Taking+before+and+after+images

__ The difficulty of taking before and after images with the STM __ This is what has presented the most difficulty in my project. In STM a major problem during the creation of the STM was thermal drift. With the creation of the scanning electron microscope in ultra high vacuum, thermal drift has greatly been reduced by the ability to run tests at very low temperatures (as low as 4.2K when the inner chamber is filled with liquid helium). The original creators of the STM, [|Rohrer and Binnig] encountered these problems with thermal drift in their early years of testing. The major difficulty for this test I am running is that shooting the sample with the laser actually creates thermal drift and disrupts the equilibrium of the gold sample with the surrounding space inside the scope. Assuming the conditions are ideal and there is no thermal drift before the laser is shot; when I shoot the laser I heat up the sample and create a substantial amount of drift. Most of the time I am unable to find the area of the gold that I previously shot with the laser because it has drifted away from this location.

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