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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).
Radiation Harsh Environments
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.
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 positio