Cho HyungJoon, Baugh Jonathan, Ryan Colm A, Cory David G, Ramanathan Chandrasekhar
Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge MA 02139, USA.
J Magn Reson. 2007 Aug;187(2):242-50. doi: 10.1016/j.jmr.2007.04.012. Epub 2007 Apr 30.
Here, we describe the design and performance characteristics of a low temperature probe for dynamic nuclear polarization (DNP) experiments, which is compatible with demanding multiple-pulse experiments. The competing goals of a high-Q microwave cavity to achieve large DNP enhancements and a high efficiency NMR circuit for multiple-pulse control lead to inevitable engineering tradeoffs. We have designed two probes-one with a single-resonance RF circuit and a horn-mirror cavity configuration for the microwaves and a second with a double-resonance RF circuit and a double-horn cavity configuration. The advantage of the design is that the sample is in vacuum, the RF circuits are locally tuned, and the microwave resonator has a large internal volume that is compatible with the use of RF and gradient coils.
在此，我们描述了一种用于动态核极化（DNP）实验的低温探头的设计和性能特征，该探头适用于要求苛刻的多脉冲实验。实现大的DNP增强的高Q值微波腔与用于多脉冲控制的高效NMR电路这两个相互竞争的目标导致了不可避免的工程权衡。我们设计了两种探头——一种具有单共振射频电路和用于微波的喇叭镜腔配置，另一种具有双共振射频电路和双喇叭腔配置。该设计的优点在于样品处于真空中，射频电路进行局部调谐，并且微波谐振器具有较大的内部体积，与射频和梯度线圈的使用兼容。
