论文标题
超极化通过零场和低场状态的快速旋转场读书
Hyperpolarization read-out through rapidly rotating fields in the zero- and low-field regime
论文作者
论文摘要
Para-Hydragen诱导极化（PHIP）方法的整体组成部分是将核单重序转换为可观察的磁化。在这项研究中，通过由旋转磁场和弱偏置场的组合驱动的质子单线态态的选择性旋转来实现极化转移到异核。出乎意料的是，我们发现在存在$μ$ t偏置场的情况下，由风暴驱动的有效极化转移（通过旋转磁场通过旋转磁场振荡）脉冲需要旋转频率，以几个kHz的速度旋转频率。因此，旋转频率大大超过了典型的零和超低场实验的任何内部频率。我们进一步表明，旋转场的旋转方向不是任意的，并且极大地影响了最终转移效率。通过考虑超极化（1- $^{13} $ c）富马酸盐，通过实验证明了其中一些方面。此外，我们还提供数值模拟，突出了暴风雨脉冲与破坏性四极耦合伙伴的弹性。因此，与大多数现有方法相反，风暴程序代表了在PHIP实验中四耦合极化转移的有前途的候选者。
An integral part of para-hydrogen induced polarization (PHIP) methods is the conversion of nuclear singlet order into observable magnetization. In this study polarisation transfer to a heteronucleus is achieved through a selective rotation of the proton singlet-triplet states driven by a combination of a rotating magnetic field and a weak bias field. Surprisingly we find that efficient polarisation transfer driven by a STORM (Singlet-Triplet Oscillations through Rotating Magnetic fields) pulse in the presence of $μ$T bias fields requires rotation frequencies on the order of several kHz. The rotation frequencies therefore greatly exceed any of the internal frequencies of typical zero- to ultralow field experiments. We further show that the rotational direction of the rotating field is not arbitrary and greatly influences the final transfer efficiency. Some of these aspects are demonstrated experimentally by considering hyperpolarised (1-$^{13}$C)fumarate. In addition, we provide numerical simulations highlighting the resilience of the STORM pulse against disruptive quadrupolar coupling partners. In contrast to most of the existing methods, the STORM procedure therefore represents a promising candidate for quadrupolar decoupled polarisation transfer in PHIP experiments.
