Highly spin-polarized deuterium atoms from the UV dissociation of Deuterium Iodide

TL;DR

This paper demonstrates a method to produce highly spin-polarized deuterium atoms via UV photodissociation of deuterium iodide, achieving high densities suitable for fusion research.

Contribution

It introduces a novel photodissociation technique to generate hyperpolarized deuterium atoms at densities much higher than traditional methods.

Findings

Achieved near 100% electronic polarization of deuterium atoms.

Converted electronic polarization to about 60% nuclear D polarization within 1.6 ns.

Produced hyperpolarized deuterium densities of ~10^18 cm^-3, enabling fusion experiments.

Abstract

We report the production of highly spin-polarized Deuterium atoms via photodissociation of deuterium iodide at 270 nm. The velocity distribution of both the deuterium and iodine photodissociation products is performed via velocity mapping slice-imaging. Additionally, the angular momentum polarization of the iodine products is studied using polarization-sensitive ionization schemes. The results are consistent with excitation of the $A^1\Pi_1$ state followed by adiabatic dissociation. The process produces $\sim$100\% electronically polarized deuterium atoms at the time of dissociation, which is then converted to $\sim 60\%$ nuclear D polarization after $\sim 1.6$ ns. These production times for hyperpolarized deuterium allow collision-limited densities of $\sim 10^{18}$ cm$^{-3}$, which is $\sim 10^6$ times higher than conventional (Stern-Gerlach separation) methods. We discuss how such high-density hyperpolarized deuterium atoms can be combined with laser fusion to measure polarized D-D fusion cross sections.