Jess, Andy, TJ, Duncan, Detchar, 

In entry 18783 (at 19 UTC on June 2) Jeff et al performed an autocal on the SUS DACs for the Modecleaner, in response to the report in log 18739. He asked Detchar to report if the glitches are gone, if they come back over time, etc. 

What we've found so far is that the DAC glitches are still present on MC2 M3 zero crossings. Their amplitude (seen in LSC MCL and IMC alignment channels) has reduced by a factor of 2. And their amplitude does not appear to be increasing over time since the restart, on the timescale of days. 

Figure 1 shows normalized spectrograms of the DAC glitches witnessed by LSC MCL before and after the Autocal. 

Figure 2 shows a time vs SNR plot of the individual glitches (only during observation intent time) in LSC MCL (at frequency < 200Hz to be dominated by DAC glitches). The many glitches with signal-to-noise ratio of 30 are now many glitches with SNR 15-20. Autocal occurs at hour 19. 

Figure 3 shows the same plot for IMC-DOF_1_P_IN1_DQ, another good witness of these glitches. 

Figure 4 caption: The Glitchgrams on the bottom show glitchiness of IFO, not related to the MC2 DAC glitches (we think) but just to see when IFO is locked and in good state. The top plots are all normalized spectrograms. The left two plots are before autocal, MCL glitches are really loud. The right five plots are after autocal, most glitches are less loud. Where "loud" is assessed by top of color bar (admittedly poor measure).

Figure 5: Same for two IMC alignement channels DOF 1 P and DOF 2 Y that are both good witnesses of DAC glitches. 

Jess wrote nice scripts to make the glitch vs time plots so we will keep an eye on these to see when/if the amplitude increases. 

Notes: Sorry Jeff, Peter, et al, I realize now that amplitude rather than SNR, calibrated units, and the SUS VOLTMON channels would be more useful for assessing the size of the DAC glitches. We'll work on that.