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Description
MedAustron is a synchrotron based medical accelerator using protons and carbon ions for cancer treatment, it is based near Vienna in Wiener-Neustadt, Austria. It has been operational since 2016 and it treated 193 patients in 2018.
Simultaneous beam intensity and beam profile measurements over time with various beam parameters at the IR1 non-clinical research beamline have been performed with Medipix3, a single quantum counting hybrid pixel detector typically used for x-ray and electron detection.
The energy range used in these measurements for protons is 62 to 800 MeV and for carbon ions is 120 to 400 MeV/A, which is the full clinical range with the addition of the experimental 800 MeV proton option intended for various research applications including proton CT.
Count rate linearity was investigated using degrader plates to vary between approximately 10 and 100% of the beam intensity, resulting in count rates of up to 10$^9$ particles per second over the whole sensitive area of 28 x 28 mm$^2$.
In addition, experimental low flux proton beams have been measured reducing the intensity over intermediate steps down to 10$^3$ particles per second. With and without the measurements using degrader discs, current analysis shows very high linearity (R$^2$ = 0.9995) between the expected proton fluence at 62 MeV and the integrated counts on the Medipix3 from 10$^7$ to 10$^{11}$ total counts. Average deviations of the measurements from the linear fit were found to be 2.9% without the degrader measurements and 36.2% with them.
Another set of linearity measurements were performed using 800 MeV protons and degrader discs, they show high linearity (R$^2$ = 0.9749) between the integrated counts over the whole detector and the degrader percentage, excluding the degrader 10 measurements.
Frequency components in the intensity of the beam have been calculated for proton beams at 50 to 1000 FPS (frames per second), significant components at 252.51 Hz (σ = 0.83), 49.98 (σ = 0.29) and 30.55 (σ = 0.55) were observed.
