michael.ross@LIGO.ORG - posted 20:51, Tuesday 29 March 2016 - last comment - 10:52, Wednesday 30 March 2016(26326)
BRS-2 Installation DAY 6: COM shifted, new transfer measurements
Krishna, Michael This morning we stopped pumping on the BRS-2 to add a ~0.57 g washer to the top of the balance which shifted the COM up by ~10 microns. We then resumed pumping and remeasured the transfer function using the piezo stacks we installed yesterday. The attached plot shows the results of the measurements along with the model assuming d=0 microns and d=+/-1 microns. Plan for tomorrow: 1. Stop pumping with cart and switch to ion pump 2. Remove piezo stacks 3. Install thermal insulation
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Changing the Section to SEI and tagging SEI in this. Let us take a second to appreciate this entry (and its companion, LHO aLOG 26298) -- The new-and-improved measurement technique is precise enough to measure the "d," (the separation between suspension point and center of mass) to better than a 1 [um] (recall that with BRS1 we were only able to get -35 +/- 5 microns; see e.g. LHO aLOG 13563)! That means we'll get excellent translation rejection from this rotation sensor. Nice work gents!