attoPUBLICATIONS attoCATALOG-2015/16 | Page 216

Selected Measurements superior position stability 10 5 Displacement (nm) IDS Sensors PAGE 214 Long-term IDS signal stability as demonstrated on a 77 mm long cavity cooled to liquid helium temperature (-269°C) in order to minimize thermal expansion/contraction. 0 −5 − 10 0 10 Time (h) 20 0 2 4 6 Counts (10 ) Proven sub-nanometer signal stability The intrinsic signal stability of the IDS sensor – equivalent to its positional repeatabilty - is unheard of in industrial position sensing. While being specified to achieve a repeatability of 2 nm at 20 mm working distance and 100Hz measurement bandwidth (in vacuum), IDS sensors routinely achieve significantly better performance. The actual measurement above shows positional stability as measured with an IDS3010 on a titanium cavity cooled to liquid helium temperature (-269 °C), temperature stabilized to few milli-degrees. The plot shows position sensing data recorded on a 77 mm long cavity during a 20 hour period of time, measured at 100 Hz bandwidth. The standard deviation of the above shown measurement is 55 picometer!