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Entry  Mon Apr 14 19:02:09 2014, Jenne, Update, LSC, MICH gets noisy as CARM or DARM offset reduced MICH_fuzzy_when_offsets_small_longerData.pngTRX_TRY_100cts.pngMICH_fuzzy_when_offsets_small.png
    Reply  Tue Apr 15 09:32:19 2014, Gabriele, Update, LSC, MICH gets noisy as CARM or DARM offset reduced 
Message ID: 9809     Entry time: Mon Apr 14 19:02:09 2014     Reply to this: 9813
Author: Jenne 
Type: Update 
Category: LSC 
Subject: MICH gets noisy as CARM or DARM offset reduced 

This afternoon, I was toying around with reducing either the CARM or DARM offsets (so, put in a CARM offset, leave DARM zero, lock the PRMI, then reduce CARM offset to zero.  Or, put in a DARM offset, leaving CARM offset zero, lock the PRMI, then reduce the DARM offset to zero).

When looking at the data, I see that the MICH error signal gets fuzzier when the arms get close to resonance. (Note here that because I forgot to zero the carm offset before finding the resonances, -3 is my zero point for this plot and the next.)

MICH_fuzzy_when_offsets_small_longerData.png

Here is a zoom of the last piece of this time series, but with both TRX and TRY plotted (along with POPDC, CARM_ERR and DARM_ERR), where you can see that I had a momentary power buildup of > 100 transmission counts, which is about 20% of our final expected power.

TRX_TRY_100cts.png

Here is a different time series, showing a reduction of the DARM offset, and you can see that as the offset approaches zero, the MICH error signal gets noticeably more fuzzy.  Somewhere near the 240 second mark, I lose PRMI lock.

MICH_fuzzy_when_offsets_small.png

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