After ion source cleaning, this 5977B (inert extractor source) is no longer hitting relative abundance targets during DFTPP target tuning. Should be hitting about 55% for mass 219, but only giving 40-45%. While other ramps seem normal to me, ion focus lens gives the following ramp:
At this point, I have tried replacing all insulators, as well as replacing the entire source (we keep enough new spare parts to assemble an entire unit). No change, ramp still looks odd and tuning is still unable to hit targets.
I tried running a calibration, had trouble with low response factors with some compounds at the low end of my curve - namely benzo[a]pyrene and a couple of phthalates. I actually wonder if these low responses may be unrelated to the tuning issue, but I would appreciate another perspective on it.