Laser Spin-Exchange Polarized 3He and l29Xe for Diagnostics of Gas-Permeable Media with Nuclear Magnetic Resonance Imaging
Abstract
A system to produce large quantities of laser-polarized 129Xe has been developed. A 10 atmosphere gaseous mixture consisting principally of ordinary helium gas, with a few per cent 129Xe and a few per cent nitrogen for quenching, flows through a cell where it is polarized by spin exchange with Rb vapor, which has been optically pumped with a 100 W diode-laser array. The nuclei of the 129Xe atoms become spin-polarized to several tens of per cent during the few minutes they spend passing through the optical pumping cell. After exiting the cell, the gas stream passes through a cold trap, operating at 77 K, where the polarized xenon atoms are accumulated by condensation from the helium and nitrogen carrier gas. We have developed a powerful diagnostic tool to image the spin-polarization of laser-pumped alkali-metal atoms in the optical pumping cell. The images are formed with a weak, transverse probe laser, modulated by alkali-metal atoms, driven by a radiofrequency field to precess at the local Larmor frequency in an inhomogeneous magnetic field.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1997
- Accession Number
- ADA353902
Entities
People
- William Happer
Organizations
- Princeton University