Production of HyperpolarizedH2Molecules from

R. Engels

¹

,

M. Gaisser

²

,

Robert Gorski

³

et al.

Abstract

The preservation of the nuclear polarization of hydrogen atoms during the recombination to molecules was observed on different surface materials in the temperature range from 45 to 100 K and for magnetic fields up to 1 T. On a gold and a fused quartz surface, the expected molecular polarization of about 50% or lower of the atomic polarization was measured, while a surface layer of perfluoropolyether (Fomblin) shows a nearly complete preservation (at least 97%) of the atomic polarization during the recombination process. Further experiments have the possibility of storing polarized deuterium molecules and to use them in nuclear-fusion installations. Another application might be the production of polarized substances for enhanced NMR techniques.

Production of HD Molecules in Definite Hyperfine Substates

“…With this setup it was possible to produce polarized H 2 and D 2 molecules with parallel nuclear spins. Depending on the surface materials large polarization values above 0.8 have been obtained [12]. Hydrogen molecules are a combination of fermions and exist as ortho-hydrogen, where both nuclear spins are coupled to a total spin F = I 1 + I 2 = 1, and para-hydrogen with F = 0.…”

Highly Nuclear-Spin-Polarized Deuterium Atoms from the UV Photodissociation of Deuterium Iodide

“…Polarized solid deuterium targets can be produced where the densities can reach as high as 2.5 × 10 19 spins/cm 3 , albeit in much lower polarization close to 10% [13]. Another approach for the production of polarized sold fuel involves accumulating the hyperpolarized deuterium in specially coated storage cells [11].Laser photodissociation of hydrogen halides has been shown to produce highly polarized H atoms [14][15][16][17]. The photodissociation process initially polarizes the electron spin up to 100% (for photofragment velocities parallel to the propagation direction of the circularly-polarized dissociation laser) [18]; due to the hyperfine interaction, the polarization oscillates back and forth between the electronic and the nuclear spin on the ∼1-ns timescale.…”

“…Polarized solid deuterium targets can be produced where the densities can reach as high as 2.5 × 10 19 spins/cm 3 , albeit in much lower polarization close to 10% [13]. Another approach for the production of polarized sold fuel involves accumulating the hyperpolarized deuterium in specially coated storage cells [11].…”

“…The technical challenges of measuring fusion polarization dynamics limits the number of experiments which pursue this direction to two facility-scale experiments [11]. These experiments achieve nuclear spin polarization by magnetically separating the nuclear spin states via the Stern-Gerlach effect in molecular beams, a process however which limits the achievable production rates to ∼ 10 16 atoms s −1 [2], and the projected D-D fusion reaction rate to as low as ∼0.01 neutrons s −1 [12].…”

“…Another approach for the production of polarized sold fuel involves accumulating the hyperpolarized deuterium in specially coated storage cells [11].…”