betsy.weaver@LIGO.ORG - posted 15:33, Thursday 28 May 2015 - last comment - 12:50, Thursday 11 June 2015(18669)
More ETM charge measurements
After a measurement of charge on each ETM yesterday, I took a few more on each today. Attached show the results trended with the measurements taken in April and Jan of this year. There appears to be more charge on the ETMs than in previous measurements, although there is quite a spread in the measurements. The ion pumps at the end stations are valved in.
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Note, the measurement was saturating on ETMy so Kiwamu pointed me to switch the ETMy HI/LOW Voltage mode and BIO state. This made the measurement run with saturation. Attached is a snapshot of the settings I used for the ETMy charge measurement.
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1. I think that the results of charge measurements of ETMY on May, 28 are probably mistaken. I haven't see any correlation in dependence of pitch and yaw from the DC bias. 2. It seems like there was very small response at ETMX LL quadrant at this charge measurements. Other ETMX quadrants are ok. It correlates with results of June, 10 https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=19049
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