Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Kamiya, Tomihiro; Takano, Katsuyoshi; Ishii, Yasuyuki; Sato, Takahiro; Oikawa, Masakazu*; Okubo, Takeru; Haga, Junji*; Nishikawa, Hiroyuki*; Furuta, Yusuke*; Uchiya, Naoyuki*; et al.
Nuclear Instruments and Methods in Physics Research B, 267(12-13), p.2317 - 2320, 2009/06
Times Cited Count：7 Percentile：47.15(Instruments & Instrumentation)
n and np diodes by heavy ion micro beamsOshima, Takeshi; Iwamoto, Naoya; Onoda, Shinobu; Kamiya, Tomihiro; Kawano, Katsuyasu*
Nuclear Instruments and Methods in Physics Research B, 267(12-13), p.2189 - 2192, 2009/06
Times Cited Count：9 Percentile：53.48(Instruments & Instrumentation)In this study, pn and np diodes were fabricated on 6H-SiC epitaxial layers. The transient currents induced in these diodes by the incidence of tens MeV range heavy ion micro beams were collected by the Transient Ion Beam Induced Current (TIBIC) measurement system. The value of Charge Collection Efficiency (CCE) for the SiC diodes was obtained by analyzing the transient currents. As a result using 9 MeV-oxygen ions, the CCE value of around 85 % was obtained from both pn and np diodes. Since the CCE value includes non-ionizing energy loss as well as the decay of charge in the measurement system, the obtained CCE value suggests that SiC pn as well as np diodes are suitable for particle detectors. For ion species dependence, the values of CCE for both pn and np diodes decrease with increasing atomic number of incident ions. This decrease in CCE by heavy ion incidence can be interpreted in terms of Auger recombination in dense electron-hole pairs.
Hirao, Toshio; Onoda, Shinobu; Oikawa, Masakazu*; Sato, Takahiro; Kamiya, Tomihiro; Oshima, Takeshi
Nuclear Instruments and Methods in Physics Research B, 267(12-13), p.2216 - 2218, 2009/06
Times Cited Count：11 Percentile：59.85(Instruments & Instrumentation)Single-Event Effects (SEEs) are triggered when an energetic heavy ion traverses a sensitive area in electric devices. Since the SEEs occur due to dense charge which is created along to ion track within the order of picoseconds, the measurement of such a high speed current signals is very important. Furthermore, the size of dense charge and their concentration depend on LET as well as energy of incident ions. This means that the transient currents induced in electronic devices by incidence of ions with various energies and LETs should be investigated to clarify the mechanism of SEEs for electronic devices. Especially, the evaluations using heavy ions with high energies more than a several hundred MeVs are very important to understand the mechanism of SEEs observed in space. For this aim, we have developed an irradiation system of focused heavy ion microbeams at a several hundreds of MeVs at JAEA. In this paper, we study transient currents induced in Si photodiodes using the focused heavy ion microbeam irradiation system. The mapping of charge collected from the photodiodes irradiated with 260 MeV 
Ne
ion microbeams, which is firstly observed in the world, will be presented. In addition, the difference in transient currents induced by ions at several hundred MeVs from ions at tens MeVs is discussed using TCAD (Technology Computer Aided Design) and GUN theorem.
Kurashima, Satoshi; Yoshida, Kenichi; Oikawa, Masakazu*; Sato, Takahiro; Miyawaki, Nobumasa; Yuyama, Takahiro; Okumura, Susumu; Kashiwagi, Hirotsugu; Ishibori, Ikuo; Nara, Takayuki; et al.
Nuclear Instruments and Methods in Physics Research B, 267(12-13), p.2024 - 2027, 2009/06
Times Cited Count：10 Percentile：56.67(Instruments & Instrumentation)A heavy-ion microbeam with energy of hundreds of MeV is utilized for research in biotechnology and materials science at the JAEA AVF cyclotron facility. Beam users need microbeams providing a wide range of linear energy transfer (LET). In order to vary LET widely, we have to change the ion species and/or energy. A cocktail beam acceleration technique is frequently used to change the ion species quickly. Ion species and energy can be changed by slightly shifting the acceleration frequency. The cocktail acceleration technique has been applied to microbeam production for quick change of ion species of a microbeam. As a result, we have succeeded to reduce considerably microbeam changing time to within 30 minutes between a 260 MeV Ne and a 520 MeV Ar. No deterioration of a microbeam spot size has been confirmed using a secondary electron microscope image of a copper mesh.
Ishii, Yasuyuki; Chiba, Atsuya; Yokoyama, Akihito; Agematsu, Takashi; Kamiya, Tomihiro; Mizuhashi, Kiyoshi
no journal, ,
Okubo, Takeru; Ishii, Yasuyuki
no journal, ,
Sato, Takahiro; Oikawa, Masakazu*; Kamiya, Tomihiro
no journal, ,
This study aims to measure three-dimensional distribution of trace elements in a minute sample. Such a distribution was acquired by reconstruction of projection images in much the same way as X-ray CT using many two-dimensional images of micro-PIXE taken from various directions. When the image reconstruction technique is applied to in-air micro-PIXE analysis, the X-ray yields must be corrected using X-ray production cross sections, X-ray attenuation coefficients, energies of incident particles, and three-dimensional density of major elements in the analysis target. In this study, STIM-CT was used to measure the density map of the target. The in-air micro-PIXE images of sulfur and iron in a minute target were corrected using coefficients calculated from the three-dimensional density map. Thus the three-dimensional distribution of sulfur and iron in the target was successfully measured by the combination of STIM-CT and in-air micro-PIXE.
