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) 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.本研究采用高温塑料三维打印（3D printing）技术，实现了氙-129（xenon-129, ¹²⁹Xe）气体的自旋交换光泵浦（spin exchange optical pumping, SEOP）与超极化。3D打印结构的应用提升了可变温SEOP探针与以下关键组件的集成便捷性：(i) 工作于84 kHz的原位核磁共振（in situ NMR）电路（对应¹²⁹Xe与¹H核自旋的拉莫尔频率），(ii) 高分辨率近红外光谱（high-resolution near-IR spectroscopy），(iv) 热电温度控制（thermoelectric temperature control）系统，(v) 回射光学（retroreflection optics）组件，以及(vi) 光机对准系统（optomechanical alignment system）。3D打印赋予的快速原型制造（rapid prototyping）能力，显著缩短了生产周期并降低了成本，同时支持现成商用组件（off-the-shelf components）的复用与集成，还实现了按需打印（printing on demand）的理念。本研究验证了该SEOP装置的实用性：在0.5 L光泵浦气室中获得了接近全极化的¹²⁹Xe极化值，其中在1000 Torr氙分压下的极化率可达~74 ±7%，这是该高氙密度下的最高纪录。针对1000 Torr氙气，测得的¹²⁹Xe极化指数增长速率[(3.63 ± 0.15) × 10⁻² min⁻¹]与气室内¹²⁹Xe自旋-晶格弛豫时间（spin–lattice relaxation time）T₁=2.19 ± 0.06 h，与¹²⁹Xe与铷（Rb）的气相极化率之比（P_Rb ~96%）高度吻合。通过从极化器自动转移气体至球形体模（phantom），实现了超极化增强型¹²⁹Xe气体成像。综上，上述结果为化学、生化、材料科学及生物医学等多领域的应用开发提供了有力支撑。