Radiograaff: a medium energy proton irradiation platform for radiobiological studies. Presentation and first results
Résumé
Radiograaff is a horizontal beam facility for radiobiological experiments with medium-energy protons which has been setup at the 4MV Van de Graaff accelerator of the Institut de Physique Nucléaire de Lyon. At this energy, the Relative Biological Effectiveness (in terms of α/αx ratio) of protons may amount to 2-6 [1] and RBE at 10% of cell inactivation was reported for V79 cell line to range between 1 and 1.6 [2]. Thus, this platform constitutes a tool to study the specific effects of high Linear Energy Transfer (LET) radiations to cells. For such macroscopic-irradiation facilities, the dose distribution over the cell samples has to be uniform with accuracy better than ±5% with a controlled dose rate (2 Gy/min for clinical interest). In addition, the variation of the LET between the entrance and the exit of the cells does not exceed 10%.