  Many modern nanofabrication and imaging techniques require an ultra-quiet
environment to reach optimal resolution. Isolation from ambient vibrations is
often achieved by placing the sensitive instrument atop a massive block that
floats on air springs and is surrounded by acoustic barriers. Because typical
building noise drops off above 120 Hz, it is advantageous to raise the flexural
resonance frequencies of the inertia block and instrument far above 120 Hz.
However, it can be challenging to obtain a high fundamental frequency of the
floating block using a simple rectangular design. Here we design, construct,
and characterize a vibration isolation system with a cylindrical inertia block,
whose lowest resonance frequency of 249 Hz shows good agreement between finite
element analysis simulation and directly measured modes. Our simulations show
that a cylindrical design can achieve higher fundamental resonance frequency
than a rectangular design of the same mass.
