Selected Applications
FPS Sensors
Measuring Brownian Motion of Commercial Micro-Cantilevers
The resolution capability of the IDS was demonstrated by measuring the Brownian motion of micro cantilevers . Measuring the tiny vibrations of objects excited only by its thermal energy is typically challenging the resolution capabilities of a measurement system . The cantilever was placed on attocube positioners and measured with the focusing sensor head ( D12 / F2.8 ). This sensor head has a shot diameter of smaller 2 μm . The figure clearly shows an individual resonance peak at 165.6 kHz excited due to Brownian motion .
( attocube application note SEN15 , 2016 )
The shown plot depicts the fast Fourier transform ( FFT ) analysis between 100 and 400 kHz of a commercial cantilever . The cantilever under investigation has the following dimensions : 225 μm x 38 μm x 7 μm ( L x W x T ). The resonant frequencies of this cantilever can be seen at 165.6 kHz and the noise floor in the presented frequency range is around 2 pmRMS / sqrt ( Hz ).
The figure shows the measured positions while the sampling rate of the encoder positions was set to 1 kHz . The position drift observed over the full period of 34 days and a cumulated dose of 3 MGy was only 150 nm with the coated sensor head and 400 nm with the uncoated one .
Radiation Harsh Environments
The FPS3010 can operate under extreme radiation opening ways to use interferometric systems and subsystems close to synchrotron beams and beamlines , or other environments with high radiation . An experiement conducted under irradiation from a 60Co source ( 1.17 MeV / 1.33 MeV γ- and 0.31 MeV β-rays ) shows the stability concerning radiation harsh environments of attocube ’ s sensor heads . The FPS3010 controller was placed outside the chamber and located in a temperature controlled chamber located in a nonradioactive zone . The temperature stability inside the chamber was better than 1 ° C during the complete measurement cycle . The total cumulated dose at the end of the measurement was 3.024 MGy in water equivalent . The setup and installation were proven to be robust in terms of mechanical vibration , giving a position uncertainty of less than 10 nm over a measurement period of 34 days . The measured positions were stable within a few 100nm during the whole time .
( attocube application note SEN10 , 2014 )