 Thu Dec 10 12:33:04 2015, yutaro, Update, LSC, strange behavior of ASDC 
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I did additional tests for the strange behavior of ASCD. ETMY, ETMX and ITMY were misaligned so that only light reflected by ITMX went into AS port.
I had done similar measurement before with ITMY YAW varied.
Attachment 1 shows how ASDC level changed when ITMX PIT varied. |
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Thu Dec 10 19:53:22 2015, yutaro, Update, LSC, strange behavior of ASDC
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To check if the strange behavior of ASDC is caused by SR2/SR3 or not, I did the following measurement:
ASDC measures the power of the light reflected by ITMX. POXDC measures the power of the light reflected by ITMX and SRM successively. Then I
varied the angle of ITMX in YAW direction and compared the behaviors of ASDC and POXDC. |
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Fri Dec 11 09:35:44 2015, yutaro, Update, LSC, Power recycling gain estimation from arm loss measurement
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I took PR3 AR reflectivity and calculated PRG (PR3 is flipped and so AR surface is inside PRC).
As shown in attached figure, which shows AR specification of the LaserOptik mirror (PR3 is this mirror), AR reflectivity of PR3 is ~0.5 %.
Since resonant light in PRC goes through AR surface of PR3 4 times per round trip, round trip loss due to this is ~2 %. Then I got |
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Fri Dec 11 15:37:50 2015, yutaro, Update, LSC, Power recycling gain estimation from arm loss measurement
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Attached is the plot of relation between the average arm round trip loss and power recycling gain. 2 % loss due to PR3 AR reflection is taken
into account. |
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Fri Dec 11 16:16:36 2015, yutaro, Update, Optical Levers, Calibration of oplevs for ITMX/ETMX
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Based on calibration measurement I have done (elog 11785, 11831), I
updated calibration factors of oplevs on medm screen as follows. Not to change loop gain oplev servo, I also changed oplev servo gain.
C1:SUS-ETMX_OL_PIT_CALIB, C1:SUS-ETMX_OL_PIT_GAIN |
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