LIGO Document P1000071-v1
- One of the major research goal for the third generation of
gravitational waves interferometer detectors is the reduction of the
noise at low frequency, which is dominated by the seismic noise. The
seismic isolation system projected for these detectors is a
fundamental problem in their building to improve their low frequency
band sensitivity. The most helpful and adopted seismic isolation
system is based on the GAS ( Geometric Anti Spring ) filter, which,
together with the EMAS ( Electro Magnetic Anti Spring ) mechanism,
allows the exploration of resonant frequencies below 100 mHz. Although
not all the world detectors make use of these filters ( Virgo make use
of a different prototype, the so called “Super Attenuator” ), each
isolation system is based on Maraging steel blades, a precipitation
hardened alloy that allows the production of creep free blade
springs. At high frequencies ( >1 𝐻𝑧), they show high attenuation
performance, while at low frequencies anomalies have been observed. A
previous work, investigating on the dissipation properties of these
blades, revealed that the dissipation properties to them connected are
due to the dislocations, linear impurities, present inside their
material structure. Starting from this viewpoint, the most promising
idea to improve the attenuation performance, is the exploration of
different materials which don’t contain dislocations, such as LM001
Zr based bulk metallic glass ( LM001 ), a monolithic bulk
metallic glass ( BMG ) composed by Zr ( 41,2 %), Ti ( 13,8%), Cu
( 12.5% ), Ni ( 10% ) and Be ( 22,5% ). This thesis work is a
comparative study between this two materials to explore the
possibility to substitute the Maraging blades still adopted with
possible future LM001 blades.
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