This is to report some findings during operation that should be looked into (mostly to avoid in the future, because both negatively affect data quality of the user expt at FXE):
- At the moment, the 99:1 mode affects 4 to 5 pulses out of 100 in SA1, see first screenshot that shows in the top right the IPM reading with each blue point denoting the average pulse energy in a train. This was not always the case. After initial setup on thursday it did affect only a single train out of 100.
- On 27.10., the switching of SA2 between 1 and multiple bunches affected SA1 beam heavily, see the jumps in SA1 pulse energy in the second screenshot shown here:
- The pulse energy dropped by 15% and
- the pointing changed vertically by 150 um on the FXE PI (data not shown, but available from karabo trendlines)
Edit 8.11.: Added screenshot (grafana/ctrend) to show that the vertical displacement was permanent (not corrected by the feedback) |