@misc{oai:repo.qst.go.jp:00066532,
 author = {錦戸, 文彦 and 高田, 英治 and 野上, 光博 and 鋪田, 嚴 and 新田, 宗孝 and 蛭海, 元貴 and 山谷, 泰賀 and 錦戸 文彦 and 高田 英治 and 野上 光博 and 鋪田 嚴 and 新田 宗孝 and 蛭海 元貴 and 山谷 泰賀},
 month = {Oct},
 note = {Organic photodiodes (OPDs) are thin, flexible, printable and inexpensive devices. Therefore, radiation detectors using OPDs are expected to be suitable for carbon therapy dosimeters. However, characteristics of the OPDs for high energy heavy ion measurements have not been investigated deeply. Therefore, we are investigating OPDs as radiation detectors for heavy ion beam irradiation.
The device structure of the OPD detectors used in the experiments consisted of layers of IZO (100 nm)/ PEDOT: PSS (30 nm) / PCBM: P3HT (200 nm) / Al (70 nm).  The sizes of the sensing surface areas for the evaluated detectors were 1 mm × 1 mm, 2 mm × 2 mm, 3 mm × 3 mm and 8 mm × 4 mm. The OPDs were fabricated on 10 mm × 10 mm black ABS boards by spin coating; fabrication was done 3 days before an experiment. In the evaluation experiment, the OPD detectors were mounted in aluminum boxes for shielding. The Al and IZO electrodes were connected to readout wires with silver paste. Bias voltage was not applied in any measurements. The experiment was performed in the PH2 course of HIMAC at NIRS. The energy of the 12C beam was 290 MeV/u. The OPDs were irradiated by the 12C beam through an ion chamber to normalize the number of irradiated particles. The beam intensity was 106 to 108 particles per second (pps). The diameter of the 12C beam was 1 cm at the OPD. 
 We measured charges induced by the carbon beam irradiation with all the fabricated OPD detectors. Beam spill structure of 3.3 s cycle could be clearly observed at 108 pps with 0.1 s interval. The OPD detectors had similar beam intensity dependence as a reference ionization chamber and sufficient linearity to beam intensity under 1×108 pps. Bragg curves and Bragg peaks were clearly observed for all OPDs. However, compared with the ionization chamber, the results of the OPD detectors were saturated around the Bragg peak., The 2017 Nuclear Science Symposium and Medical Imaging Conference, together with the 24th Symposium on Room-Temperature X- and Gamma-Ray Detectors},
 title = {Organic photodiode detectors for heavy ion beam measurement},
 year = {2017}
}