Broadband Continuous Nuclear Magnetic Resonance Signal in a Pulsed Magnetic Field: Numerical Solutions of Bloch Equations under Radio Frequency Irradiation

Abstract

A novel nuclear magnetic resonance (NMR) experimental scheme is presented, which has promising applications in pulsed magnetic fields. The experimental scheme, broadband continuous wave NMR (BB-CW-NMR), is validated with numerical solutions of Bloch equations in pulsed fields under broadband continuous radio frequency (RF) irradiation. Furthermore, the influence of experimental parameters such as relaxation times and RF power on the waveform and amplitude of the broadband continuous NMR signal is analyzed briefly. To verify the reliability of the numerical calculation program, numerical solutions of the Bloch equations under the irradiation of RF pulse sequence are given. There is good agreement between simulation and expected experimental results, indicating the validity of the program. Finally, we estimate the amplitude of the NMR signal, the level of noise, and RF interference in a BB-CW-NMR experiment. The results of simulation and analysis demonstrate that the BB-CW-NMR experiment scheme is feasible under the conditions of appropriate relaxation times and RF power if the leakage of the RF field into the receiver coil is reduced by at least a factor of 10⁶.