Design and characterization of a low-vibration laboratory with cylindrical inertia block geometry

Abstract

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 a higher fundamental resonance frequency than a rectangular design of the same mass.

Performance benchmarking of an ultra-low vibration laboratory to host a commercial millikelvin scanning tunnelling microscope

“…We note the presence of a few resonances in the range of 10-30 Hz on the floating slab (figure 3). Vibration impact within this frequency range [22] is usually attributed to airborne acoustic noise or may be due to pressure fluctuation in the compressed air to the air springs. To uncover the source for such impact, in figure 4(a) we compare vibration spectra measured with the air compressor running and with it switched off.…”