Faculty Profiles - SHIMIZU Hirohiko

Papers - SHIMIZU Hirohiko

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30aWD-5 Development of low energy particle detector using superconducting transition edge sensor (3)

Ohno M., Sato H., Morishima T., Mishima K., Ikeda T., Yamada S., Shimizu H.M.

Meeting Abstracts of the Physical Society of Japan Vol. 61.1.1 ( 0 ) page： 73 2006

30pXD-7 Development of Neutron Focusing Devices using Supermirrors with a Parabolic Surface for Thermal Neutrons

Ikeda K., Shinohara T., Hirota K., Sato H., Shimizu H.M., Hino M., Oku T., Suzuki J., Soyama K., Ohoyama K., Hiraka H.

Meeting Abstracts of the Physical Society of Japan Vol. 61.1.4 ( 0 ) page： 965 2006

30pXD-6 Jamin type cold-neutron interferometer for precise measurement of Aharonov-Casher effect

Seki Y., Funahashi H., Taketani K., Hino M., Kitaguchi M., Otake Y., Shimizu H.M.

Meeting Abstracts of the Physical Society of Japan Vol. 61.1.4 ( 0 ) page： 965 2006

30pXD-5 Development of a neutron polarizer based on a quadrupole magnet

Oku T., Yamada S., Suzuki J., Mishima K., Shinohara T., Ikeda K., Hirota K., Sato H., Shimizu H.M.

Meeting Abstracts of the Physical Society of Japan Vol. 61.1.4 ( 0 ) page： 965 2006

Development of Mach-Zehnder interferometer and "Coherent beam steering" technique for cold neutrons

Taketani K., Funahashi H., Seki Y., Hino M., Kitaguchi M., Maruyama R., Otake Y., Shimizu H.M.

Proceedings of the 8th International Symposium on Foundations of Quantum Mechanics in the Light of New Technology, ISQM-Tokyo 2005 page： 282 - 285 2006

Publisher：Proceedings of the 8th International Symposium on Foundations of Quantum Mechanics in the Light of New Technology, ISQM-Tokyo 2005

We are developing multilayer interferometer of Mach-Zehnder type for cold neutrons. To fulfill severe requirements for aligning the four mirrors, we utilize six solid-etalon-plates and a high precision flat base plate. New devices making use of magnetic birefringence have been developed and demonstrated to be useful for fine adjustment of superposition between the two paths labeled with neutron spin.

DOI： 10.1142/9789812773210_0060

Scopus

Polyimide Buffer Layer for STJ Photon Detector

Taino T., Yoshida M., Narisawa M., Myoren H., Kikuchi K., Nakagawa H., Aoyagi M., Sato H., Shimizu H. M., Takada S.

7TH EUROPEAN CONFERENCE ON APPLIED SUPERCONDUCTIVITY (EUCAS'05) Vol. 43 page： 1319 - 1321 2006

THz imaging with a linear array detector based on superconducting tunnel junctions

Ariyoshi, S; Otani, C; Dobroiu, A; Matsuo, H; Sato, H; Taino, T; Kawase, K; Shimizu, HM

CONFERENCE DIGEST OF THE 2006 JOINT 31ST INTERNATIONAL CONFERENCE ON INFRARED AND MILLIMETER WAVES AND 14TH INTERNATIONAL CONFERENCE ON TERAHERTZ ELECTRONICS page： 395 - 395 2006

Upgrade of the 32 m small-angle neutron scattering instrument SANS-U

Okabe, S; Nagao, M; Karino, T; Watanabe, S; Adachi, T; Shimizu, H; Shibayama, M

JOURNAL OF APPLIED CRYSTALLOGRAPHY Vol. 38 ( 6 ) page： 1035 - 1037 2005.12

Publisher：Journal of Applied Crystallography

The small-angle neutron scattering instrument, SANS-U, owned by the Institute for Solid State Physics, The University of Tokyo, has been upgraded. The SANS-U is a 32 m SANS instrument installed in 1991 at the guide hall of the JRR-3M research reactor of the Japan Atomic Energy Research Institute, and has been serving for inter-university cooperative research use since 1993. The major upgrades include (i) replacement of the two-dimensional area detector by a multi-wire type position-sensitive proportional counter, (ii) renewal of the operating system from a VAX and sequencers to an integrated PXI system controlled by LabVIEW-RT software, (iii) a focusing collimation system, and (iv) a variety of accessory equipment. These upgrades provide a wide dynamic range of neutron counting, user-friendly operation and real-time circular averaging of two-dimensional data. © 2005 International Union of Crystallography - all rights reserved.

DOI： 10.1107/S0021889805029201

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Detection of direct and indirect terahertz waves using a Nb-based superconducting tunnel junction

Otani C., Nakano R., Taino T., Shibuya T., Ariyoshi S., Myoren H., Sato H., Shimizu H.M., Takada S., Kawase K.

The Joint 30th International Conference on Infrared and Millimeter Waves and 13th International Conference on Terahertz Electronics, 2005. IRMMW-THz 2005 Vol. 1 page： 263 - 264 2005.12

Publisher：The Joint 30th International Conference on Infrared and Millimeter Waves and 13th International Conference on Terahertz Electronics, 2005. IRMMW-THz 2005

We are developing a broadband THz detectors using Nb-based superconducting tunnel junctions. We found two components in a current signal for 1-2 THz pulse input. From the comparison of results obtained for the signals, the frequency response for the different size of STJs and the STJs fabricated on different substrate materials, we demonstrate that they correspond to photons absorbed with the superconductor electrode (refered as 'direct' component) and phonons generated by photons absorbed with the substrate (refered as 'phonon-mediated' component). © 2005 IEEE.

Scopus

Small-angle neutron scattering study on the relation between abnormal brain protein structure and neuropathy; mechanism of the abnormal aggregation of microtubule-associated tau

Naito S., Mochizuki H., Yasuda T., Mizuno Y., Furusaka M., Ikeda S., Adachi T., Shimizu H.M., Suzuki J., Fujiwara S.

Polymer Preprints, Japan Vol. 54 ( 2 ) page： 4881 - 4882 2005.12

Publisher：Polymer Preprints, Japan

Tauopacy is the abnormal aggregation of tau which is one of the microtubule-associated proteins often observed in Alzheimer's disease and Parkinson's disease brain. Such an abnormal protein aggregation in cells causes cellular degeneration and death, and finally ends up with grave disorders. We synthesized human recombinant human tau and evaluated the structure in water by dynamic light scattering (DLS) and small-angle neutron scattering (SANS). SANS showed tau (46Kda,consisting of 448a.a.) behaved in water as if it were originally and highly polymerized rod-like fibers although the SDS-page showed tau was refined to a single molecule. After we confirmed tau heated with reducing agent showed a single dispersion by DLS, we observed the structure by SANS equipped with 40 fresnel lenses at a lower concentration, C*. The radius of gyration of the tau cluster was estimated to be 272 Å from the Gunier analysis on the SANS profile in the lower q ranges. We clarified that normal tau proteins form a huge globule cluster in water by self-assembly, furthermore, they form a fibril by intermolecular cystine cross-linking under oxidative environment.

Scopus

Development of superconducting sextupole magnet using HTS coated conductor for neutron-focusing device

KOYANAGI Kei, TOSAKA Taizo, ONO Michitaka, KURIYAMA Toru, WATANABE Ikuo, TSUCHIYA Kiyosumi, SUZUKI Jun-ichi, ADACHI Tomohiro, SHIMIZU M. Hirohiko

Vol. 73 page： 246 2005.11

The focal surface of the EUSO telescope

Kawasaki, Y; Bertaina, M; Ebisuzaki, T; Kajino, F; Miyazaki, Y; Nagano, M; Sakaki, N; Sato, M; Shimizu, HM; Takizawa, Y; Ameri, M; Catalano, O; Cuneo, S; Fontanelli, F; Gracco, V; Musico, P; Pallavicini, M; Petrolini, A; Pratolongo, R; Sannino, M; Bleurvacq, N; Cadoux, F; Chapron, C; Gorodetzky, P; Nedelec, P; Patzak, T; Plagnol, E; Takahashi, Y

INTERNATIONAL JOURNAL OF MODERN PHYSICS A Vol. 20 ( 29 ) page： 6890 - 6893 2005.11

Global measurement of lightning-associated transient luminous events (TLEs) from space

Sato, M; Ebisuzaki, T; Takizawa, Y; Kawasaki, Y; Sakaki, N; Bertaina, M; Shimizu, HM; Takahashi, Y; Adachi, T

INTERNATIONAL JOURNAL OF MODERN PHYSICS A Vol. 20 ( 29 ) page： 6903 - 6905 2005.11

Publisher：International Journal of Modern Physics A

In this study we present possibility of continuous measurements of lightning- associated transient luminous events (sprites, elves and blue jets) from the ISS altitude using the EUSO telescope. From global lightning data we estimated possible detection rates of lightning and TLEs. We also estimated photon numbers and optical spectra of TLEs in the near-ultraviolet region (300-400 nm) where the fluorescence emission caused by CRs exists. These results imply that EUSO has enough capabilities to monitor not only super-GZK CRs but also global lightning and TLEs. © World Scientific Publishing Company.

DOI： 10.1142/S0217751X05030454

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Photomultiplier development and wavelength shifter manufacturing to increase the detection of faint fluorescence signals

Bertaina, M; Ebisuzaki, T; Hirota, K; Kawasaki, Y; Sakaki, N; Sato, M; Shimizu, HM; Shinohara, T; Takizawa, Y

INTERNATIONAL JOURNAL OF MODERN PHYSICS A Vol. 20 ( 29 ) page： 6872 - 6874 2005.11

Publisher：International Journal of Modern Physics A

RIKEN has developed in collaboration with Hamamatsu a new type of Multi Anode Photomultiplier (MAPMT), R8900 series, with a large sensitive area of ∼83% of the physical surface. The performance of R8900 is reviewed in the following. RIKEN has also manufactured a new type of wavelength shifter (w.s.) film to shift near-UV light (330 ÷ 400 nm) to visible one. This film uses POPOP as a shifter and EPO-TEX as a substrate. The quantum efficiency of the film reaches ∼80%. © World Scientific Publishing Company.

DOI： 10.1142/S0217751X05030351

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Development of terahertz wave detector using superconducting tunnel junction

Taino, T; Hoshino, K; Nakano, R; Otani, C; Myoren, H; Kawase, K; Shibuya, T; Sato, H; Shimizu, HM; Takada, S

PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS Vol. 426 ( II ) page： 1731 - 1735 2005.10

Publisher：Physica C: Superconductivity and its Applications

We have developed a new terahertz (THz) wave detector using an Nb-based superconducting tunnel junction (STJ). The STJ consists of a Nb/Al/AlO x/Al/Nb structure on a single-crystal LiNbO3 substrate. Using LiNbO3 as a substrate, an irradiating THz wave is converted to phonons in LiNbO3, which has a relatively high absorption coefficient. The phonons propagating in the substrate reach the Nb base electrode of the STJ and break Cooper pairs. As a result, the THz wave can be detected as tunneling current signals in the STJ. THz waves from a widely tunable THz-wave parametric oscillator (TPO) were irradiated on to the STJ, which acted as a THz wave detector. The STJs were cooled to an operating temperature of 0.4 K using a 3He cryostat. We have observed STJ signals related to THz wave irradiations. In this paper, fabrication processes and characteristics of THz wave detectors using STJs are also discussed. © 2005 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.physc.2005.02.137

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Proton Polarization with Naphthalene Crystals by Integrated Solid Effect on Photoexcited Triplet State

Iinuma Masataka, Takahashi Yoshiro, Shaké Ippei, Oda Masahiro, Shimizu Hirohiko M., Masaike Akira, Yabuzaki Tsutomu

Journal of the Physical Society of Japan Vol. 74 ( 9 ) page： 2622 - 2630 2005.9

Language：English Publisher：THE PHYSICAL SOCIETY OF JAPAN

We have carried out detailed systematic studies of relaxation effects, which contribute to a significant improvement in proton polarization in a single crystal of naphthalene doped with pentacene. The experiments have been performed in a magnetic field of 3 kG at room temperature or at 77 K and with a pulsed dye laser or a pulsed N<SUB>2</SUB> laser. We have found that a relaxation rate in the presence of irradiation with visible light (λ=595 nm) is much smaller than that with ultraviolet light (λ=337 nm) at room temperature, although the absorption rate of visible light is much larger than that of ultraviolet light. By cooling the crystal, the slow motion of the naphthalene molecules, which is a dominant relaxation process, can be suppressed. Surprisingly, we have found that the relaxation time at 77 K in the presence of the dye laser becomes long, but still depends on the laser power. Our investigation has also indicated that both the longer relaxation time and the irradiation with the dye laser lead to a great improvement in the polarization of protons in the bulk of a crystal from 0.5% at room temperature to 32% at 77 K.

DOI： 10.1143/JPSJ.74.2622

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CiNii Research

Proton polarization with <i>p</i>-terphenyl crystal by integrated solid effect on photoexcited triplet state

Iinuma, M; Takahashi, Y; Shaké, I; Oda, M; Masaike, A; Yabuzaki, T; Shimizu, HM

JOURNAL OF MAGNETIC RESONANCE Vol. 175 ( 2 ) page： 235 - 241 2005.8

Publisher：Journal of Magnetic Resonance

We have carried out the experiments for polarizing protons in single crystals of p-terphenyl doped with 0.1 mol% pentacene. The experiments have been performed in a magnetic field of 3 kG at room temperature or at 77 K. We obtained the polarization of 1.3% for protons in bulk at room temperature by using a pulsed dye-laser with the wavelength of 590 nm, the average power of 150 mW, and the repetition rate of 50 Hz. The polarization at 77 K reached 18% by irradiation with the dye-laser of 500 mW, 50 Hz and the same wavelength. The polarization of protons was measured by the neutron transmission method also. The result was consistent with that measured by the nuclear magnetic resonance. © 2005 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.jmr.2005.04.011

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PubMed

A broad-band THz radiation detector using a Nb-based superconducting tunnel junction

Otani, C; Taino, T; Nakano, R; Hoshino, K; Shibuya, I; Myoren, H; Ariyoshi, S; Sato, H; Shimizu, HM; Takada, S; Kawase, K

IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY Vol. 15 ( 2 ) page： 591 - 594 2005.6

Publisher：IEEE Transactions on Applied Superconductivity

We have proposed and been developing a new broad-band terahertz (THz) radiation detector using a Nb-based superconducting tunnel junction (STJ). The STJ's were fabricated on LiNbO3 and LiTaO3 mono-crystal substrates. We radiated monochromatic THz pulses in the range 1-2 THz with the pulse repetition rate of 49 Hz, and successfully detected the corresponding periodic signals via a charge-sensitive preamplifier. The current signal obtained by the derivative of the output signal gave the time response of about 15-20 microseconds. The frequency response was compared with that of a conventional pyro-electric sensor. We found their frequency response showed the similar shape in frequency, demonstrating the flat response of the STJ detector in 1-2 THz. These results show that the detector can be used as a broad-band THz and far-infrared radiation detector above the frequency corresponding to the energy gap of the superconductor used for the base electrode. © 2005 IEEE.

DOI： 10.1109/TASC.2005.849950

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X-ray detection using superconducting tunnel junctions with polyimide insulation layer

Yoshida, M; Hoshino, K; Taino, T; Myoren, H; Takada, S; Kikuchi, K; Nakagawa, H; Aoyagi, M; Sato, H; Shimizu, HM

IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY Vol. 15 ( 2 ) page： 606 - 608 2005.6

Publisher：IEEE Transactions on Applied Superconductivity

We have fabricated Nb-based superconducting tunnel junctions (STJs) with Al trapping layers using the photosensitive polyimide insulation layer for X-ray detector. It is possible to simplify the fabrication process of the STJs, because the photosensitive polyimide is used as the insulation layer instead of conventional inorganic insulation films without an etching process in a vacuum chamber. The polyimide insulation layer expects to be stable for thermal cycling between 0.3 K and room temperature. The preliminary experiments of 5.9 keV radiation shows the energy resolution of 86 eV. © 2005 IEEE.

DOI： 10.1109/TASC.2005.849955

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Characterization of an STJ-based direct detector of submillimeter waves

Ariyoshi, S; Matsuo, H; Otani, C; Sato, H; Shimizu, HM; Kawase, K; Noguchi, T

IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY Vol. 15 ( 2 ) page： 920 - 923 2005.6

Publisher：IEEE Transactions on Applied Superconductivity

We have developed submillimeter-wave direct detectors employing niobium-based superconducting tunnel junctions (STJs), with broadband spectral response, high sensitivity and imaging capability. Spectral response peaked at 650 GHz with a fractional bandwidth of 14 percent, which fits one of the important atmospheric windows for an astronomical project. We also confirmed the linearity of the detector response in the dynamic range greater than 10 6. The measured coupling efficiency was about 0.2, which was lower than the expected value of 0.5. The measured noise current of the detector was 10 fA/√Hz, which agreed with the shot noise from the residual leakage current of 100 pA at 0.3 K. Resultant noise equivalent power (NEP) is 1.6 × 10-16 W/√Hz, that is less than the background photon fluctuation limit for ground-based submillimeter-wave observations. © 2005 IEEE.

DOI： 10.1109/TASC.2005.850119

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Papers - SHIMIZU Hirohiko