PRAGUE project

Measuring and verifying the reliability and stability of the dosimetric properties of a radiotherapeutic beam, is the most important task of any external-beam radiotherapy quality assurance program. The beam characteristics (and associated reliability) can be assessed in terms of several different parameters, such as the percentage depth-dose distribution, flatness, symmetry, and absolute dose output. The depthdose distribution measure is today performed, adopting commercial systems whose main advantage is the short operational time. Research in this field is currently focused on the accuracy increase while maintaining the overall procedure time as fast as possible. The aim of PRAGUE (Proton RAnGe measure Using silicon carbidE) project is to design and construct a detector, based on a new generation of Silicon Carbide (or SiC) devices, to measure proton depth dose distributions in real-time and with high spatial resolution (order of 10 μm). The extreme radiation hardness of such devices and the independence of their response with the proton beam energy, makes them capable to operate with conventional clinical hadrontherapy beams as well as laser-driven ion beams, where extremely high dose rates are delivered. The detector will be composed by a stack of new generation, large area (~15 mm^2) SiC devices with an active thickness of 10 μm. These extremely small sensitive thickness can be achieved thanks to a new original technique, based on an electrochemical attach, developed at IMM-CNR (Institute for Microelectronics and Microsystem - Consiglio Nazionale Delle Ricerche). PRAGUE has the potential to radically change the panorama of the current research in relative dosimetry with extreme intense dose rate. At today, in fact, a real-time solid-state detector to measure depth-dose distributions curves (energy independence) with such spatial resolution and radiation-hardness characteristics doesn’t exist. The developed technology will allow obtaining dose information shot-to-shot in the biological sample with a precision of the order of 3% as required by international protocols for the patient treatments (IAEA TRS-398).