J. Kissel

Standard health checks on HAM5 suspensions today (SRM, SR3, OFI, and ZM2) as we prepare to close out HAM5. All suspensions pass their tests.

/ligo/svncommon/SusSVN/sus/trunk/HLTS/H1/SR3/Common/Data/2018-05-02_H1SUSSR3_All_OSEM_ASDs.xml
/ligo/svncommon/SusSVN/sus/trunk/HSTS/H1/SRM/Common/Data/2018-05-02_H1SUSSRM_All_OSEM_ASDs.xml
/ligo/svncommon/SusSVN/sus/trunk/OFIS/H1/OFI/SAGM1/Data/2018-05-03_2004_H1SUSOFI_OSEM_ASDs.xml
/ligo/svncommon/SusSVN/sus/trunk/HTTS/H1/ZM2/SAGM1/Data/2018-05-03_H1SUSZM2_OSEM_Noise_ASDs.xml

/ligo/svncommon/SusSVN/sus/trunk/HLTS/H1/SR3/SAGM1/Data/
    2018-05-03_1851_H1SUSSR3_M1_WhiteNoise_L_0p02to50Hz.xml
    2018-05-03_1851_H1SUSSR3_M1_WhiteNoise_P_0p02to50Hz.xml
    2018-05-03_1851_H1SUSSR3_M1_WhiteNoise_R_0p02to50Hz.xml
    2018-05-03_1851_H1SUSSR3_M1_WhiteNoise_T_0p02to50Hz.xml
    2018-05-03_1851_H1SUSSR3_M1_WhiteNoise_V_0p02to50Hz.xml
    2018-05-03_1851_H1SUSSR3_M1_WhiteNoise_Y_0p02to50Hz.xml

/ligo/svncommon/SusSVN/sus/trunk/HSTS/H1/SRM/SAGM1/Data/
    2018-05-03_1845_H1SUSSRM_M1_WhiteNoise_L_0p02to50Hz.xml
    2018-05-03_1845_H1SUSSRM_M1_WhiteNoise_P_0p02to50Hz.xml
    2018-05-03_1845_H1SUSSRM_M1_WhiteNoise_R_0p02to50Hz.xml
    2018-05-03_1845_H1SUSSRM_M1_WhiteNoise_T_0p02to50Hz.xml
    2018-05-03_1845_H1SUSSRM_M1_WhiteNoise_V_0p02to50Hz.xml
    2018-05-03_1845_H1SUSSRM_M1_WhiteNoise_Y_0p02to50Hz.xml

/ligo/svncommon/SusSVN/sus/trunk/OFIS/H1/OFI/SAGM1/Data/
    2018-05-03_1830_H1SUSOFI_M1_WhiteNoise_L_0p02to50Hz.xml
    2018-05-03_1830_H1SUSOFI_M1_WhiteNoise_T_0p02to50Hz.xml
    2018-05-03_1830_H1SUSOFI_M1_WhiteNoise_Y_0p02to50Hz.xml

/ligo/svncommon/SusSVN/sus/trunk/HTTS/H1/ZM2/SAGM1/Data/
    2018-05-03_1827_H1SUSZM2_M1_WhiteNoise_L_0p02to50Hz.xml
    2018-05-03_1827_H1SUSZM2_M1_WhiteNoise_P_0p02to50Hz.xml
    2018-05-03_1827_H1SUSZM2_M1_WhiteNoise_Y_0p02to50Hz.xml

Minor detail:
While taking spectra of the SR3 AOSEMs, I noticed they had obviously, artificially low, high-frequency noise. Digging around, I found that the SR3 M3 OSEMINF banks for each of the four OSEMs had an additional filter called "But60" (besides the standard 10:0.4 that inverts the SatAmp whitening, and the "to_um" scalar gain filter that converts ADC counts to [um]). This filter is a 60 Hz Butterworth low-pass filter, and after brainstorming with Jenne, we agreed that this filter is in place because SR3 has a "cage servo" in which the M3 OSEMs are fed back to to the M1 top mass actuators to keep the position of SR3 optic fixed to the SR3 cage (implemented before O1, see LHO aLOG 20571). It's an EPICs servo, word on the street (i.e. comments in the SR3_CAGE_SERVO guardian code) is that its bandwidth is 100 * 1/(3*60) = 0.555 Hz.

Maybe the filter was installed after a satellite amp went rogue (see LHO aLOG 25500). 

Whichever, doesn't matter. I just want to get keywords of this filter in the aLOG such that, in two years, when we've found a magical scheme to control the angle of the SRC and/or we've found that the venetian blinds (D1700239, installed Dec 2017, LHO aLOG 39663) fix the alignment drift at the source, then we remember why we have this filter in place and turn it off.