Polarized Xenon Production: Compact Magnetic Field

描述（由申请人提供）：超极化气体，包括氙-129和氦-3，已经证明了它们在肺结构和功能成像以及肺部疾病量化方面的应用。然而，与氦-3相比，氙既便宜又丰富。它较低的扩散常数提供了相对于氦的科学优势，抵消了它较低的回旋磁比的缺点。一种紧凑、坚固、可产生50%偏振度的商用偏振器可用于人体成像，这将引发超偏振氙作为显像剂的广泛研究和应用。UNH小组展示了一种新型的氙气偏振器，它以相对较高的速度和较低的压力沿与激光束相反的方向流动气体混合物。该偏振器在小批量生产时极化率超过60%，生产速度超过每小时4升时极化率超过20%。该偏振器的性能指标（偏振倍生产率）目前超过所有其他偏振器技术一个数量级。单独的STTR项目，以增加可用的激光功率和低温积累能力，将增加偏振器输出的另一个6至10倍。偏振技术依赖于浸没在均匀的25高斯场中的长偏振柱，具有100 ppm均匀度的可调场的核磁共振区域，以及非常强的场积累区。为了使系统紧凑，必须消除这些元素的相互作用。我们的第一阶段STTR项目包括对新型不对称磁导率结构进行数值模拟，以传输、塑造和传播磁场线，从而产生均匀的磁场体积和区域之间的平滑过渡。它还包括原型的制作和测量，以确认仿真和实现之间的一致性。我们完成了数百次设计计算，并制造和表征了2个原型，满足了设计标准。在第二阶段，我们建议进一步完善设计以提高性能，将偏振片组件集成到新的磁环境中，并设计易于访问的内部组件，特别是最终的超极化氙产品。这些发展将把我们的大型实验室原型转变为实用的紧凑型商业医院设备。

DESCRIPTION (provided by applicant): Hyperpolarized gases, both xenon-129 and helium-3, have demonstrated their utility in structural and functional lung imaging and quantifying lung disease. In contrast to helium-3, however, xenon is cheap and abundant. Its lower diffusion constant offers scientific advantages over helium, offsetting the disadvantage of its lower gyromagnetic ratio. Availability of a compact, robust, commercial polarizer producing 50% polarization in useful quantities for human imaging would trigger widespread investigations and applications of hyperpolarized xenon as an imaging agent. The UNH group demonstrated a new type of xenon polarizer that flows the gas mixture at relatively high velocity and low pressure along a direction opposite to the laser beam. This polarizer demonstrated polarization of over 60% for small quantities and 20% for a production rate of over 4 liters per hour. The figure-of-merit (polarization times production rate) of this polarizer presently exceeds all other polarizer technologies by an order of magnitude. Separate STTR projects to increase the useable laser power and to the cryogenic accumulation capacity would increase the polarizer output by another factor of 6 to 10. The polarization technology relies on a long polarization column immersed in a uniform 25 gauss field, an NMR region with adjustable field having 100 ppm uniformity, and a very strong field accumulation region. The interaction of these elements must be eliminated to make the system compact. Our Phase 1 STTR project included numerical simulation of novel asymmetric permeability structures to transport, shape, and spread magnetic field lines creating uniform field volumes and smooth transitions between regions. It also included fabrication of prototypes and measurements confirming the agreement between simulation and realization. We completed several hundred design calculations and fabricated and characterized 2 prototypes, meeting the design critera. In Phase II we propose to further refine the design for improved performance, intergrate the polarizer components into their new magnetic environment, and engineer for ease of access to internal components particularly the final hyperpolarized xenon product. These developments will convert our large laboratory prototype into a practical compact commercially-available hospital-based device.