We would like to move several of the calibration line frequencies, in order to get them out of our most sensitive region, as well as to help give more accurate measurements of the interferometer properties. 

There are enough constraints on what frequencies are okay to use for calibration lines that I made a little script to help visualize where we're proposing to put the calibration lines at the lower (below 20 Hz) frequencies.  Lilli has a nice summary of these constraints in alog 44590.  EvanG provides in alog 44892 the frequency regions that are okay from the viewpoint of puslar searches.  

Currently, our calibration line frequencies are [15.1 Hz, 16.7 Hz, 35.9 Hz, 36.7 Hz, and 331.9 Hz], and I am proposing to change those to [15.6 Hz, 16.4 Hz, 17.1 Hz, 17.6 Hz, and 410.3 Hz].  (We also have lines at 7.93 Hz and 1083.7 Hz, but we're not moving them).

In the top panel of the attached figure, I have horizontal bars for the okay ("non-vetoed") regions according to the pulsar group, assuming we need to be at least 0.1 Hz away from known pulsars for which we could potentially measure spindown limits.  I show the LLO calibration frequencies in blue (since we don't want to use the same frequencies, although we have been for the 15.1 Hz line since about January 14th); several frequencies in yellow that have been proposed in various alogs, including those from Lilli and Evan linked above; the beam splitter rigid body frequency (Lilli's alog quotes 17.54 Hz for this, but it looks like it's closer to 17.8 Hz for us); and the ADS frequencies that we are currently using, since we must not drown them out with calibration lines.  Finally, in red, I show my new proposed suspension calibration frequencies: 15.6 Hz, 16.4 Hz, 17.1 Hz, and 17.6 Hz. 

In the bottom panel, I show where these frequencies lie in relation to our DARM spectrum at a time that the calibration lines were off (so that it's clear that current cal lines at, for example, 16.7 Hz, would change and not interfere with these new frequencies). 

In the bottom inset, I also show the proposed frequency for the pcal line that is used to measure the DARM cavity pole.  LLO uses 434.9 Hz for this line.  We will use something lower, since our DARM cavity pole is currently much lower than L1's. 

Either tomorrow or Wednesday, Jeff and I will:

• Change our calibration lines to the new frequencies.
• Change the DARM2 FM4 notch from a 331 Hz bandstop to a 410 Hz bandstop.
• Change the matching filter module in the CAL-CS copy of DARM2.
• Change (check) the list of filters in the H1 modelparams file.
• Change / check the calibration line frequencies in the pyDARM models / modelparams files.
• Create new EPICS records for  time-dependent value calculations.
• Tell Maddie, so that she can update the GDS pipeline.