Quality assurance of scanned proton beams at different gantry angles using an ionization chamber array in a rotational phantom

•Development non gantry mounted ‘set-and-forget’ QA procedure for 9 beam parameters.•Freedom to measure at all gantry angles.•The sensitivity is comparable to the scintillator detector.•Measurement time is reduced by 40%.•QA results over 12 months at our pencil beam scanning proton centre.