Procedure

The procedures for the microscopes are generally similar, but have specific differences. The STM tip is changed by snipping off a piece of Platinum-Iridium wire from a larger piece and placing it in the tip holder. This sends an electrical current, creating an image when approached. The AFM uses pre-made tips that are inserted into a cradle on the bottom of the scan head. This cradle is approached and scans using a laser that measure the distance of the head. The user interfaces on the computer are very similar, with some functions specific to each microscope.

The procedure for making samples is the same for each type of scope. Becky usually prepares a sample ahead of time by placing an annealed piece of Au(III) on a Polonium-210 sample. I am unable to do this as I am not licensed to use or interact with the radiation itself. The Polonium gives off alpha particle radiation, which impacts of the surface. These impacts are what we search for in our scans. -Anealling is a process used to flatten the surface of the gold even more. Our method consists of passing a hydrogen torch over the sample quickly at five second intervals for five minutes. -At first, the samples would be exposed to the Polonium-210 for several hours or overnight. Gradually, the length of the exposure was increased. Lately, the time exposed has been increased to roughly a week, with the sample being exposed from a Tuesday afternoon to the following Monday. The idea behind this is that the longer the sample is exposed, the higher the chance it is hit by particles. -The sample is placed on a disk over the Polonium-210 in a nitrogen purge, with nitrogen gas constantly flowing over the sample, preventing foreign materials from settling.