arXiv subjects

Claus Schmitzer

Publications and source records attributed to Claus Schmitzer.

3 recordsLinked to original sources

arXiv2025

A double multi-turn injection scheme for generating mixed helium and carbon ion beams at medical synchrotron facilities

The low relative charge-to-mass ratio offset of 0.065% between fully ionized helium-4 and carbon-12 ions enables simultaneous acceleration in hadron therapy synchrotrons. At the same energy per mass, helium ions exhibit a stopping range approximately three times greater than carbon ions. They can therefore be exploited for online range verification downstream of the patient during carbon ion beam irradiation. One possibility for creating this mixed beam is accelerating the two ion species sequentially through the LINAC and subsequently "mixing" them at injection energy in the synchrotron with a double multi-turn injection scheme. This work reports the first successful generation, acceleration, and extraction of a mixed helium and carbon ion beam using this double multi-turn injection scheme, which was achieved at the MedAustron therapy accelerator in Austria. A description of the double multi-turn injection scheme, particle tracking simulations, and details on the implementation at the MedAustron accelerator facility are presented and discussed. Finally, measurements of the mixed beam at delivery in the irradiation room using a radiochromic film and a low-gain avalanche diode (LGAD) detector are presented.

physics.acc-ph↗

arXiv2023

Pulsed RF Knock-Out Extraction: A Potential Enabler for FLASH Hadrontherapy in the Bragg Peak

One challenge on the path to delivering FLASH-compatible beams with a synchrotron is facilitating an accurate dose-control for the required ultra-high dose rates. We propose the use of pulsed RFKO extraction instead of continuous beam delivery as a way to control the dose delivered per Voxel. In a first feasibility test dose rates in pulses of up to 600 Gy/s were observed, while the granularity at which the dose was delivered is expected to be well below 0.5 Gy.

physics.med-ph↗

arXiv2021

Commissioning of low particle flux for proton beams at MedAustron

MedAustron is a synchrotron-based particle therapy centre located in Wiener Neustadt, Austria. It features three irradiation rooms for particle therapy, where proton beams with energies up to 252.7 MeV and carbon ions of up to 402.8 MeV/u are available for cancer treatment. In addition to the treatment rooms, MedAustron features a unique beamline exclusively for non-clinical research (NCR). This research beamline is also commissioned for proton energies up to 800 MeV, while available carbon ion energies correspond to the ones available in the clinical treatment rooms. Based on the requirements for particle therapy, all irradiation rooms offer particle rates of up to 10^9 particles/s for protons and 10^7 particles/s for carbon ions. However, for research purposes, lower particle fluxes are required and were therefore commissioned for the NCR beamline. Three particle flux settings with particle rates ranging from ~2.4x10^3 particles/s to ~5.2x10^6 particles/s were established for seven proton energies below 252.7 MeV. In addition to the particle rate, the spot sizes and beam energies were measured for these settings. Furthermore, three low flux settings for 800 MeV protons with particle rates ranging from ~2x10^3 particles/s to ~1.3x10^6 particles/s were commissioned. Since the commissioned low flux settings are in a regime well below the limits of the available standard beam diagnostics, setting up the beam under these new operational conditions entirely relied on the use of external detectors. Furthermore, a beam position measurement based alignment without using the standard beam profile monitors was performed for 800 MeV protons.

physics.acc-ph↗