Thin low-gain avalanche detectors for particle therapy applications

none18The University of Torino (UniTO) and the National Institute for Nuclear Physics (INFN-TO) are investigating the use of Ultra Fast Silicon Detectors (UFSD) for beam monitoring in radiobiological experiments with therapeutic proton beams. The single particle identification approach of solid state detectors aims at increasing the sensitivity and reducing the response time of the conventional monitoring devices, based on gas detectors. Two prototype systems are being developed to count the number of beam particles and to measure the beam energy with time-of-flight (ToF) techniques. The clinically driven precision (< 1%) in the number of particles delivered and the uncertainty < 1 mm in the depth of penetration (range) in radiobiological experiments (up to 108 protons/s fluxes) are the goals to be pursued. The future translation into clinics would allow the implementation of faster and more accurate treatment modalities, nowadays prevented by the limits of state-of-the-art beam monitors. The experimental results performed with clinical proton beams at CNAO (Centro Nazionale di Adroterapia Oncologica, Pavia) and CPT (Centro di Protonterapia, Trento) showed a counting inefficiency <2% up to 100 MHz/cm2, and a deviation of few hundreds of keV of measured beam energies with respect to nominal ones. The progresses of the project are reported.noneVignati, A.; Donetti, M.; Fausti, F.; Ferrero, M.; Giordanengo, S.; Hammad Ali, O.; Mart Villarreal, O.A.; Mas Milian, F.; Mazza, G.; Monaco, V.; Sacchi, R.; Shakarami, Z.; Sola, V.; Staiano, A.; Tommasino, F.; Verroi, E.; Wheadon, R.; Cirio, R.Vignati, A.; Donetti, M.; Fausti, F.; Ferrero, M.; Giordanengo, S.; Hammad Ali, O.; Mart Villarreal, O. A.; Mas Milian, F.; Mazza, G.; Monaco, V.; Sacchi, R.; Shakarami, Z.; Sola, V.; Staiano, A.; Tommasino, F.; Verroi, E.; Wheadon, R.; Cirio, R

A new detector for the beam energy measurement in proton therapy: a feasibility study

Fast procedures for the beam quality assessment and for the monitoring of beam energy modulations during the irradiation are among the most urgent improvements in particle therapy. Indeed, the online measurement of the particle beam energy could allow assessing the range of penetration during treatments, encouraging the development of new dose delivery techniques for moving targets. Towards this end, the proof of concept of a new device, able to measure in a few seconds the energy of clinical proton beams (from 60 to 230 MeV) from the Time of Flight (ToF) of protons, is presented. The prototype consists of two Ultra Fast Silicon Detector (UFSD) pads, featuring an active thickness of 80 um and a sensitive area of 3 x 3 mm2, aligned along the beam direction in a telescope configuration, connected to a broadband amplifier and readout by a digitizer. Measurements were performed at the Centro Nazionale di Adroterapia Oncologica (CNAO, Pavia, Italy), at five different clinical beam energies and four distances between the sensors (from 7 to 97 cm) for each energy. In order to derive the beam energy from the measured average ToF, several systematic effects were considered, Monte Carlo simulations were developed to validate the method and a global fit approach was adopted to calibrate the system. The results were benchmarked against the energy values obtained from the water equivalent depths provided by CNAO. Deviations of few hundreds of keV have been achieved for all considered proton beam energies for both 67 and 97 cm distances between the sensors and few seconds of irradiation were necessary to collect the required statistics. These preliminary results indicate that a telescope of UFSDs could achieve in a few seconds the accuracy required for the clinical application and therefore encourage further investigations towards the improvement and the optimization of the present prototype

Characterization of a proton counter for particle therapy applications

A proton counter for particle therapy applications based on LGAD detectors was developed by the INFN and University of Torino

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 62–227 MeV clinical range), the root mean square deviation between the measured beam energies with respect to the nominal ones corresponds to a range uncertainty < 1 mm in water, as clinically require