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Message ID: 2154     Entry time: Mon Mar 26 16:54:29 2018
Author: Craig 
Type: DailyProgress 
Category: North Cavity 
Subject: NCAV likes to switch to TEM10 mode 

A couple of observations from the lab today:

1) The TRANS and REFL for both cavities are a lot more stable ever since we landed the table, but still are not completely stationary on the order of 30 minutes.  They are now correlated, meaning that as TRANS goes up, REFL also goes up, meaning these changes are most likely due to the EAOM temperature fluctuations.  These fluctuations are much less than the alignment drifts we were having from the air springs, and slightly less than from the floating table wobbling around.  Need to turn on the ISS.

2) North cavity sometimes glitches and jumps from the TEM00 to the TEM10 mode. Pics because it did happen.  Turning on the autolocker helps here since the TEM01 mode doesn't have a high enough threshold TRANS voltage, so it unlocks the cavity and tries to find the TEM00 mode again.  Unclear why the NCAV would make a massive jump in frequency like this in the first place, could result from a PZT glitch.

Attachment 1: NorthCavityLockedtoTEM10Mode.jpg  1.795 MB  Uploaded Mon Mar 26 18:01:01 2018  | Hide | Hide all
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