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.

Back to PFO home page