成人の広汎性発達障害における補助診断ツールの意義 (特集 大人において広汎性発達障害をどう診断するか)

Abstract

We demonstrate the measurement of the transverse spin relaxation rate of Xe without the influence of the Rb polarization-induced magnetic field gradient. The optical pumping beam and probe beam turn on and off repeatedly during the measurement to reduce the relaxation originating from the Rb polarization-induced magnetic field gradient. During the absence of the optical pumping beam, the nuclear spin of the noble gas atom does not experience the alkali-polarization-induced magnetic field gradient so that the transverse spin relaxation rate (1/T₂) decreases. When the duty cycle reaches zero, the measured transverse relaxation time T₂ approaches the longitudinal spin relaxation time T₁. Our method helps in roughly estimating the longitudinal spin relaxation time with a single measurement of the free induction decay.