Today I repeated a few damping loop injections that we had done at LLO. I did all 6 BOSEMs on the BS and 3 on ITMX. I injected circa 100 above ambient. I did not see anything for the BS injections, and saw a small coupling on the ITMX. It remains to be seen if the other suspensions slowly add up to a significant contribution to DARM. Sheila recommended that Josh, the new fellow, take this on in consultation with Jeff so we sat down and I passed on the methods.
The dtt's are to be found in: /ligo/home/anamaria.effler/dtt/damping/ and each test is saved separately. The first attachment shows an example injection on the BS, with the references being the background. The second attachment shows the injection awggui. I did a uniform noise with an 8th order butterworth bandpass 10 to 100 Hz. The gain was 600 for all BOSEMs tested, BS and ITMX. For DARM projection it's best to inject directly at the OSEM basis such that the noises are easy to add up incoherently.
I copied over a coupling calculation code to be found in: /ligo/home/anamaria.effler/scripts/
The three python files there, as well as the darmcalGDS_meters.txt should be copied to be used. The coupling_utils.py is kinda all that's needed, but an example usage is in test_coupling_utils.py. In this script, at the bottom, one can choose the channel injected, add the times for the background and injection, duration and the frequency range to be used, filename to save the data, etc. It will show and save a plot of the derived estimated ambient contribution to DARM from that injection. See example plot for ITMX F2 in the third attachment. It also saves a text file of the coupling function to be used for noise budgets, but only of the measured blue points (which are determined by the darm threshold chosen - for this data I chose 2). I set the default DARM to be GDS CLEAN but it can be changed in the call of the coupling function or in the base code.
