J. Warner, K. Venkateswara

Jim installed Rich's SC filters to all sensor correction filter banks. This afternoon, I turned on ETMX SC to Stage 1 using the tilt-subtracted ground sensor and then for ITMX using the normal ground sensor (STS) along X. For Z, SC to HEPI was enabled for both chambers. Sheila then aligned the arms and locked them using ALS.

The aim was to observe if SC reduced arm motion between~ 50 to 500 mHz as indicated by the local sensors while keeping the low frequency motion small. The noise in this band seemed lower, but unfortunately activity at ITMX increased ground motion as measured by the seismometers which ended up re-injecting excessive noise at low frequencies. This test should be repeated later in the evening or night when activity at the corner is reduced.

For the moment, I have left tilt-subtracted SC on at ETMX and SC off at ITMX.