Renovation of the NW-SE strainmeter
The NW-SE Laser Strainmeter was turned off for renovation work
during the summer of 1995 (the EW strainmeter was kept operating during
this period as backup).
We installed a modern frequency stabalized laser
and replaced pipe-servo units (at the ends of the main
vaccum line) with vacuum bellows; we also
renovated all sections of the main vacuum line to improve the seals.
These modifications to the NW-SE LSM made the instrument much more
reliable and lower maintenance: as with our instrument at Durmid Hill,
the vacuum pumps need to be run only a few days a year to keep the
vacuum at the level needed.
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