Barrier voltages could be detrimental to beam commissioning

The formal scheme is that we trigger the Vac and Vbb voltage with a relative delay to the referential signal.

However, as the by the default idea of pulse density control (with or without threshold for accumulated required voltage), in the phase space of  (t, dp_p), the bunch would travel to the negative part of dp_p, then go to the right-hand-side, where the beam tail would meet the Vbb there. Thus we can observe that the bunch is kicked back from there.

In a better situation(or ideal case), the Vbb should do its own job by just restrain the bunch from becoming longer due to momentum deviation and longitudinal space charge.

Thus, when we set the Vac and Vbb, we should use a different referential signal( or with modified delays), to ensure that Vbbs are located at the equal distance from the center every turn.

Let Vbb does its job. The same thing should be applied to Vac.