Ponente
Descripción
Recent advances in hadrontherapy and radiobiology require precise information on the particle beam properties. For in-beam detection of protons and ions a low areal density is mandatory to allow for passage of the primary particles at negligible energy loss and scatter. We report on two developments from i3M.
Prompt-gamma imaging and spectroscopy (PGI, PGS) can be applied for range verification in real-time to increase the precision of hadrontherapy. Gamma photons of several MeV are detected using scintillator crystals with large volumes. A beam monitor made of scintillating fibers coupled to fast photomultipliers has been used to suppress background events through a time coincidence with the incoming protons and ions. It has been tested at a therapy facility with clinical beam intensities up to $8 \times 10^7$ $p$/s [1,2]. We have recently built a multi-channel version with individual readout of single fibers for improved spatial resolution. First data have been obtained at the external beamline of the 18 MeV cyclotron at Centro Nacional de Aceleradores (CNA).
Pulsed ion beams with much higher intensities are generated in laser-plasma interactions. For the measurement of the proton fluence in bunches of <1 µs duration we have built a transmission monitor based on an ultra-thin scintillator sheet which allows for passage of protons of a few MeV. Its response to pulses reaching $5 \times 10^5$ $p$/100 ns has been calibrated at the CNA tandem accelerator. This device may be applied for real-time dose control in the ultra-high dose rate regime.
Financed by Generalitat Valenciana through the program “I+D+i Subvenciones para Grupos de investigación consolidados” (AICO), ref. CIAICO/2022/008.
[1] P. Magalhaes Martins et al., Frontiers in Physics 8, 169 (2020)
[2] R. Dal Bello et al., Phys. Med. Biol. 65, 095010 (2020)
