aLIGO LHO Logbook

H1 SUS

kiwamu.izumi@LIGO.ORG - posted 01:39, Wednesday 22 January 2014 - last comment - 08:56, Wednesday 22 January 2014(9419)

Coil balance of M2 and M3 on PRM

I did the coil gain balancing on the M2 and M3 stages of PRM. Here are the results:

%% M2 stage

H1:SUS-PRM_M2_COILOUTF_UL_GAIN -0.961 H1:SUS-PRM_M2_COILOUTF_LL_GAIN 1.012 H1:SUS-PRM_M2_COILOUTF_UR_GAIN 0.987 H1:SUS-PRM_M2_COILOUTF_LR_GAIN -1.039

%% M3 stage

H1:SUS-PRM_M3_COILOUTF_UL_GAIN -0.999 H1:SUS-PRM_M3_COILOUTF_LL_GAIN 0.985 H1:SUS-PRM_M3_COILOUTF_UR_GAIN 1.015 H1:SUS-PRM_M3_COILOUTF_LR_GAIN -1.001

I used the same technique as Keita did for BS (see alog 9080), although WFS_REFL_B_LF was used in stead of an oplev because PRM doesn't have its own oplev.. In addition to it, because the WFS signals are not connected to the suspension LOCKINs, I simply used diaggui to check the amplitude of the excitation line. The excitation was introduced by the LOCKIN OSC with an amplitude of 500000 and 200000 counts for the M3 and M2 stages respectively. The frequency was at 4.1 Hz for both cases.

Comments related to this report

jeffrey.kissel@LIGO.ORG - 08:56, Wednesday 22 January 2014 (9425)

Link

I've captured and committed a new safe.snap for h1susprm, such that these values remain for all time. 
(Note, I'd paused the excitation that is on-going with PRM to turn off all LOCK filters, alignment offsets, and master switch as per the standard configuration, but things were only off for a few minutes during one, many minute, average of the TF so it should not affect the results significantly.)