Surface preparation chamber for beta-NMR

我们位于温哥华TRIUMF的新型深度分辨β -核磁共振（β - nmr）设施的一个独特之处在于，8Li探针束是在低能量下产生的，因此可以减速，使探针在2到100纳米的平均停止深度植入。在从界面或自由表面的这个深度范围内，我们可以解决许多以前不可能解决的有趣问题（包括基础问题和应用问题）。因此，表面和近表面区域的清洁度和质量对该计划的成功至关重要。在此，我们申请资金购买超高真空（UHV）兼容的样品制备系统，该系统将作为我们现有的UHV β -核磁共振光谱仪的前房。这将使我们能够溅射清洁和退火样品，以产生高质量的表面。制备的样品随后可以转移到特高压低温恒温器，而不暴露在空气中。目前这是不可能的，因此任何空气敏感表面都必须用适当的金属覆盖，严重限制了可以解决的自由表面现象的范围。

A unique feature of our new depth-resolved beta-nuclear magnetic resonance (beta-NMR) facility located at TRIUMF in Vancouver is that the 8Li probe beam is that it is produced at low energies, and can thus be decelerated such that the probes are implanted at average stopping depths of 2 to 100 nm. Within this depth range from an interface or free surface, there are many fascinating questions (both fundamental and applied) that we can address that were previously not possible. Hence, the cleanliness and quality of the surface and near surface regions is critical to the success of this program. Here, we request funds to purchase a Ultra High Vacuum (UHV)-compatible sample preparation system that will act as an antechamber to our existing UHV beta-NMR spectrometer. This will enable us to sputter clean and anneal samples to yield high quality surfaces. The prepared sample can subsequently be transferred into the UHV cryostat without being exposed to air. Currently this is not possible, so that any air sensitive surfaces must be capped with an appropriate metal, seriously limiting the range of free surface phenomena that can be addressed.