daniel.sigg@LIGO.ORG - posted 15:54, Friday 02 February 2018 - last comment - 11:01, Saturday 03 February 2018(40394)
ALS laser End X
We shifted the ALS laser in the X end stations by ~18.6GHz (-6.2V on the crystal temperature control voltage) to bring it close to the PSL. This offset was then relieved using the front panel potentiometer. The ALS autolocker is working again.
The same shift will have to be applied to the Y end laser.
Some other strangeness:
- The VCO RF output monitor (H1:ALS-X_VCO_OUTPUTMON) reads -4.8dBm when it should read +19dBm. We verified that the VCO still outputs 19dBm, so this seems a problem of the RF power readback.
- One LO readback channel of the WFS reads -11 instead of ~18dBm (H1:ALS-X_WFS_A_DEMOD_LOMONCHANNEL_4).
The beat note had 8MHz sidebands (attached). Shouldn't be a big problem but I don't remember seeing this before.