Since we have ions in the ring now, we looked at the PMT thresholds and the widths. In order to do so we looked at the Raw Signal directly before the CFD and its output simultaneously. You can now set the threshold just above the noise. If the threshold is too low you will also see flat lines in the oscilloscope when triggered on the CFD output. New values:

PMT Mitte
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Width: 200 -> 220 (60ns -> 90ns)
Threshold: 20 -> 5

PMT Nord
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Width: 200 -> 220 (60ns -> 90ns)
Threshold: 12 -> 10

PMT Süd
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blind.