Source: Chinese Academy of Sciences
Project: Ultralow field laser-detect magnetic resonance instrument with high sensitivity
Chief Specialist: Prof. Xianping Sun
Introduction: Improve of the signal detection sensitivity of the Nuclear Magnetic Resonance (NMR) spectroscopy and Magnetic Resonance Imaging (MRI) have been one of the core research fields of magnetic resonance. Since the magnetic resonance technology had been invented for over 60 years, it received the Nobel Prizes for physics, chemistry, physiology and medicine, respectively. But all commercial NMR and MRI Spectrometer are use RF induction coil to detect the NMR signals.
Because of the poor sensitivity of the RF induction coil, it usually need high field superconducting magnet to obtain enough observed signals. However, as the magnetic field intensity increase, inhomogeneity of the magnetic field is more and more serious, and lead to the signal distortion. As an example, the high field MRI can not be used for the person that implanted devices (such as pacemakers) in vivo. On the other hand, the actual environment of the usual chemical sample and biological tissue is the earth magnetic field (0.000045T), so the effect of the high field intensity that NMR and MRI measurements required on molecular dynamics and human tissues needs to be further researched urgently. So, in order to study the characteristics of molecular samples and human tissue in the actual environment，we can only use the ultralow magnetic field (earth magnetic field to zero magnetic field) NMR and MRI, but the detect technology of the conventional RF induction coil can not obtain magnetic resonance signal. So, this project brings forward a new laser detect NMR instrument with high sensitive, uses to overcome the core problems of NMR in the ultralow magnetic field, also provide technical accumulation for ultralow field MRI.
The laser-detect NMR method base on high sensitivity atomic magnetometer, that no longer need the RF induction coil to obtain NMR signals, not only improves the detecting sensitivity, also get rid of the dependence on the expensive, huge, low-temperature superconducting magnet. This project will developed an atomic magnetometer with the laser-detect NMR sensitivity of 0.2 pT/Hz1/2 base on the interaction phenomenon of laser and alkali metal atom and implementation, and realize ultralow magnetic field (<50nT) NMR spectrometer with signal-to-noise ratio >12 (proton in water, single shot) and line width <0.35 Hz. This instrument will applied to the NMR study of organic chemistry, meanwhile, provide a common experiment platform to study high sensitive NMR under ultralow magnet field.
