jeffrey.kissel@LIGO.ORG - posted 17:41, Friday 03 November 2017 - last comment - 14:23, Wednesday 15 November 2017(39288)
HAM4 Baffle and HWS Components B&K Hammered
J. Kissel Since HAM4's construction / installation stuff for this vent is complete as of yesterday's HWS Scraper Baffle install (LHO aLOG 39266), and the debugging of SR2's M2 OSEM today (LHO aLOG 39277), I took the afternoon to start B&K hammering all of the new / old baffle equipment and HWS mirror / lens mounts. Note, I deliberately skipped the SR2 cage, since nothing has changed on it since it was originally measured in LHO aLOG 12089, and I trust that Betsy and Travis successfully re-dogged and torqued bolts when they finished the relocation a few days ago LHO aLOG 39240. Will post pictures and results next week.
I'm attaching some plots of Jeff's data. Would be nice if the B&K data were easier to get into a publishable form, I can't guarantee I haven't screwed something up in here, a lot of places where it would be easy to make a mistake. Some of the TFs have almost no coherence, Jeff said it was hard to get the accelerometer close in couple cases.
One extended point about getting data from the B&K machine. It's possible to export one data set at a time (i.e. get the tf & coherence for one channel). Then to get them in a manageable format for matlab, I used sed to remove the last seven lines and the first 84 lines from the exported data txt file. This was some thing of the form:
sed -i '6486,6492d' *100-1100*.txt
to remove the last seven lines of all of Jeff's data files that had 100-1100 in the name (for the frequency band) and:
sed -i '1,84d' *.txt
to remove the first 84 lines from all of the files in the directory. Best to backup your data before doing this, cause sed won't ask if you're sure. I had to try several times to get it right. The '1,84d' tells sed to delete lines 1-84. There's probably some clever way to tell sed to remove the last seven lines, I couldn't find it, so I just looked in the file to see how many lines there were.