Hyperpolarized Xe atoms and atomic magnetometer for the detection of ultralow magnetic field

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The target of this research project is to develop the precise atomic magnetometer with the hybrid setup of spin-polarized Xe and Rb atoms. To utilize Xe atoms with intrinsically-long spin-relaxation time, it is necessary to preserve atoms at high density for a long time without loss of spin-polarization. I came up with the idea to solvate the hyperpolarized Xe atoms in some liquid where much higher density can be realized as gas phase at normal condition. The mechanism of spin-relaxation in solution, nuclear dipole interaction and spin-rotation interaction with solvent molecules, as well as wall relaxation was found. Wall relaxation is mostly dominant in spin-relaxation process since enormous numbers of past works cleared up the relaxation mechanism in gas-phase. We would get extremely high polarization of gaseous atoms if we overcame the wall relaxation. Our high field NMR measurement is one of hopes to lead us to understand the spin interaction at the walls. We are able to regenerate phase diagram of metal-impurities alloy by detecting Knight shift near the melting points of pure metal. Then, we assigned that two species of impurities can solve in alkali-metal in the glass cells. One is oxygen atoms. Once oxygen atoms solved into alkali-metal, the trace oxygen homogeneously takes electron from conduction band of metal. Since the electron density at surface is related to the nuclear spin relaxation of ^3He atoms, our finding gave as the technique to control precisely the oxygen density and to develop novel coating materials on the glass surface. In addition to wall relaxation mentioned above, we discovered the new phenomenon that the angular momentum can be transferred to a solid. By optically pumping gaseous Cs atoms, Cs nuclei of CsH salt was found to be polarized as 19-times as thermal equilibrium at 2.7T and 100℃.