Energy measurement of clinical proton beams with a telescope of Ultra-Fast Silicon Detectors

Within the MoveIT-project of the National Institute for Nuclear Physics (INFN), the University of Torino (UNITO) and INFN-Torino are developing a detector made of a telescope of two Ultra-Fast Silicon Detectors (UFSD) aligned along the beam direction to determine the energy of clinical proton beams from the measurement of the time-of-flight of single protons. Following the promising results obtained at the Centro Nazionale di Adroterapia Oncologica (CNAO, Pavia, Italy) with single pads, a second beam test was conducted at the Trento Proton Therapy Center (Italy) with dedicated UFSD sensors segmented in strips. The results obtained at Trento facility show that for 97 cm distance between sensors and for all the energies tested (chosen in the 62-227MeV clinical range), the root mean square deviation between the measured beam energies with respect to the nominal ones corresponds to a range uncertainty < 1mm in water, as clinically required.