M. Yokota

Kanagawa University, Yokohama, Kanagawa, Japan

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Publications (4)3.28 Total impact

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    ABSTRACT: We have developed radiation detectors using the new synthetic diamonds. The diamond detector has an advantage for observations of "low/medium" energy gamma rays as a Compton telescope. The primary advantage of the diamond detector can reduce the photoelectric effect in the low energy range, which is background noise for tracking of the Compton recoil electron. A concept of the Diamond Compton Telescope (DCT) consists of position sensitive layers of diamond-striped detector and calorimeter layer of CdTe detector. The key part of the DCT is diamond-striped detectors with a higher positional resolution and a wider energy range from 10 keV to 10 MeV. However, the diamond-striped detector is under development. We describe the performance of prototype diamond detector and the design of a possible DCT evaluated by Monte Carlo simulations. Comment: 4 pages, 8 figures, Accepted for publication in Astrophysics and Space Science, proceeding of "The Multi-Messenger Approach to High-Energy Gamma-Ray Sources", Barcelona, July 4-7, 2006
    Astrophysics and Space Science 07/2007; · 2.06 Impact Factor
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    ABSTRACT: Diamonds have attractive properties for use as radiation detectors. Recent advances in diamond fabrication techniques have made it possible to produce almost perfect single crystal materials that have electrical properties suitable for radiation detectors. We therefore developed detectors made of high-purity synthetic IIa diamonds grown by a high-pressure, high-temperature method and investigated their basic properties. These detectors have Schottky and Ohmic electrodes, and the leakage current is less than 20 pA with reverse bias voltages up to 2.4 kV, demonstrating that the detector withstands high bias voltage. The results of testing the electrical properties show that the electrodes work well. The best detector achieved an energy resolution of 15.4 keV (FWHM) for 5.486 MeV alpha particles from <sup>241</sup>Am.
    IEEE Transactions on Nuclear Science 05/2006; · 1.22 Impact Factor
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    ABSTRACT: Radiation detector made of synthetic diamond has many advantages as high resolution and pulse mode radiation detector. Synthetic diamond detector has been investigated, its characteristics, with electric tests and radiation sources in laboratories. In order to investigate more detail of its character, high energy heavy ion beams from HIMAC were irradiated to the synthetic diamond detector. Because these beams can penetrate the diamond detector and give it much deposit energy, characteristic at deeper part of synthetic diamond detector can be investigated. Using heavy ion beams like iron 500 MeV/u, silicon 800 MeV and so on, saturation curve for bias voltage, polarization effect, which is a phenomenon of decreasing of output signals and energy resolution of a diamond detector for deposit energy were investigated.
    Nuclear Science Symposium Conference Record, 2005 IEEE; 11/2005
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    [show abstract] [hide abstract]
    ABSTRACT: Diamonds have attractive properties for use as radiation detectors. Recent advances in diamond fabrication techniques have made it possible to produce almost perfect single crystal materials that have electrical properties suitable for radiation detectors. We developed detectors made of high-purity synthetic IIa diamond grown by the high-pressure, high-temperature method and investigated their basic properties. The leakage current is less than 20 pA with reverse bias voltages up to 2.4 kV, and the diode current is 0.1 μA with 1 V forward bias voltage. The energy resolution for the best detector is 15.4 keV (FWHM) for 5.486 MeV alpha particles from <sup>241</sup>Am.
    Nuclear Science Symposium Conference Record, 2004 IEEE; 11/2004