A 3D-Printed High Power Nuclear Spin Polarizer

Three-dimensional printing with high-temperature
plastic is used
to enable spin exchange optical pumping (SEOP) and hyperpolarization
of xenon-129 gas. The use of 3D printed structures increases the simplicity
of integration of the following key components with a variable temperature
SEOP probe: (i) in situ NMR circuit operating at
84 kHz (Larmor frequencies of 129Xe and 1H nuclear
spins), (ii) <0.3 nm narrowed 200 W laser source, (iii) in situ high-resolution near-IR spectroscopy, (iv) thermoelectric
temperature control, (v) retroreflection optics, and (vi) optomechanical
alignment system. The rapid prototyping endowed by 3D printing dramatically
reduces production time and expenses while allowing reproducibility
and integration of “off-the-shelf” components and enables
the concept of printing on demand. The utility of this SEOP setup
is demonstrated here to obtain near-unity 129Xe polarization
values in a 0.5 L optical pumping cell, including ∼74 ±
7% at 1000 Torr xenon partial pressure, a record value at such high
Xe density. Values for the 129Xe polarization exponential
build-up rate [(3.63 ± 0.15) × 10–2 min–1] and in-cell 129Xe spin–lattice
relaxation time (T1 = 2.19 ± 0.06
h) for 1000 Torr Xe were in excellent agreement with the ratio of
the gas-phase polarizations for 129Xe and Rb (PRb ∼ 96%). Hyperpolarization-enhanced 129Xe gas imaging was demonstrated with a spherical phantom following
automated gas transfer from the polarizer. Taken together, these results
support the development of a wide range of chemical, biochemical,
material science, and biomedical applications.