HOWTO hide an STS-2
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An STS-2
with the adjusting pole towards east. The seismometer is placed on a black
gravestone (gabbro) which is part of the shield against air-pressure
variations. |
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The
seismometer is wrapped with cotton wool to prevent air convection and thus
improve the thermal shielding. |
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The upper
part of the air-pressure shield consist of a large cooking-pot which covers
the seismometer. The pot is tightly attached to the gravestone by several
screws. There is a seal between both parts. |
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Again
there is some cotton wool wrapped around. |
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Finally
we use a radiation reflecting rescue sheet to finish the thermal shielding. |
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As the
station is situated within the city we experienced effects from currents
induced in the earth by the public tramway. These currents drive magnetic fields
which interact with the seismometer. To shield the seismometer from this
fields we install a cube of three pairs of Helmholtz-coils. They are driven
by an electronic feedback system with a three-component flux-gate as sensor.
The flux-gate is missing in this picture but may be seen on top of the station
STU seismometer. |
STS-1
seismometers are best protected by a “warp-free plate” and a glass bell which is
partially evacuated.
