Surface preparation chamber for beta-NMR

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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.