  Pulse tube refrigerators are becoming more common, because they are cost
efficient and demand less handling than conventional (wet) refrigerators.
However, a downside of a pulse tube system is the vibration level at the
cold-head, which is in most designs several micrometers. We implemented
vibration isolation techniques which significantly reduced vibration levels at
the experiment. These optimizations were necessary for the vibration sensitive
Magnetic Resonance Force Microscopy experiments (MRFM) at milli-kelvin
temperatures for which the cryostat is intended. With these modifications we
show atomic resolution STM on graphite. This is promising for scanning probe
microscopy applications at very low temperatures.
