Nuclear magnetic resonance and imaging (NMR/MRI) of optically pumped (OP) hyperpolarized 3He were studied by using a high-c SQUID magnetometer device in microtesla magnetic fields. The OP cell was filled with a few milligrams of Rb metal, 0.0798 bar N2 gas and 0.705 bar 3He gas. The 3He cell had been hyperpolarized at an optical pumping system for 5 ∼ hours first; then it was moved to the SQUID-detected nuclear magnetic resonance and imaging system to measure. An appropriate B1 pulse level and time duration generated a 5° low flip angle of polarization. The free induction decay NMR signals were measured. The spin-lattice relaxation time (T1) of 3He was 4.7 hours.We improved the line width of NMR spectrum to 0.8 Hz by compensating the inhomogeneous gradient field of environment. The filtered back projection image of hyperpolarized 3He could show a clear image in one shot. The SQUID-detected NMR/MRI would be a great interest for biological imaging.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering