Physics with Polarized Helium 3

3 He、21 Ne和129 Ne的极化惰性气体样品提供了 我们多方面计划的工具， 在原子、核和核子尺度上的相互作用。 我们有 从四年前的探索阶段， 大量的3 He首先通过自旋交换极化 用激光光抽运Rb，研制成功 高旋进核磁共振频率光谱和 实现极化的3 He目标。 的技术 我们能够测量自由旋进频率 在一小时的测量间隔内具有10-7 Hz的精度 并对洛伦兹不变性的破坏设定了新的限制， 相对于首选方向的质量各向异性。 一 时间反演不变性的测量 Xe 129的电偶极矩（EDM）正在进行中。 该测量 应在10-27 e-cm的水平上对EDM敏感。 我们 光泵浦和自旋交换机制的研究， 去极化电离理论与测量 利用加速器光束，发展半导体激光器列阵 和新光源的探索使得 极化~ 3 He作为中子靶的实际应用 极化和加速器实验。 我们现在处于 在麻省理工学院贝茨LINAC建立实验的过程， 测量中子的电形状因子， 极化电子与极化~ 3 He的弹性散射。 我们还将证明扩大目标的可行性 为了测量中子的自旋相关结构 极化电子深度非弹性散射函数 从极化3 He在SLAC的意图， 尽快测量。

Polarized noble gas samples of 3He, 21Ne and 129Xe provide tools for our multifaceted program investigating fundamental interactions at the atomic, nuclear and nucleon scale. We have advanced from the exploratory stage of four years ago, when large quantities of 3He were first polarized by spin exchange with laser optically pumped Rb, to the successful development of high precession NMR frequency spectroscopy and the realization of polarized 3He targets. With the techniques developed, we are able to measure free precession frequencies with a precision of 10-7 Hz in a one hour measurement interval and have set new limits on Lorentz Invariance violation due to Mass Anisotropy with respect to a preferred direction. A measurement of the time reversal invariance violating electric dipole moment (EDM) of Xe129 is underway. This measurement should be sensitive to the EDM at a level of 10-27 e-cm. Our study of the optical pumping and spin exchange mechanisms, theory and measurement of depolarization including ionization by the accelerator beam, the development of diode laser arrays and exploration of new light sources have made possible the practical application of polarized 3He as a target for neutron polarization and accelerator experiments. We are now in the process of building an experiment at the MIT Bates LINAC to measure the electric form factor of the neutron by quasi- elastic scattering of polarized electrons from polarized 3He. We will also demonstrate the feasibility of a scaled up target for a measurement of the neutron's spin dependent structure function by deep inelastic scattering of polarized electrons from polarized 3He at SLAC with the intent of undertaking that measurement as soon as possible.