Reports until 02:28, Tuesday 24 March 2015
H1 ISC (DetChar, ISC)
lisa.barsotti@LIGO.ORG - posted 02:28, Tuesday 24 March 2015 - last comment - 22:19, Tuesday 24 March 2015(17411)
ETMY low noise ESD, MICH feed-forward, ASC cut-offs, low noise coil drivers (started), 28 Mpc 
Evan, Sheila, Dan, Kiwamu, Lisa 

SUMMARY 

The wind dropped below 20 mph in the evening, and we started locking. After some roll, bounce and violin damping, we made it to DC readout @ 8W. We successfully transitioned DARM to ETMY with low noise ESD and got some MICH feed-forward cancellation going. We improved the noise between 30-200 Hz, and reached  28 Mpc  (according to SensMon). 

The noise was more stationary than  previously observed . 

However,  the OMC is still shaking , and it is not good. Dan has a resonant gain for DARM ready to be tested to reduce the noise around 3 Hz, but we didn't manage to get that done tonight. 

We leave the interferometer locked at 28 Mpc starting at March 24, 2015 9:17 UTC . 


DARM control on ETMY with low noise ESD  

We did the transition from ETMX to ETMY L2 for DARM, but the interferometer was very glitchy, and we decided to abandon L2 control and try the new  Den's strategy  to do the feed-forward to ITM(Y) L2. 
Evan got about a factor of 10 subtraction (FM9 has BS plant inversion in LSC-MICHFF filter bank, gain +0.048). 

ASC cut-off filters 

Since none of the ASC loops had cut-offs, we decided to add  some . They are now engaged by the Guardian. A more fine tuning will happen at some point. 

Started switching coil driver to low noise  

We started switching the coil driver to  low noise . Evan will post a table later with the successful switches we did after acquiring the DRMI lock. We need to do more work on this, some failed.
Comments related to this report
evan.hall@LIGO.ORG - 02:35, Tuesday 24 March 2015 (17412)
Link

Spectra attached.

Images attached to this comment
daniel.hoak@LIGO.ORG - 02:38, Tuesday 24 March 2015 (17413)
Link

Here is a plot of the lingering coherences with LSC DOFs.

Images attached to this comment
gabriela.gonzalez@LIGO.ORG - 05:15, Tuesday 24 March 2015 (17414)
Link 

Very nice progress!
albert.lazzarini@LIGO.ORG - 05:53, Tuesday 24 March 2015 (17415)
Link 

Excellent news. Great progress.
thomas.massinger@LIGO.ORG - 09:48, Tuesday 24 March 2015 (17420)DetChar
Link

This is fantastic progress, congratulations!

For anyone that would like to look at the data quality or run any DetChar tools on this data, the following GPS times can be used:

1111223896 - 1111239923

Duration: 16027 seconds

nergis.mavalvala@LIGO.ORG - 11:52, Tuesday 24 March 2015 (17426)
Link 

This entry should make Lisa a contender for her "best log entry" prize. Nice going, everyone!
evan.hall@LIGO.ORG - 22:19, Tuesday 24 March 2015 (17449)
Link

These are the coil driver states that we've been using so far:

OLD PRM PR2 SRM SR2 PR3 SR3 BS
M1   1 1 1 1 1 1
M2   2 2 2 1 1 1
M3 2 2 2 1 1 2 —

 

OLD IX IY EX EY
R0 1 1 1 1
M0 1 1 1 1
L1 3 3 2 2
L2 2 1 1 1

Now we've managed to switch to the following configuration for acquisition (following the tables in LLO#16565):

ACQ PRM PR2 SRM SR2 PR3 SR3 BS
M1 2 2 1 2 2 2 1
M2 2 3 2 3 3 3 2
M3 2 2 2 2 2 2 —

 

ACQ IX IY EX EY
R0 1 2 1 1
M0 1 2 1 1
L1 3 4 2 2
L2 2 1 1 1
 

Green indicates a low-noise state, and red any other state. So far we have encountered the following things:

  • If any stage of the SRM is switched to a low-noise state, it will start to saturate. We are trying to figure out whether this is a problem with the LSC (which feeds back to M2 and M3) or the ASC (which feeds back to M1).
  • ITMX M0 appears to be miswired; changing the state request appears to affect the test/coil bits instead, resulting in an error. Jeff and Richard are looking into this.