Just posting data that Fabrice had requested for a talk. The setup: I wanted to measure the performance of sensor correction on ETMX. I turned off the feed forward (which I've seen add some noise at .5hz, not much, but I've been meaning to investigate) and got .001 bw measurments with the sensor correction on and off. The ISI was fully isolated, with 45mhz blends in Y and 90mhz blends in X. On the first 3 spectra (X,Y &Z) black (ground),orange(st1 t240's) and red(st2 gs13's) are sensor correction on, brown (ground), blue (st1 t240's) and grey (st2 gs13's) are sensor correction off. In X&Y, we are using Ryan's .5hz notch sensor correction on the ISI and in Z we are using RichM's broadband low frequency sensor correction on hepi (fourth & fifth plots).