Application of CR-39 in laser-driven ion acceleration experiments

Fukuda, Yuji; Kanasaki, Masato; Sakaki, Hironao; Hori, Toshihiko*; Tampo, Motonobu; Kondo, Kiminori; Kurashima, Satoshi; Kamiya, Tomihiro; Oda, Keiji*; Yamauchi, Tomoya*

Recently, CR-39 detectors have been widely used in the studies of laser-driven ion acceleration experiments. In such experiments, however, the energies of accelerated ions often exceed the detection threshold limit of the CR-39. Therefore, a simple method to detect high energy ions using the CR-39 is required. We have developed a new simple diagnosis method, namely a backscattering technique, for high energy ions by utilizing the combination of CR-39 detectors and plastic backscatters. Proof-of-principle experiments for the new method were carried out at the Takasaki Ion Accelerators for Advanced Radiation Application (TIARA) facility in JAEA, which delivered He ion beam with an energy of 100 MeV. The result shows that this method enables us to characterize high energy ion beams which energies are beyond the detection threshold limit of CR-39. High energy ions accelerated by using J-KAREN laser are successfully detected with this method.