Josh Smith, TJ Massinger, Andy Lundgren, Laura Nuttall
We've taken a look at the ~8h lock stretch on 15th May where the intent bit was active. We've specifically looked for evidence of DAC (for example 17555) and whistle (17452) glitches which have been present in the past. We find no sign of whistles glitches correlated with IMC-F (could be other sources but we haven't seen any yet) and we also find no evidence of DAC glitches.
The glitch rate for this lock is some of the best we have seen for aLIGO (at either site). Attached is the glitch rate plot for the 15th, which shows the glitch rate to slowly decrease throughout the lock. We'll continue to investigate this lock.
I've taken a look at the data from a number of lock stretches (when the intent bit was not active) since the 10th April (to 17th May) when Daniel/Sheila powered off the fixed frequency source being used for ALS (17825). Since this work was completed I cannot find any evidence of whistle glitches. I've specifically looked for whistle glitches correlated with IMC-F (which was the indication in the past). We will keep an eye on future lock stretches to see if they come back, but for now the problem seems to have been solved!