Orateur
Description
Hadron therapy is an innovative and promising mode of radiotherapy for cancer treatment. Its advantages are of both physical as well as biological nature. Alongside the physical advantages as precise dose delivery due to the nature of the ions stopping power, ion beams additionally show an increased relative biological effectiveness (RBE), which is defined as the ratio of the irradiated dose of ions to that of a reference photon energy that would be required to result in the same biological effect for both. For treatment planning, a reliable estimation of RBE of such ion beams to irradiated tissue is required. This type of access to experimentally measured quantities is essential but there is a lack of practical experimental tool to characterize this quantity, which could fulfil all severe requirements for radiation quality assurance in the hadron therapy. To address this issue, DIADEM collaboration is developing a new microdosimetric system based on scCVD diamond membrane sensor. Three generations of scCVD diamond membranes based sensors were designed and fabricated including: (i) p+ sensor where active micro-sensitive volumes (microSVs) are created by the local semiconductor junction formation, (ii) Guard-ring (GR) sensor, where microSVs are formed by a guard-ring electrode limiting the active area (iii) fully 3D sensor, where completely isolated microSVs made of scCVD diamond are embedded into non-electrically active resine. The charge transport properties of fabricated sensors were studied with the IBIC technique at three microbeam facilities including: CENBG Bordeaux, RBI Zagreb, and ANSTO Sydney, giving an insight into the performances of the sensors in well-controlled conditions as well as its response to the various projectiles with large span of the LET. Finally, sensors were integrated onto a specially designed pcb with dedicated electronics to perform clinical proton and carbon beam characterization, along with simultaneous measurement of macroscopic dose and lineal energy transfer required for the RBE calculations.
