High Pressure Physics Division, Department of Physics, Adam Mickiewicz University, Umultowska 85 St, 61-614 Poznań, Poland.
J Magn Reson. 2011 Jan;208(1):163-6. doi: 10.1016/j.jmr.2010.10.018. Epub 2010 Nov 5.
This paper reports on design and construction of a double coil high-homogeneity ensuring Nuclear Magnetic Resonance Probe for off-resonance relaxation time measurements. NMR off-resonance experiments pose unique technical problems. Long irradiation can overheat the sample, dephase the spins because of B(1) field inhomogeneity and degrade the signal received by requiring the receiver bandwidth to be broader than that needed for normal experiment. The probe proposed solves these problems by introducing a separate off-resonance irradiation coil which is larger than the receiver coil and is wound up on the dewar tube that separates it from the receiver coil thus also thermally protects the sample from overheating. Large size of the irradiation coil also improves the field homogeneity because as a ratio of the sample diameter to the magnet (coil) diameter increases, the field inhomogeneity also increases (Blümich et al., 2008) [1]. The small receiver coil offers maximization of the filling factor and a high signal to the noise ratio.
本文介绍了一种双线圈高均匀度磁共振探头的设计与构建，用于测量离频弛豫时间。NMR 离频实验带来了独特的技术问题。长时间的辐照会使样品过热，由于 B(1) 场不均匀性而使自旋去相位，并降低通过要求接收器带宽宽于正常实验所需带宽而接收到的信号。所提出的探头通过引入一个单独的离频辐照线圈来解决这些问题，该线圈比接收器线圈大，并缠绕在杜瓦管上，使其与接收器线圈隔开，从而也从过热中保护样品。辐照线圈的大尺寸也提高了磁场均匀度，因为随着样品直径与磁体（线圈）直径之比的增加，磁场不均匀度也会增加（Blümich 等人，2008）[1]。小的接收器线圈提供了最大的填充因子和高信噪比。
