camilla.compton@LIGO.ORG - posted 16:42, Monday 28 March 2022 - last comment - 08:50, Tuesday 29 March 2022(62385)
ETMX Ring Heater on tonight 8pm to 2amPT. Plate Removed.
After alog 62338, repeating a 6 hour ring heater test for 2W tonight 8pm to 2am PST for ETMX. This morning I removed the Hartmann plate from the ETMX CCD so we expect to get some insight into what bad alignment is causing our beam shape to change with the ETM being heated. Camera settings adjusted from 1Hz to 20Hz (48400usec exp).
Attached are the CCD photos at HWS EX when ETMX is cold (0.44W) and hot (RH=2W). The changing total pixel value is is clearly due to the beam shape changing. But we do not expect the beam shape to change visibly with ETM heating. There must be significant clipping somewhere to cause this.