Production of a fluorescence probe in ion-beam radiolysis of aqueous coumarin-3-carboxylic acid solution—2: Effects of nuclear fragmentation and its simulation with PHITS

The G(OH) values in aqueous coumarin-3-carboxylic-acid (3-CCA) solutions irradiated with 12C6+ beams having the energies of 135, 290 and 400 MeV/u were measured by a fluorescent method around the Bragg peak, with 0.6 mm intervals, and quartz cells of 1 cm optical lengths, at the Heavy Ion Medical Accelerator in Chiba, National Institute of Radiological Sciences (NIRS). For each ion, the G(OH) has been calculated as a function of dose average LET and position. The calculated results have been compared to measurements, and the results, reproducibility and reliability of the calculations are discussed in the paper.

► Therapeutic ion beam has energy of several hundred MeV/u because it is necessary for a few tens cm range.
► With such high energy, nuclear fragmentations of carbon ions occur resulting in production of lighter ions.
► In this study, OH yield in water radiolysis near the Bragg peak of therapeutic ion beams was measured.
► Measured yields are discussed considering nuclear fragmentation by PHITS code.