuring results is higher an order of magnitude than that of the direct measurement of  f0. The precision of the measuring results of the value 8.455 T of NMR spectrum superconducting magnetic field reaches 0.7×10-9. This technique can be used to precisely measure the strong magnetic field over 0.5 T. So far as the measurement of the distribution of NMR spectrum superconducting field is concerned, it shows its significant advantages.