Hyperpolarization of helium-3 through metastable exchange optical pumping at high pressure

通过高压亚稳态交换光泵浦实现氦 3 的超极化

• 批准号: 447624-2013
• 负责人: Vidal, François
• 金额: $ 15.64万
• 依托单位: Institut national de la recherche scientifique
• 依托单位国家: 加拿大
• 项目类别: Strategic Projects - Group
• 财政年份: 2013
• 资助国家: 加拿大
• 起止时间: 2013-01-01 至 2014-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=536935
• 关键词: Hyperpolarization; helium; through; metastable; exchange

Helium-3 is an isotope of the more common element helium (helium-4) which is extracted from the nuclear decay products of tritium. Due to its odd number of nucleons, the nuclei of Helium-3 posses a magnetic moment and its gas can be polarized to a degree of several tens of % (hyper polarization). A gas of helium-3 atoms in the ground state with a high degree of nuclear polarization is highly useful for many applications in different fields such as nuclear physics, materials science, nanotechnology, quantum memory, and biophysics and medicine. In thermal equilibrium, the nuclear polarization of helium-3 induced by only applying a magnetic field is too weak to be useful for many of these applications. However, it is possible to polarize helium-3 to a high degree inside a plasma discharge through optical pumping using a continuous laser. In the so-called "metastability exchange optical pumping process" (MEOP) a nuclear polarization close to 100% can be obtained. However, the current technique operates at a very low pressure (mbar), while most applications require the use of samples of dense and highly polarized helium-3 near atmospheric pressures.The goal of this project is to achieve optimal polarization of helium-3 through MEOP near atmospheric pressure in a moderate magnetic field. This research will be done simultaneously on three fronts, taking advantage of the complementary strengths of our team: (i) the plasma discharge used to generate the helium-3 atomic metastable states that are optically pumped, (ii) relatively high magnetic fields (~ 1 Tesla), and (iii) the numerical modeling, combined with plasma diagnostics, of the excitation and polarization process taking place in the plasma. This project is a collaboration between two universities (INRS and Université de Montréal), a government organization (Atomic Energy of Canada Limited) and an industrial partner (Tyler Research Corporation) specialized in the development and commercialization of high-end medical and scientific instruments.

氦3是从Tritium的核衰减产物中提取的更常见元素氦（氦4）的同位素。由于其奇数的核数，氦-3的核构成了磁矩，其气体可以极化为几十％（超极化）。具有高度核极化的基态的氦3原子的气体对于在不同领域的许多应用（例如核物理学，材料科学，纳米技术，量子记忆以及生物物理学和医学）中非常有用。在热平衡中，仅施加磁场引起的氦3的核极化太弱，无法对许多这些应用有用。但是，可以使用连续激光通过光学泵送在等离子体放电的高度将氦3偏振。在所谓的“亚能交换光学泵浦过程”中（Meop）可以获得接近100％的核极化。但是，当前的技术在非常低的压力（MBAR）下运行，而大多数应用都需要使用密集且高度极化的氦3近大气压的样品。该项目的目标是通过现代磁场中的大气压实现氦3的最佳极化。这项研究将在三个方面同时进行，利用我们团队的完全增强的优势：（i）用于生成光学上泵送的氦3原子可稳态状态的血浆放电，（ii）相对较高的磁场（〜1 tesla），以及（iii）与数值模型相结合，将plasma诊断效果组合在一起。该项目是两所大学（INRS和DeMontréal大学），一个政府组织（加拿大原子能有限公司）与工业合作伙伴（Tyler Research Corporation）之间的合作，专门研究高端医疗和科学工具的开发和商业化。