In contrast to PMT Mid, the difference between ions and no ions in the ESR (see screenshot scaler) is not visible. Signal gets higher with injection and shows some kind of exponential decay afterwards. 
Beam was dumped at 500 and 1200s. Even after the dump, the signal steadily drops.
We tried to adjust the threshold such that a difference between ions in the ring and not becomes visible, but even with a minimal threshold no effect was visible.