Taichi Tokutake

Scintillation Properties of In Doped ZnO With Different In Concentrations

Using the liquid phase epitaxy (LPE) method we prepared the high crystalline quality In3+ doped ZnO thin film scintillators with different Indium concentration of 26, 53, and 141 ppm. We evaluated their optical properties and radiation response, because there are few reports of radiation response of In-doped ZnO scintillator. In order to imitate the scintillator application, we measured the alpha-ray excited luminescence spectra. The emission bands peaking around 375 and 500 nm were observed, and with an increment of In3+, the intensity of both bands decreases. In the measurement of light yield, we optically coupled the sample with PMT R7600 by a silicone grease, and excitation was provided by 241Am 5.5 MeV-rays. The samples showed of about 10% of the light yield of BGO scintillator which was used as a reference. Under the same excitation the scintillation decay was measured in all the samples as well.

Development of ZnO Based Charged Particle Monitor for Processing Facility

In the present paper, we describe the development of an α-ray imaging detector based on a ZnO single crystalline scintillator and a position-sensitive photomultiplier tube (PSPMT). The ZnO crystal was grown by the hydrothermal synthesis method with 2-in.- in diameter. The ZnO specimen was polished out to be 0.5 mm in thickness. After optically coupling with PSPMT, the crystal was irradiated with 241Am α-ray for evaluation of both spatial resolution and pulse height spectrum. Using the charge center of the gravity method, two-dimensional α-ray images were successfully obtained. The efficiency of the energy window in terms of imaging quality was also examined.

Evaluations of ZnO based α-ray imager

In the present paper, we describe the development of an α-ray imaging detector based on a ZnO single crystalline scintillator and a position-sensitive photomultiplier tube (PSPMT). The ZnO crystal was grown by the hydrothermal synthesis method with 2-inch-φ in diameter. The ZnO specimen was polished out to be 0.5 mm in thickness. After optically coupling with PSPMT, the crystal was irradiated with 241Am α-ray for evaluation of both spatial resolution and pulse height spectrum. Using the charge center of the gravity method, two-dimensional α-ray images were successfully obtained. The efficiency of the energy window in terms of imaging quality was also examined.

Comparative study of Ga, In, and Mg doped ZnO thin-film scintillator with Geiger mode APD

Ga 25, 55, and 552 ppm doped, In 25, 53, and 141 ppm doped, Mg 1, 5, 10, 13 mol% doped ZnO thin film scintillators were grown by the Liquid Phase Epitaxy (LPE) method. Their transmittance, α-ray induced emission spectra were evaluated. The transmittance reached to 80% at wavelength longer than 390 nm for all the crystals. Two emission lines appeared at 390 and 550 nm, due to the free and bound excitons, respectively. Coupled with Multi Pixel Photon Counter (MPPC), the light yield and decay time were evaluated.