2007, プラズマ・核融合学会賞 貢献賞　　　　　　　　　　　　　　　
Japan

2007, JSPF Award for Notable Contribution to our communitiy　　　　　　　　　　　　　　　

Deuterium and helium desorption/retention properties of low-activation vanadium alloys possible for reuse in a short time in fusion reactors
Yuji Yamauchi, Yusuke Tanoue, Kazuki Keta, Takuya Nagasaka, Jingjie Shen, Satoshi Tomioka, Yutaka Matsumoto
Nuclear Materials and Energy, Jun. 2024
Scientific journal

Wavefront restoration from lateral shearing data using spectral interpolation
Satoshi Tomioka, Naoki Miyamoto, Yuji Yamauchi, Yutaka Matsumoto, Samia Heshmat
Applied Optics, 10 Oct. 2023
Scientific journal

Localized compensator phase unwrapping algorithm based on flux conservable solver
Samia Heshmat, Satoshi Tomioka, Shusuke Nishiyama, Arata Hirokami
Journal of Computational Science, Jul. 2022
Scientific journal

Accurate numerical method to solve flux distribution of Poisson’s equation
Arata Hirokami, Samia Heshmat, Satoshi Tomioka
Mathematics and Computers in Simulation, 190, 329, 342, Elsevier BV, Dec. 2021, [Peer-reviewed], [Corresponding author]
Scientific journal, 11047291

Technical Note: Range verification of pulsed proton beams from fixed-field alternating gradient accelerator by means of time-of-flight measurement of ionoacoustic waves.
Yuta Nakamura, Taisuke Takayanagi, Tomoki Uesaka, Mehmet Burcin Unlu, Yasutoshi Kuriyama, Yoshihiro Ishi, Tomonori Uesugi, Masanori Kobayashi, Nobuki Kudo, Sodai Tanaka, Kikuo Umegaki, Satoshi Tomioka, Taeko Matsuura
Medical physics, 48, 9, 5490, 5500, Sep. 2021, [International Magazine]
English, Scientific journal, PURPOSE: Ionoacoustics is one of the promising approaches to verify the beam range in proton therapy. However, the weakness of the wave signal remains a main hindrance to its application in clinics. Here we studied the potential use of a fixed-field alternating gradient accelerator (FFA), one of the accelerator candidates for future proton therapy. For such end, magnitude of the pressure wave and range accuracy achieved by the short-pulsed beam of FFA were assessed, using both simulation and experimental procedure. METHODS: A 100 MeV proton beam from the FFA was applied on a water phantom, through the acrylic wall. The beam range measured by the Bragg peak (BP)-ionization chamber (BPC) was 77.6 mm, while the maximum dose at BP was estimated to be 0.35 Gy/pulse. A hydrophone was placed 20 mm downstream of the BP, and signals were amplified and stored by a digital oscilloscope, averaged, and low-pass filtered. Time-of-flight (TOF) and two relative TOF values were analyzed in order to determine the beam range. Furthermore, an acoustic wave transport simulation was conducted to estimate the amplitude of the pressure waves. RESULTS: The range calculated when using two relative TOF was 78.16 ± 0.01 and 78.14 ± 0.01 mm, respectively, both values being coherent with the range measured by the BPC (the difference was 0.5-0.6 mm). In contrast, utilizing the direct TOF resulted in a range error of 1.8 mm. Fivefold and 50-fold averaging were required to suppress the range variation to below 1 mm for TOF and relative TOF measures, respectively. The simulation suggested the magnitude of pressure wave at the detector exceeded 7 Pascal. CONCLUSION: A submillimeter range accuracy was attained with a pulsed beam of about 21 ns from an FFA, at a clinical energy using relative TOF. To precisely quantify the range with a single TOF measurement, subsequent improvement in the measuring system is required.

On-line range verification for proton beam therapy using spherical ionoacoustic waves with resonant frequency
Taisuke Takayanagi, Tomoki Uesaka, Yuta Nakamura, Mehmet Burcin Unlu, Yasutoshi Kuriyama, Tomonori Uesugi, Yoshihiro Ishi, Nobuki Kudo, Masanori Kobayashi, Kikuo Umegaki, Satoshi Tomioka, Taeko Matsuura
Scientific Reports, 10, 20385, Springer Science and Business Media LLC, Dec. 2020, [Peer-reviewed]
English, Scientific journal, In contrast to conventional X-ray therapy, proton beam therapy (PBT) can confine radiation doses to tumours because of the presence of the Bragg peak. However, the precision of the treatment is currently limited by the uncertainty in the beam range. Recently, a unique range verification methodology has been proposed based on simulation studies that exploit spherical ionoacoustic waves with resonant frequency (SPIREs). SPIREs are emitted from spherical gold markers in tumours initially introduced for accurate patient positioning when the proton beam is injected. These waves have a remarkable property: their amplitude is linearly correlated with the residual beam range at the marker position. Here, we present proof-of-principle experiments using short-pulsed proton beams at the clinical dose to demonstrate the feasibility of using SPIREs for beam-range verification with submillimetre accuracy. These results should substantially contribute to reducing the range uncertainty in future PBT applications.

Desingularization of matrix equations employing hypersingular integrals in boundary element methods using double nodes
Satoshi Tomioka, Shusuke Nishiyama, Yutaka Matsumoto, Naoki Miyamoto
Engineering Analysis with Boundary Elements, 106, 493, 504, Sep. 2019, [Peer-reviewed], [Lead author]
English, Scientific journal, 11047291

Phase Extraction from Single Interferogram Including Closed-Fringe Using Deep Learning
Daichi Kando, Satoshi Tomioka, Naoki Miyamoto, Ryosuke Ueda
Applied Sciences, 9, 17, 3529, 3529, {MDPI} {AG}, 28 Aug. 2019, [Peer-reviewed], [Corresponding author]
English, Scientific journal, In an optical measurement system using an interferometer, a phase extracting technique from interferogram is the key issue. When the object is varying in time, the Fourier-transform method is commonly used since this method can extract a phase image from a single interferogram. However, there is a limitation, that an interferogram including closed-fringes cannot be applied. The closed-fringes appear when intervals of the background fringes are long. In some experimental setups, which need to change the alignments of optical components such as a 3-D optical tomographic system, the interval of the fringes cannot be controlled. To extract the phase from the interferogram including the closed-fringes we propose the use of deep learning. A large amount of the pairs of the interferograms and phase-shift images are prepared, and the trained network, the input for which is an interferogram and the output a corresponding phase-shift image, is obtained using supervised learning. From comparisons of the extracted phase, we can demonstrate that the accuracy of the trained network is superior to that of the Fourier-transform method. Furthermore, the trained network can be applicable to the interferogram including the closed-fringes, which is impossible with the Fourier transform method., 11047291

Phase extraction from interferogram using machine learning
Daichi Kando, Satoshi Tomioka
Electronic Imaging, Image Processing: Algorithms and Systems XVII, 2019, 11, 259-1, 259-5, Feb. 2019, [Peer-reviewed], [Corresponding author]
English, International conference proceedings, 11047291

Direct Flux Method to Solve Flux Distribution of Two-dimensional Poisson's Equation
Arata Hirokami, Satoshi Tomioka
The 37th JSST Annual International Conference on Simulation Technology, 109, 112, Sep. 2018, [Peer-reviewed], [Last author, Corresponding author]
English, Scientific journal, 11047291

Accurate Numerical Method to Solve Flux Distribution of Two-dimensional Poisson's Equation
Arata Hirokami, Satoshi Tomioka
電磁界理論研究会, 118, 67, 17, 22, May 2018, [Last author, Corresponding author]
Japanese, 11047291

Effects of broken solenoidal condition of magnetic field in MHD simulation for large helical device plasmas
W. Takado, Y. Matsumoto, K. Y. Watanabe, S. Tomioka, S. Oikawa
PHYSICS OF PLASMAS, 24, 9, 092506:1, 7, AMER INST PHYSICS, Sep. 2017, [Peer-reviewed]
English, Scientific journal, We studied the effects of the broken solenoidal condition of a magnetic field in linear magnetohydrodynamics (MHD) simulations based on a real coordinate system for Large Helical Device plasmas. Artificial errors of various orders in this condition were introduced into linear MHD simulations and compared. Spurious Fourier modes were observed to be dominant because of the error in the condition. We suggested a criterion, which is expressed as the condition that the ratio of the error force to the Lorentz force is much smaller than 100%, for estimating an acceptable limit of the solenoidal condition error through the simulation results. The effects of a large error in the condition of the analysis of a specified single-mode instability were investigated in addition. Adding a large error in the condition resulted in certain undesirable modes becoming dominant, whereas the desirable mode did not dominate. Thus, a large error in the condition can be harmful to analysis with a focus on specified modes. Published by AIP Publishing.

Weighted reconstruction of three-dimensional refractive index in interferometric tomography
Satoshi Tomioka, Shusuke Nishiyama, Naoki Miyamoto, Daichi Kando, Samia Heshmat
APPLIED OPTICS, 56, 24, 6755, 6764, OPTICAL SOC AMER, Aug. 2017, [Peer-reviewed], [Lead author]
English, Scientific journal, Interferometric tomography can reconstruct 3D refractive-index distributions through phase-shift measurements for different beam angles. To reconstruct a complex refractive-index distribution, many projections along different directions are required. For the purpose of increasing the number of the projections, we earlier proposed a beam-angle-controllable interferometer with mechanical stages; however, the quality of reconstructed distribution by conventional algorithms was poor because the background fringes cannot be precisely controlled. To improve the quality, we propose a weighted reconstruction algorithm that can consider projection errors. We demonstrate the validity of the weighted reconstruction through simulations and a reconstruction from experimental data for three candle flames. (C) 2017 Optical Society of America, 11047292

Effects of the Broken Solenoidal Condition of a Perturbed Magnetic Field in a MHD Simulation for the LHD
Takado Wataru, Matsumoto Yutaka, Watanabe Kiyomasa, Tomioka Satoshi, Oikawa Shun-ichi
Meeting Abstracts of the Physical Society of Japan, 72.2, 132, 132, The Physical Society of Japan, 2017
Japanese

Introduction of the vector potential to a linear MHD simulation code based on a real coordinate system
W. Takado, Y. Matsumoto, K. Y. Watanabe, S. Tomioka, S. Oikawa
PHYSICS OF PLASMAS, 23, 10, 102509:1, 5, AMER INST PHYSICS, Oct. 2016, [Peer-reviewed]
English, Scientific journal, Here, the vector potential was introduced to a linear magnetohydrodynamics (MHD) simulation code, and the modified and original simulation results were compared. The effects of the broken solenoidal condition on the perturbed magnetic field in linear MHD simulations based on real coordinates were investigated. The results showed that the modified code can successfully remove the error in this condition, and the modified code was confirmed to work appropriately. Incorrect results can be yielded by an error in the condition, especially in analyses of the mode structure. Published by AIP Publishing.

Influence of mirror size on ringdown frequency in cavity-ringdown spectroscopy of slender premixed burner flame
Kazunori Zaima, Satoshi Tomioka, Koichi Sasaki
JAPANESE JOURNAL OF APPLIED PHYSICS, 54, 8, 088005:1, 3, IOP PUBLISHING LTD, Aug. 2015, [Peer-reviewed]
English, Scientific journal, We applied near-infrared cavity-ringdown absorption spectroscopy to a slender premixed burner flame with the intention of measuring the density of OH radicals. We found that the ringdown frequency was increased by the flame even when the laser wavelength was detuned from absorption lines. The additional ringdown frequency was dependent on the diameter of cavity mirrors, even though the expected spot size of the laser beam inside the cavity was much smaller than the mirror diameter. (C) 2015 The Japan Society of Applied Physics

Three-dimensional gas temperature measurements by computed tomography with incident angle variable interferometer
Satoshi Tomioka, Shusuke Nishiyama, Samia Heshmat, Yasuhiro Hashimoto, Kodai Kurita
COMPUTATIONAL IMAGING XIII, 9401, 0J01, 0J10, SPIE-INT SOC OPTICAL ENGINEERING, 2015, [Peer-reviewed], [Lead author]
English, International conference proceedings, This paper presents a method to measure three-dimensional gas temperature distribution without inserting a probe into the gas using techniques of computed tomography and optical interferometry. The temperature distribution can be reconstructed from a set of two-dimensional optical difference images for which the incident angle of each distribution differs. The each optical difference is measured by an interferometer with four mirrors which are movable and rotatable to control the incident angle. The temperature measurement system has two kinds of errors. The first is the error in the reconstruction caused by the limited angle of projection; the direction of the incident angle is limited in a certain region because of the limited arrangements of mirrors. The second is the errors in an evaluation of the projection data, which is the two-dimensional optical difference distribution, which are included in steps to evaluate the optical difference; a carrier frequency detection of background fringe, a carrier component filtering, phase unwrapping and so on. This paper shows improvements of accuracy of the reconstruction by adding a certain projection data to the original data set, and also the improvements of the evaluation of the optical difference using newly developed algorithms to evluate the optical differences., 11047293

Performance Evaluation of Phase Unwrapping Algorithms for Noisy Phase Measurements
Samia Heshmat, Satoshi Tomioka, Shusuke Nishiyama
INTERNATIONAL JOURNAL OF OPTOMECHATRONICS, 8, 4, 260, 274, TAYLOR & FRANCIS INC, Oct. 2014, [Peer-reviewed], [Corresponding author]
English, Scientific journal, Phase unwrapping still plays an important role in the optical metrology field. The phase unwrapping process has direct influence on the accuracy of final results. The aim of this article is to evaluate the performance of several well-known phase unwrapping algorithms for noisy phase measurement. The results of the examined algorithms on simulated and real phase data are presented, and the conclusions regarding the performances of each studied algorithm are given., 11047293

Weighted denoising for phase unwrapping
Satoshi Tomioka, Shusuke Nishiyama
IMAGE PROCESSING: ALGORITHMS AND SYSTEMS XII, 9019, 0M1, 0M10, SPIE-INT SOC OPTICAL ENGINEERING, 2014, [Peer-reviewed], [Lead author]
English, International conference proceedings, In order to measure the optical distance of the object that changes rapidly over time, Fourier transform method is appropriate because it requires only a single interferogram. In the measurements of such fast phenomena, the thermal noise by the camera to record the interferogram results in a significant error and the signal becomes weak owing to the short exposure time of the camera. When the noise level is high, a process to denoise wrapped phase should be added before phase unwrapping in order to obtain an optical distance distribution. The thermal noise has a uniform spatial distribution; however, the signal depends on a profile of the incident wave to the interferometer. This means that the signal to noise ratio has a spatial distribution. This paper proposes the denoising method that can take account of the weight of the data that depends on the signal intensity distribution. In order to determine the denoised phase, two cost functions are examined. One is a complex-valued cost function that can ensure convergence of iterative method to obtain the stationary point; however, it is not proved that both the real part and the imaginary part are minimized at the stationary point. The other is a real-valued cost function that cannot ensure the convergence but it minimizes the cost function at the stationary point. The numerical simulation demonstrates the validity of the weighted denoising and the applicability of the cost functions., 11047293

Carrier peak isolation from single interferogram using spectrum shift technique
Tomioka, Satoshi, Nishiyama, Shusuke, Heshmat, Samia
Applied Optics, 53, 25, 5620, 5631, OPTICAL SOC AMER, Sep. 2014, [Peer-reviewed], [Lead author]
English, Scientific journal, This paper presents a new method to obtain a wrapped phase distribution from a single interferogram with a spatial carrier modulation. The Fourier transform of the interferogram has three peaks: one is a dc peak around the origin in the Fourier domain, and the other two are carrier peaks that have information of phase modulation by an object placed in the interferometer. Since the wrapped phase can be evaluated by one of the two carrier peaks, the dc peak and the adjoint peak that is the other peak of two carrier peaks should be removed by filters. The proposed filtering process consists of two stages: dc peak filtering and adjoint peak filtering. A spectrum shift filter based on symmetrical characteristics of the spectrum is applied in both stages as a basic filter that can remove most of the undesired spectrum. An additional two filters are applied to remove the remaining spectrum. The new method can automatically isolate the carrier peak, even when the boundary of peaks is not very clear. Numerical evaluations of simulation data and experimental data demonstrate that the proposed method can successfully isolate the carrier peak. (C) 2014 Optical Society of America, 11047293

Phase extraction and unwrapping using rotational and direct compensators for digital hologram
Heshmat, Samia, Tomioka, Satoshi, Nishiyama, Shusuke
Optical Engineering, 52, 10, 101910-1, 8, SPIE-SOC PHOTO-OPTICAL INSTRUMENTATION ENGINEERS, Oct. 2013, [Peer-reviewed], [Corresponding author]
English, Scientific journal, The growing interest in the applications of digital holography interferometry has led to an increasing demand for reliable phase unwrapping techniques. In digital holography, the phase carries three-dimensional surface information about the object. However, phase mapping is ambiguous as the extracted phase is returned in a form that suffers from 2 pi phase jumps. Furthermore, the presence of noise in the measured data, in which many singular points (SP) are found, often makes general phase unwrapping algorithms fail to produce accurate unwrapped results. Therefore, it is necessary to use a powerful phase unwrapping method to recover the desired smooth phase surface. For this reason, we developed a phase unwrapping algorithm that is applicable to digital hologram maps. The developed algorithm solves the singularity problem caused by SPs as a result of compensating its effect by using rotational and direct compensators. We show a difference in performance between our developed phase unwrapping algorithm and other well known phase unwrapping methods for digital holographic data. In addition, the methods to extract phase information of the object from hologram maps are also investigated. Results show that the developed algorithm gives satisfactory unwrapped results with low computational time cost. (C) The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License., 11047293

Performance Evaluation of Phase Unwrapping Algorithms for Noisy Measurements
Samia Heshmat, Satoshi Tomioka, Shusuke Nishiyama
FRINGE 2013 - 7th International Workshop on Advanced Optical Imaging and Metrology, 155, 160, 2013, [Peer-reviewed], [Corresponding author]
English, International conference proceedings, 11047293

Rotational and direct compensation for digital hologram phase unwrapping
Samia Heshmat, Satoshi Tomioka, Shusuke Nishiyama
Speckle 2012: V International Conference on Speckle Metrology, SPIE, 11 Sep. 2012, [Peer-reviewed], [Corresponding author]
English, International conference proceedings, 11047293

Nondestructive three-dimensional measurement of gas temperature distribution by phase tomography
Satoshi Tomioka, Shusuke Nishiyama
COMPUTATIONAL IMAGING X, 8296, 17_1, 9, SPIE-INT SOC OPTICAL ENGINEERING, 2012, [Peer-reviewed], [Lead author]
English, International conference proceedings, This study presents a nondestructive three-dimensional (3D) measurement of gas temperature distribution around a heater. The distribution is obtained by a coupling method of optical interferometry and computed tomography (CT). Since the gas temperature is related to refractive index, once a series of two-dimensional (2D) phase modulation that is an integral of refractive index along an optical path is obtained, the 3D gas temperature distribution can be ideally determined in the same way as the widely-used CT to determine a distribution of attenuation factor. However, the series of 2D phase images is not complete; phase images from certain directions cannot be obtained because of limitations of the measurement system. Furthermore, the 2D images of phase modulation are not observed directly, since the interferometer can only detect a 2D image of intensity distribution called fringe pattern. To retrieve the phase modulation from the fringe pattern, both digital holography and phase unwrapping algorithm are applied. To obtain 3D gas temperature distributions with such incomplete data sets, we apply a method using localized compensator for phase unwrapping algorithm to obtain 2D modulation maps, and a maximum-likelihood tomography for a 3D reconstruction. Accuracy of each method is compared with that of conventional methods., 11047293

Phase unwrapping for noisy phase map using localized compensator
Tomioka, S., Nishiyama, S.
Applied Optics, 51, 21, 4984, 4994, OPTICAL SOC AMER, Jul. 2012, [Peer-reviewed], [Lead author]
English, Scientific journal, Phase unwrapping for a noisy image suffers from many singular points. Singularity-spreading methods are useful for the noisy image to regularize the singularity. However, the methods have a drawback of distorting phase distribution in a regular area that contains no singular points. When the singular points are confined in some local areas, the regular region is not distorted. This paper proposes a new phase unwrapping algorithm that uses a localized compensator obtained by clustering and by solving Poisson's equation for the localized areas. The numerical results demonstrate that the proposed method can improve the accuracy compared with other singularity-spreading methods. (C) 2012 Optical Society of America, 11047293

Phase unwrapping algorithm based on singularity compensation for three-dimensional shape measurement
Heshmat, S., Tomioka, S., Nishiyama, S.
Optical Review, 19, 6, 444, 450, OPTICAL SOC JAPAN, Nov. 2012, [Peer-reviewed], [Lead author]
English, Scientific journal, Three-dimensional (3D) imaging continues to attract much research interest for its wide applications. In 3D shape measurement, the phase carries information about the object. However, phase mapping is ambiguous as the extracted phase is returned in a form that suffers from 2 pi phase jumps. In this case, the phase data must be unwrapped to be fit for use. Furthermore, sometimes the presence of noise in the measured data, in which many singular points (SPs) are found, makes general phase unwrapping algorithms fail to produce accurate unwrapped results. For this reason, we propose a new phase unwrapping method for dynamic 3D shape measurement. The new algorithm is based on compensating the singularity of discontinuity sources. It uses direct compensators for adjoining SP pairs and uses rotational compensators for other SP pairs. The proposed algorithm has been evaluated and compared with past phase unwrapping methods. Results show that the proposed method gives satisfactory unwrapped results with a low computation time., 11047293

Reliable phase unwrapping algorithm based on rotational and direct compensators
Heshmat, S., Tomioka, S., Nishiyama, S.
Applied Optics, 50, 33, 6225, 6233, OPTICAL SOC AMER, Nov. 2011, [Peer-reviewed], [Corresponding author]
English, Scientific journal, Phase unwrapping still plays an important role in many data-processing chains based on phase information. Here, we introduce a new phase unwrapping approach for noisy wrapped phase maps of continuous objects to improve the accuracy and computational time requirements of phase unwrapping using a rotational compensator (RC) method. The proposed algorithm is based on compensating the singularity of discontinuity sources. It uses direct compensation for adjoining singular point (SP) pairs and uses RC for other SP pairs. The performance of the proposed method is tested through both simulated and real wrapped phase data. The proposed algorithm is faster than the original algorithm with the RC and has proved efficiency compared to other phase unwrapping methods. (C) 2011 Optical Society of America

Analysis of microstructural images of dry and water-saturated compacted bentonite samples observed with X-ray micro CT
Tomioka, Satoshi, Kozaki, Tamotsu, Takamatsu, Hidenori, Noda, Natsuko, Nisiyama, Shusuke, Kozai, Naofumi, Suzuki, Satoru, Sato, Seichi
Applied Clay Science, 47, 1-2, 65, 71, ELSEVIER SCIENCE BV, Jan. 2010, [Peer-reviewed], [Lead author]
English, Scientific journal, Compacted bentonite, of which the major clay mineral is montmorillonite, is a candidate buffer material for geological disposal of high-level radioactive waste. In this study, a microfocus X-ray computed tomography (micro-CT, X-ray microscope), which enables non-destructive, three-dimensional observation of the interior microstructure of a sample with high resolution (several microns), examined compacted montmorillonite samples under dry and water-saturated states. The images thus obtained were analyzed by a computer code developed for this study to obtain the information on the size and shape of montmorillonite grains in the samples before and after the water saturation. From the results of the image analysis, it can be supposed that the outer montmorillonite sheets of grains swelled and formed a gel, whereas the inner montmorillonite sheets did not change significantly in the water-saturation process. (C) 2008 Elsevier B.V. All rights reserved.

Phase unwrapping for noisy phase maps using rotational compensator with virtual singular points
Tomioka, Satoshi, Heshmat, Samia, Miyamoto, Naoki, Nishiyama, Shusuke
Applied Optics, 49, 25, 4735, 4745, OPTICAL SOC AMER, Sep. 2010, [Peer-reviewed], [Lead author]
English, Scientific journal, In the process of phase unwrapping for an image obtained by an interferometer or in-line holography, noisy image data may pose difficulties. Traditional phase unwrapping algorithms used to estimate a two-dimensional phase distribution include much estimation error, due to the effect of singular points. This paper introduces an accurate phase-unwrapping algorithm based on three techniques: a rotational compensator, unconstrained singular point positioning, and virtual singular points. The new algorithm can confine the effect of singularities to the local region around each singular point. The phase-unwrapped result demonstrates that accuracy is improved, compared with past methods based on the least-squares approach. (c) 2010 Optical Society of America

Analytical regularization of hypersingular integral for Helmholtz equation in boundary element method
Tomioka, Satoshi, Nishiyama, Shusuke
Engineering Analysis With Boundary Elements, 34, 4, 393, 404, ELSEVIER SCI LTD, Apr. 2010, [Peer-reviewed], [Lead author]
English, Scientific journal, This paper presents a gradient field representation using an analytical regularization of a hypersingular boundary integral equation for a two-dimensional time harmonic wave equation called the Helmholtz equation. The regularization is based on cancelation of the hypersingularity by considering properties of hypersingular elements that are adjacent to a singular node. Advantages to this regularization include applicability to evaluate cornet nodes, no limitation for element size, and reduced computational cost compared to other methods. To demonstrate capability and accuracy, regularization is estimated for a problem about plane wave propagation As a result. it is found that even at a corner node the most. significant error in the proposed method is due to truncation error of non-singular elements in discretization, and error from hypersingular elements is negligibly small. (C) 2009 Elsevier Ltd. All rights reserved.

Epithermal neutron tomography using compact electron linear accelerator
Kamiyama, T., Miyamoto, N., Tomioka, S., Kozaki, T.
Nuclear Instruments & Methods in Physics Research Section a-Accelerators Spectrometers Detectors and Associated Equipment, 605, 1-2, 91, 94, ELSEVIER SCIENCE BV, Jun. 2009, [Peer-reviewed]
English, Scientific journal, Neutron resonance absorption spectroscopy (N-RAS) with a pulsed neutron source can distinguish the dynamics of individual nuclides having resonance peaks on epithermal neutron region. The analyzed internal information of nuclide presence and its effective temperature can be reconstructed as distributions over the object cross-section using computed tomography (CT). Because some of the resonance absorption cross-sections have very large values, N-RAS could match the small neutron pulsed source by its high sensitivity. In this study, we have constructed a new instrument of N-RAS on a compact electron linac neutron source. Resonance absorption measurements and CT imaging with the instrument have succeeded for some kinds of nuclide. (C) 2009 Elsevier B.V. All rights reserved.

Three-Dimensional Wake Field Computations Based on Scattered-Field Time Domain Boundary Element Method
Fujita, Kazuhiro, Kawaguchi, Hideki, Weil, , Thomas, Tomioka, Satoshi
Ieee Transactions on Nuclear Science, 56, 4, 2341, 2350, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, Aug. 2009, [Peer-reviewed], [Corresponding author]
English, Scientific journal, We present time domain 3-D wake field calculations based on Scattered-field Time Domain Boundary Element Method (S-TDBEM), which is retarded Kirchhoff's boundary integral equations of scattered electromagnetic fields formulated on interior region problem and has no numerical dispersion in all spatial direction. We propose two main types of S-TDBEM schemes: full 3-D scheme for general 3-D geometries and a so-called 2.5-D scheme for transverse wake field calculation in axis-symmetric structures. Several numerical examples are demonstrated for typical accelerator structures: elliptical pillbox and the TESLA 9-cell cavities. The developed 3-D/2.5-D S-TDBEM codes are verified by comparison with the modal analysis and the finite integration technique (FIT) in the numerical examples. Finally, as one of the most meaningful applications of the S-TDBEM, we demonstrate wake field simulations of a curved trajectory bunch with the developed 3-D S-TDBEM code.

Quantitative epithermal neutron tomography with compact pulsed neutron source
Takashi Kamiyama, Naoki Miyamoto, Satoshi Tomioka, Tamotsu Kozaki
IEEE Nuclear Science Symposium Conference Record, 1266, 1270, 2009, [Peer-reviewed]
English, International conference proceedings, Neutron resonance absorption spectroscopy (N-RAS) with a pulsed neutron source can distinguish the dynamics of individual nuclides which have neutron resonance peaks on epithermal neutron region. Because some of the resonance absorption cross sections have very large values, N-RAS could match the small neutron pulse source by its high sensitivity. The analyzed spectra information of nuclide presence and its effective temperature can be reconstructed as distributions over the object cross-section using computer tomography (CT). In this study the projected nuclide densities were obtained from the resonance absorption equation fitting with the series of obtained spectra. Then, we reconstructed the quantitative nuclide density tomogram using the CT technique about them. ©2009 IEEE.

Quantitative Epithermal Neutron Tomography with Compact Pulsed Neutron Source
T. Kamiyama, N. Miyamoto, S. Tomioka, T. Kozaki
2009 IEEE NUCLEAR SCIENCE SYMPOSIUM CONFERENCE RECORD, VOLS 1-5, 1266, +, IEEE, 2009, [Peer-reviewed]
English, International conference proceedings, Neutron resonance absorption spectroscopy (N-RAS) with a pulsed neutron source can distinguish the dynamics of individual nuclides which have neutron resonance peaks on epithermal neutron region. Because some of the resonance absorption cross sections hale very large values, N-RAS could match the small neutron pulse source by its high sensitivity. The analyzed spectra information of nuclide presence and its effective temperature can he reconstructed as distributions over the object cross-section using computer tomography (CT). In this study the projected nuclide densities were obtained from the resonance absorption equation fitting with the series of obtained spectra. Then, we reconstructed the quantitative nuclide density tomogram using the CT technique about them.

Imaging and texture observation of materials by using a pulsed neutron spectroscopic transmission method
Kiyanagi, Yoshiaki, Kamiyama, Takashi, Takada, Osamu, Morita, Keigo, Iwase, Kenji, Suzuki, Shun, Furusaka, Michihiro, Hiraga, Fujio, Tomioka, Satoshi, Mishima, Kaichiro, Takenaka, Nobuyuki, Ino, Takashi
Nuclear Instruments & Methods in Physics Research Section a-Accelerators Spectrometers Detectors and Associated Equipment, 600, 1, 167, 169, Elsevier BV, 21 Feb. 2009, [Peer-reviewed]
Scientific journal

Time Domain Boundary Element Analysis of Wake Fields in Long Accelerator Structures
Fujita, Kazuhiro, Kawaguchi, Hideki, Hampel, Robert, Mueller, Wolfgang F. O., Weil, , Thomas, Tomioka, Satoshi
Ieee Transactions on Nuclear Science, 55, 5, 2584, 2591, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, Oct. 2008, [Peer-reviewed], [Corresponding author]
English, Scientific journal, We present an explicit Time Domain Boundary Element Method (TDBEM) scheme with moving window technique for short-range wake field simulations of long accelerator structures. The proposed scheme is formulated by Kirchhoff's boundary integral equation of the scattered electromagnetic field in interior region problems. Implementation of a moving window technique in the framework of TDBEM is achieved by taking into account the causality and the retardation properties of the boundary integral equation. A parallelization algorithm for this moving window implementation is also proposed. The proposed TDBEM code with the moving window technique is applied to several practical examples of long accelerator structures. Numerical results obtained with the TDBEM code are compared with those of several finite integration codes.

Moving Window技術を用いた時間領域境界要素法による粒子加速器航跡場の大規模並列計算　　　　　　　　　　　　　　　
藤田和広, 川口秀樹, 富岡智
信学技報, 107, 1, EMT2007-2, 7, 12, Aug. 2007
Japanese

Numerical reconstruction of an infrared wavefront utilizing an optical phase modulation device
Miyamoto, Naoki, Nisiyama, Shusuke, Tomioka, Satoshi, Enoto, Takeaki
Optics Communications, 272, 1, 67, 72, ELSEVIER SCIENCE BV, Apr. 2007, [Peer-reviewed]
English, Scientific journal, We utilize nitroanisole, that absorbs infrared (IR) radiation as heat, as an optical modulation device based on a thermal process. The nitroanisole exhibits a thermal lens effect, i.e. a temperature dependent refractive index. Hence, the nitroanisole can induce phase modulation to visible light, in direct response to intensity of the incident IR radiation. The proposed method can be used to obtain the phase modulation distribution that corresponds to the IR intensity distribution, i.e. the IR hologram itself, on the nitroanisole by examining the phase map of visible light that is modulated upon passing through the nitroanisole. The IR wavefront can be reconstructed by calculating extracted IR holograms through the Fresnel transform. It is verified that both the amplitude and the phase of the IR wavefront can be reconstructed accurately by proposed method. (c) 2006 Elsevier B.V. All rights reserved.

Explicit time domain boundary element scheme for dispersion-free wake field calculation of long accelerator structures
K. Fujita, R. Hampel, W. F. O. Mueller, T. Weiland, H. Kawaguchi, S. Tomioka, T. Enoto
2007 IEEE PARTICLE ACCELERATOR CONFERENCE, VOLS 1-11, 1549, +, IEEE, 2007, [Peer-reviewed]
English, International conference proceedings, This paper introduces a new explicit scheme with a moving window option for wake field calculation of long accelerator structures. This scheme is based on a time domain boundary element method (TDBEM) which uses a retarded Kirchhoff boundary integral equation for interior region problems. As a corollary of this boundary integral equation, our approach allows a conformal modeling of a structure and time domain wake field simulation without numerical grid dispersion errors in all spatial directions. The implementation of a moving window technique in the framework of TDBEM is presented and it is shown that this moving window technique allows to significantly reduce memory requirement of the TDBEM scheme in the short range wake field calculation. Several numerical examples are demonstrated for the TESLA 9-cell cavity and tapered collimators. The results of the new TDBEM scheme are compared with those of finite difference codes.

Scattered-field time domain boundary element method and its application to transient electromagnetic field simulation in particle accelerator physics
Fujita, Kazuhiro, Kawaguchi, Hideki, Nishiyama, Shusuke, Tomioka, Satoshi, Enoto, Takeaki, Zagorodnov, Igor, Weil, , Thomas
Ieice Transactions on Electronics, E90C, 2, 265, 274, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, Feb. 2007, [Peer-reviewed]
English, Scientific journal, Authors have been working in particle accelerator wake field analysis by using the Time Domain Boundary Element Method (TDBEM). A stable TDBEM scheme was presented and good agreements with conventional wake field analysis of the FDTD method were obtained. On the other hand, the TDBEM scheme still contains difficulty of initial value setting on interior region problems for infinitely long accelerator beam pipe. To avoid this initial value setting, we adopted a numerical model of beam pipes with finite length and wall thickness on open scattering problems. But the use of such finite beam pipe models causes another problem of unwanted scattering fields at the beam pipe edge, and leads to the involvement of interior resonant solutions. This paper presents a modified TDBEM scheme, Scattered-field Time Domain Boundary Element Method (S-TDBEM) to treat the infinitely long beam pipe on interior region problems. It is shown that the S-TDBEM is able to avoid the excitation of the edge scattering fields and the involvement of numerical instabilities caused by interior resonance, which occur in the conventional TDBEM.

Nonlinear least square regression by adaptive domain method with multiple genetic algorithms
Tomioka, Satoshi, Nisiyama, Shusuke, Enoto, Takeaki
Ieee Transactions on Evolutionary Computation, 11, 1, 1, 16, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, Feb. 2007, [Peer-reviewed], [Lead author]
English, Scientific journal, In conventional least square (LS) regressions for nonlinear problems, it is not easy to obtain analytical derivatives with respect to target parameters that comprise a set of normal equations. Even if the derivatives can be obtained analytically or numerically, one must take care to choose the correct initial values for the iterative procedure of solving an equation, because some undesired, locally optimized solutions may also satisfy the normal equation. In the application of genetic algorithms (GAs) for nonlinear LS, it is not necessary to use normal equations, and a GA is also capable of avoiding localized optima. However, convergence of population and reliability of solutions depends on the initial domain of parameters, similarly to the choice of initial values in the abovementioned method using the normal equation. To overcome this disadvantage of applying GAs for nonlinear LS, we propose to use an adaptive domain method (ADM) in which the parameter domain can change dynamically by using several real-coded GAs with short lifetimes.
Through an example problem, we demonstrate improvements in terms of both the convergence and the reliability by ADM. A further merit in the proposed method is that it does not require any specialized knowledge about GAs or their tuning. Therefore, the nonlinear LS by ADM with GAs are accessible to general scientists for various applications in many fields.

Application of the nitroanisole as an infrared detector used in middle infrared interferometer
N Miyamoto, S Nisiyama, S Tomioka, T Enoto
OPTICS COMMUNICATIONS, 260, 1, 25, 29, ELSEVIER SCIENCE BV, Apr. 2006, [Peer-reviewed]
English, Scientific journal, We propose the application of nitroanisole as a detector for middle infrared (mid-IR) interferometry or holography. The present experiment utilizes the liquid form of nitroanisole, which has a thermal lens effect. i.e. a temperature dependent refractive index. Since the nitroanisole absorbs IR radiation as heat, it is possible to estimate the IR intensity distribution on the nitroanisole from the diffraction pattern made by visible laser light that is transmitted through the nitroanisole. In this study, the time resolution and the diffraction efficiency of the nitroanisole was measured under various conditions. The experimental results show that the nitroanisole has a time resolution as high as that of a standard video camera, as well as a high diffraction efficiency and the spatial resolution equivalent to that of a conventional IR camera. Furthermore, we confirmed that the phase shift in mid-IR region can be estimated by analyzing the change in the visible diffraction pattern. (c) 2005 Elsevier B.V. All rights reserved.

Photoconductive properties of a new polyacetylene having a carbazole substituent　　　　　　　　　　　　　　　
Toshihiro Inoue, Taro Makigaki, Yasuteru Mawatari, Munehiro Kozuka, Takeaki Enoto, Satoshi Tomioka, Masayosi Tabata
Polymer Preprints, Japan, 54, 2, 4020, 2005
Japanese, International conference proceedings, We have prepared various substituted polyacetylenes using a Rh complex catalyst, [Rh(norbornadiene)Cl] 2. In this report we show photoconductive properties of the new polyacetylene having a carbazole substituent. The new polyacetylene which was doped by using iodine showed fairly high photo conductivity compared to the undoped polymer.

Infrared phase-shifting interferometry using the nitroanisole as a two-dimensional detector
Naoki Miyamoto, Shusuke Nisiyama, Satoshi Tomioka, Takeaki Enoto
Proceedings of SPIE - The International Society for Optical Engineering, 6049, 0O.01, 0O.10, 2005, [Peer-reviewed]
English, International conference proceedings, We propose the application of nitroanisole as a two-dimensional detector for infrared (IR) phase-shifting interferometry. The nitroanisole that is utilized in our experiment is liquid at room temperature and it has significant thermal lens effect, i.e. the refractive index for visible light is dependent on temperature. In addition, we verified by infrared absorption spectroscopy that the nitroanisole has an absorption band around 10.6μm in the IR region. Therefore, the interference fringe pattern that is generated on the nitroanisole by the IR beams may be treated as a phase grating for visible light. A Fresnel diffraction pattern made by visible laser light that is transmitted through the phase grating, i.e. the nitroanisole, can be observed as a superposition of the intensities corresponding to the profile of the phase grating and its harmonic components. Additionally, in response to a shift of the interference fringe on the nitroanisole, the Fresnel diffraction pattern on the observation plane also shifts by an equal amount. Utilizing this characteristic of nitroanisole, we attempted to estimate the IR phase map by applying the phase-shifting method to the diffraction patterns. We conducted an experiment aimed to measure the angle of a wedge of ZnSe, which is an IR transmitting material, and we confirmed the feasibility of obtaining phase measurements in the IR region by this procedure.

Identification of Electromagnetic Mode Excited by Electron Beam in Waveguide using Genetic Algorithm　　　　　　　　　　　　　　　
S. Tomioka, S. Nisiyama, T. Enoto
Computational Engineering I, --- Advances in Continuum Mechanics and Electro Magnetics ---, Japan Society for Computational Methods in Engineering, 251, 260, 2004, [Peer-reviewed]
English, Scientific journal

An improvement method of the simultaneity of image on ultra high-speed X-ray framing camera with the gated microchannel plate detector
Y Ito, Y Katoh, M Kagata, S Nisiyama, S Tomioka, T Enoto
25TH INTERNATIONAL CONGRESS ON HIGH-SPEED PHOTOGRAPHY AND PHOTONICS, 4948, 739, 744, SPIE-INT SOC OPTICAL ENGINEERING, 2003, [Peer-reviewed]
English, International conference proceedings, Ultra high-speed X-ray framing cameras have improved considerably in recent years. Frames with temporal resolution of less than 100 ps are achievable, due to application of the non-linear amplification properties a microchannel plate (MCP). However, in the case of frame resolution under 100 ps, the propagation delay of the shuttering pulse on the MCP poses a significant problem to the maintenance of simultaneity of gated images. In the present research, a method to augment the simultaneity of images is presented. In previous designs, the photocathode was coated onto the MCP input surface. The improved design presented here separates the photocathode from the MCP detector. The transit time of the photoelectrons is varied at each point on the gated electrode is with respect to the MCP detector. Results show that the simultaneity of images is improved with this new design.

A use of BEM and NN system to estimate density distribution of plasma
Atsushi Ota, Satoshi Tomioka, Shusuke Nisiyama, Takeaki Enoto
Inverse Problems in Engineering Mechanics IV, 389, 398, Elsevier Ltd., 2003, [Peer-reviewed]
English, In book, This chapter discusses an inverse analysis for the sake of a non-destructive estimation system for a measurement of an inhomogeneous distribution of plasma by scattering field. The inverse analysis is based on two techniques: (1) multi-layered Neural networks (NN) to solve inverse problem, and (2) a boundary element method to solve a direct problem to generate learning data for the NN. In the case of an analysis using simple technique, the learning procedure in NN did not have a good convergence. Hence, two techniques to improve the convergence are proposed: (1) the normalization technique for the input data with consideration of the distribution of amplitude of the input data, and (2) the dividing section technique. It is clarified that combination of these techniques provides a rapid convergence, and leads to the availability of the estimation system. © 2003 Elsevier B.V. All rights reserved.

相対論的電子ビーム断面形状推定のための並列遺伝的アルゴリズムによる逆問題解析　　　　　　　　　　　　　　　
富岡 智, 西山 修輔, 榎戸 武揚
計算数理工学論文集, 1, 33, 38, Jul. 2001, [Peer-reviewed]
Japanese, Scientific journal

The study of the spatial resolution improvement of the scanning detector
Y Katoh, Y Ito, N Tomonura, S Tomioka, T Enoto
24TH INTERNATIONAL CONGRESS ON HIGH-SPEED PHOTOGRAPHY AND PHOTONICS, 4183, 209, 216, SPIE-INT SOC OPTICAL ENGINEERING, 2001, [Peer-reviewed]
English, International conference proceedings, In the scanning detector we propose the new system for improving spatial resolution by making sensitivity distribution of a detecting element vary. This can be simply done by only adding the filter with sensitivity distribution in front of a detecting element without requiring the higher density of equipment. In our laboratory, the plasma electron density distribution measurement by the holographic interferometry in far-infrared region has been proceeded. As one of the infrared detection material, we chose HgCdTe, and it was used as a scanning detecting element. As a. verification of this system, we added the infrared filter in the front of HgCdTe, and measured the spatial resolution using a knife edge. For the method for calculating Modulation Transfer Function (MTF) from Edge Response Function (ERF), we also propose the new technique that we name the virtual test chart method. In this technique, we simulates the response corresponded to periodic bar patterns from ERF, and calculates the contrast ratio from this response. From the result of measurement that added the infrared ray filter, the validity of this system was shown. By the simulation and the experiment, the optimum sensitivity distribution was obtained in this system.

Scattered field FD-TD analysis for wake-fields computation
S Nisiyama, S Tomioka, T Enoto
INTERNATIONAL JOURNAL OF APPLIED ELECTROMAGNETICS AND MECHANICS, 14, 1-4, 243, 247, IOS PRESS, 2001, [Peer-reviewed]
English, Scientific journal, In this paper, a scattered field Finite-Difference Time-Domain (FD-TD) method is applied to wake-fields computation. In the ordinary FD-TD method or other methods based on the finite difference scheme, the trajectory of a traveling charged particle beam should be along the spatial grid. In the presented method, an arbitrary beam trajectory can be treated since the beam current is not placed on the spatial grid but is considered as an incident field source. Wake potentials of a simple system with a slightly angled beam trajectory are calculated for a demonstration.

The evaluation of an improvement method of the simultaneity of an ultra high-speed framing camera
Y Ito, Y Katoh, M Kagata, S Tomioka, T Enoto
24TH INTERNATIONAL CONGRESS ON HIGH-SPEED PHOTOGRAPHY AND PHOTONICS, 4183, 193, 200, SPIE-INT SOC OPTICAL ENGINEERING, 2001, [Peer-reviewed]
English, International conference proceedings, We propose a method to improve the shuttering characteristics of an ultra high-speed camera that consists of a proximity focused image intensifier (PFII) with an external transparent electrode (ETE). When the shuttering time of several tens of picoseconds is considered, the time delay by the propagation of the shuttering pulse can not be disregarded, and this time delay causes the problems in the system's simultaneity. First, the time of which the image was recorded is different by the place. Second, the time in which the photoelectron reaches the micro channel plate (MCP) input surface is different. For our research, the second problem mentioned above poses an obstacle. To utilize the nonlinear operation of the MCP for smaller gating time, it is necessary that each electron reaches the MCP in same time. Our proposal is to compensate for this second problem by controlling the electric field between the photocathode and the MCP. This is achieved by optimizing the shape of the electrode of the ETE. We show that the variance of arrival time is reduce from 30ps to 5ps using numerical analysis by FDTD method.

Simulation in applying genetic algorithm for non-destructive measurement of electron beam transverse profile
S Tomioka, S Nisiyama, T Enoto
INTERNATIONAL JOURNAL OF APPLIED ELECTROMAGNETICS AND MECHANICS, 14, 1-4, 215, 219, IOS PRESS, 2001, [Peer-reviewed]
English, Scientific journal, For the purpose of non-destructive measurement of the cross-sectional shape of an electron beam, we have studied a detection system that is composed of both a number of antennas and a current monitor. The antenna detects an electric field, and the current monitor detects an integral of beam currents.
The signals acquired from these detectors are applied as the input of an inverse problem. We adopt the genetic algorithm to simulate the profile measurement as an inverse problem analysis.
The results showed that this detection system is partially effective, even though this system is an "ill-posed problem" (i.e. the number of input data parameters is less than the number of parameters to be estimated). We also found that the current monitor, which cannot acquire position-dependent information, is nevertheless useful to accelerate the convergence of sub-optimal beam profiles.

FD-TD analysis of scattered fields excited by a high energy pulsed beam of charged particles using point charge responses
S Nisiyama, S Tomioka, T Enoto
IEEE TRANSACTIONS ON MAGNETICS, 36, 4, 888, 891, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, Jul. 2000
English, Scientific journal, In this paper, me show a finite-difference time-domain (FD-TD) analysis of scattered fields excited by a pulsed beam using point charge responses and convolution. The advantages of this approach are easy handling of arbitrary beam trajectories and waveforms; efficient absorption for excited fields on open boundaries; and small amount of incident field calculation, In addition, we describe the relation between the temporal resolution and the allowable aliasing error since the point charge held as an incident field has very high frequency spectrum.

Dual Holographic Interferometry using Nitrobenzene as FIR Phase Detector　　　　　　　　　　　　　　　
Yoshinori Tsuji, Takeshi Harayama, Keiichi Nomura, Satoshi Tomioka, Takeaki Enoto
Proc. for Symposium on Advanced Research of Energy Technology 2000, 251, 258, Mar. 2000
Japanese

Analysis for Improvement of Simultaneity of Shuttering in an Ultra High-Speed Framing Camera
Y. Ito, Y. Katoh, M. Kagata, S. Tomioka, T. Enoto
IEEE Transactions on Magnetics, 36, 4, 1769, 1773, 2000, [Peer-reviewed]
English, Scientific journal, We suggest a method to improve the shuttering characteristics of an ultra high-speed camera that consists of a proximity focused image intensifier with a micro channel plate (MCP) and an external transparent electrode (ETE). Over a range of the gating times of the several tens of picoseconds, using this apparatus, there are two obstacles to the system's simultaneity, i.e., accuracy of photographing phenomena. First, the time required for the shuttering pulse to propagate on the electrode creates a time delay between different areas of the image photons passing through the ETE. Second, the photoelectrons do not reach the MCP simultaneously. If we attempt to speed-up the gating time using nonlinear operation of the MCP, the latter problem has an undesirable effect on the resulting image. Our proposal is to compensate for the latter problem and improve the simultaneity of the arrival time of photoelectrons at the MCP input surface by controlling the electric field between the photocathode and the MCP. This is achieved by optimizing the shape of the electrode. Further analysis by FDTD and an electron trajectory tracking method verified that the variance of arrival time is reduced from 30 ps to 5 ps with the altered electrode shape. © 2000 IEEE.

Improvement of Temporal Characteristics of Ultra High Speed Framing Camera for Measurement of LINAC Electron Beam　　　　　　　　　　　　　　　
Yoshihiro Ito, Nobuhisa Tonomura, Yasuto Katoh, Makoto Kagata, Satoshi Tomioka, Takeaki Enoto
Proc. of the 24th Linear Accelerator Meeting in Japan, 401, 403, Jul. 1999
Japanese

A novel boundary element method for nonuniform neutron diffusion problems
M Itagaki, S Nisiyama, S Tomioka, T Enoto
JOURNAL OF NUCLEAR SCIENCE AND TECHNOLOGY, 36, 3, 273, 281, TAYLOR & FRANCIS LTD, Mar. 1999, [Peer-reviewed]
English, Scientific journal, An advanced boundary element formulation has been proposed to solve the neutron diffusion equation (NDE) for a 'nonuniform' system. The continuous spatial distribution of a nuclear constant is assumed to he described using a polynomial function, Part of the constant term in the polynomial is left on the left-hand-side of the NDE, while the remainding is added to the fission source term on the right,hand-side to create a fictitious source. When the neutron flux is also expanded using a polynomial, the boundary integral equation corresponding to the NDE contains a domain integral related to the polynomial source. This domain integral is transformed into an infinite series of boundary integrals, by repeated application of the particular solution for a Poisson-type equation with the polynomial source. In two-dimensional, one-group test calculations for rectangular domains, the orthogonality of Legendre polynomials was used to determine the polynomial expansion coefficients. The results show good agreement with those obtained from finite difference computations in which the nonuniformity was approximated by a large number of material regions.

ニトロベンゼンを赤外線の位相情報検出材料として用いた２段ホログラフィー干渉法　　　　　　　　　　　　　　　
榎戸 武揚, 富岡 智, 原山 武志, 森部 英征
機能材料, 19, 3, 39, 47, Feb. 1999, [Peer-reviewed]
Japanese, Scientific journal

Internal Field Error Reduction in Boundary Element Analysis for Helmholtz Equation
Satoshi Tomioka, Shusuke Nisiyama, Masafumi Itagaki, Takeaki Enoto
Engineering Analysis with Boundary Elements, 23, 3, 211, 222, Jan. 1999, [Peer-reviewed]
English, Scientific journal

A Harmonics Selective Slot Antenna for Beam Position Monitor　　　　　　　　　　　　　　　
Shusuke Nisiyama, Kenta Itoh, Hiroyasu Itoh, Satoshi Tomioka, Takeaki Enoto
Proc. of the 23rd Linear Accelerator Meeting in Japan, 181, 183, Sep. 1998
Japanese

定在波測定を用いる電子ビーム微細構造パルス幅の計測　　　　　　　　　　　　　　　
伊藤 裕康, 加賀田 誠, 西山 修輔, 富岡 智, 榎戸 武揚
プラズマ・核融合学会誌, 74, 1, 29, 37, Jan. 1998, [Peer-reviewed]
Japanese, Scientific journal

A New Estimate Method of Micro-pulse Width Using Standing Wave Measurement.　　　　　　　　　　　　　　　
H. Itoh, S. Nisiyama, N. Ishii, S. Tomioka, T. Enoto
Proc. 11th Symp. on Accelerator Science and Technology, 415, 417, Oct. 1997
English

Power iterative multiple reciprocity boundary element method for solving three-dimensional Helmholtz eigenvalue problems
M Itagaki, S Nishiyama, S Tomioka, T Enoto, N Sahashi
ENGINEERING ANALYSIS WITH BOUNDARY ELEMENTS, 20, 2, 113, 121, ELSEVIER SCI LTD, Sep. 1997, [Peer-reviewed]
English, Scientific journal, The multiple reciprocity boundary element method (MRBEM) has been employed to solve the three-dimensional Helmholtz equation, del(2) phi + k(2) phi = 0. In the present technique, the Helmholtz equation is arranged as del(2) phi + k(0)(2) phi + phi/lambda = 0, where k(0) is an estimate of k and lambda is equal to (k(2) - k(0)(2))(-1). As the term phi/lambda is treated as a source, the power iteration technique with Wielandt's spectral shift is used to find the value of X. The boundary integral equation is formulated with the fundamental solution to del(2) phi + k(0)(2) phi + delta(i) = 0. The domain integral related to the above source is transformed into a series of boundary integrals, with the aid of the higher order fundamental solutions based on the spherical Bessel functions. The eigenvalue k(2) can also be described using only boundary integrals. Test calculations demonstrate that the present technique is efficient for finding k(2) and easier to handle than the conventional determinant search scheme. (C) 1997 Elsevier Science Ltd.

Matrix-type higher order fundamental solutions to three-dimensional two-group neutron diffusion equations
M Itagaki, S Tomioka, S Nisiyama, T Enoto
ENGINEERING ANALYSIS WITH BOUNDARY ELEMENTS, 20, 1, 63, 71, ELSEVIER SCI LTD, Jul. 1997, [Peer-reviewed]
English, Scientific journal, The zero-order and the higher-order fundamental solutions for the 3-D two-group neutron diffusion equations have been derived in such a way that these solutions satisfy the first and the second group equations simultaneously. Each degree of the solutions has a 2 x 2 matrix form based on two types of function, r(p) exp(-iBr) and r(p) exp(-kr). Singularities of type (1/r) are only found at the diagonal components of the zero-order solutions; however, no singularities are found at any components of the higher-order solutions. These solutions can be used for applying the multiple reciprocity boundary element method to 3-D two-group neutron diffusion problems. (C) 1997 Elsevier Science Ltd.

FD-TD法による超高速カメラのシャッタリング特性の解析
加賀田 誠, 富岡 智, 榎戸 武揚
電気学会論文誌, 117-A, 1, 22, 28, Jan. 1997, [Peer-reviewed]
Japanese, Scientific journal

電子ビームによって形成される電磁界のスペクトル解析(II)　　　　　　　　　　　　　　　
伊藤 裕康, 西山 修輔, 石田 崇, 富岡 智, 榎戸 武揚
Proc. of the 21st Linear Accelerator Meeting in Japan, 340, 342, Sep. 1996
Japanese

A new formulation of boundary element method for a thin metal plate in the electrostatic potential problem
S Nisiyama, S Tomioka, M Kagata, H Itoh, T Enoto
BOUNDARY ELEMENT METHODS, 319, 326, ELSEVIER SCIENCE PUBL B V, 1996
English, International conference proceedings

電磁界問題の境界要素法における薄い金属板に関する一考察　　　　　　　　　　　　　　　
西山 修輔, 富岡 智, 加賀田 誠, 伊藤 裕康, 榎戸 武揚
境界要素法論文集, 12, 23, 26, Dec. 1995, [Peer-reviewed]
Japanese, Scientific journal

不均質媒質中のヘルムホルツ波動方程式への境界要素法の適用
富岡 智, 加賀田 誠, 伊藤 裕康, 西山 修輔, 榎戸 武揚
電気学会論文誌A, 115, 11, 1098, 1104, Nov. 1995, [Peer-reviewed]
Japanese, Scientific journal

ビーム近傍におけるスロットアンテナの数値解析　　　　　　　　　　　　　　　
西山 修輔, 伊藤 裕康, 富岡 智, 榎戸 武揚
Proceedings of the 20th Linear Accelerator Meeting in Japan, 248, 250, Sep. 1995
Japanese

境界要素法における二次元波動方程式の解の安定性について　　　　　　　　　　　　　　　
富岡 智, 西山 修輔, 加賀田 誠, 伊藤 裕康, 榎戸 武揚
境界要素法研究会 第45回例会, 1, 23, Mar. 1995
Japanese

二次元過渡応答境界要素法における解の安定性
富岡 智, 加賀田 誠, 伊藤 裕康, 榎戸 武揚
電気学会論文誌A, 115, 1, 9, 16, Jan. 1995, [Peer-reviewed]
Japanese, Scientific journal

境界要素法による不均質な波数を有するヘルムホルツ方程式の近似解法　　　　　　　　　　　　　　　
富岡 智, 加賀田 誠, 伊藤 裕康, 榎戸 武揚
境界要素法論文集, 11, 83, 88, Dec. 1994, [Peer-reviewed]
Japanese, Symposium

Stability of Solutions in 2-Dimensional Transient Boundary Element Method Analysis
TOMIOKA Satoshi, KAGATA Makoto, ITOH Hiroyasu, ENOTO Takeaki
The Transactions of the Institute of Electrical Engineers of Japan. A, 115, 1, 9, 16, 電気学会, Dec. 1994, [Peer-reviewed]
Japanese

Spectrum Analysis of an Electromagnetic Field Generated by LINAC Electron Beams　　　　　　　　　　　　　　　
Hiroyasu Itoh, Shusuke Nisiyama, Satoshi Tomioka, Takeaki Enoto
Proceedings of the 1994 International Linac Conference, 860, 862, Aug. 1994
English

スロットアンテナを用いた電子ライナックのビーム位置モニタ　　　　　　　　　　　　　　　
西山 修輔, 伊藤 裕康, 富岡 智, 榎戸 武揚
Proceedings of the 19th Linear Accelerator Meeting in Japan(JAERI-Conf 94-03), 254, 256, Jul. 1994
Japanese

An experimental and analytical study of high speed shuttering characteristics of proximity focused image intensifiers　　　　　　　　　　　　　　　
B. D. Landberg, M. Kagata, S.Tomioka, T. Enoto, I. Fukai
Int. J. of Applied Electromagnetics in Materials, 5, 377, 380, Jan. 1994, [Peer-reviewed]
English, Scientific journal

Numerical analysis of ultra high-speed shuttering characteristics using finite-difference time-domain method　　　　　　　　　　　　　　　
M. Kagata, B. D. Landberg, S.Tomioka, T. Enoto, I. Fukai
Int. J. of Applied Electromagnetics in Materials, 5, 381, 384, Jan. 1994, [Peer-reviewed]
English, Scientific journal

Removing spurious solutions in boundary elemental method for multimedia problems using virtual boundary dividing method　　　　　　　　　　　　　　　
S.Tomioka, T. Enoto, I. Fukai
Int. J. of Applied Electromagnetics in Materials, 5, 357, 360, Jan. 1994, [Peer-reviewed]
English, Scientific journal

異なる媒質を含むファブリ・ペロー共振器の境界要素法におけるスプリアス解除去
富岡 智, 榎戸 武揚
電気学会論文誌A, 113, 8, 572, 579, 電気学会, Aug. 1993, [Peer-reviewed]
Japanese, Scientific journal

電子ビームにより円筒導波管内に形成される電磁界の周波数解析　　　　　　　　　　　　　　　
伊藤裕康, 富岡智, 榎戸武揚
Proceedings of the 18th Linear Accelerator Meeting in Japan, 288, 291, Jul. 1993
Japanese

スロットアンテナによる電子ビーム測定とその過渡解析　　　　　　　　　　　　　　　
伊藤 裕康, 富岡 智, 榎戸 武揚
Proc. on 17th Linear Accelerator Meeting in Japan, 207, 209, Sep. 1992
Japanese

スロットアンテナを用いた電子ビーム周囲電界の測定　　　　　　　　　　　　　　　
伊藤裕康, 三浦広土, 富岡智, 榎戸武揚
電気関係学会北海道支部連合大会, 426, 427, Oct. 1991
Japanese

スロットアレイアンテナを用いた電子ビーム周囲電界測定　　　　　　　　　　　　　　　
三浦 広土, 富岡 智, 伊藤 裕康, 榎戸 武揚
Proc. of the 16th Linear Accelerator Meeting in Japan, 263, 265, Sep. 1991
Japanese

プラズマを含むファブリ・ペロー共振器の領域分割型境界要素法による解析　　　　　　　　　　　　　　　
富岡 智, 榎戸 武揚, 深井 一郎
電気学会 電磁気理論研究会, EMT-87-12, 43, 52, Apr. 1987
Japanese

Training convolutional neural network using experimental data in phase extraction for 3D refractive-index measurement
貫洞大地, 柳瀬佳亮, 富岡智, 宮本直樹, 上田亮介, HESHMAT Samia, Optics & Photonics Japan講演予稿集(CD-ROM), 2019, 2019

3P4-11 Sonoluminescence observed in a generator of standing acoustic cavitation with the help of a punching metal plate(Poster Session)
Sasaki Koichi, Iwata Yushi, Nishiyama Shusuke, Tomioka Satoshi, Takada Noriharu, Proceedings of Symposium on Ultrasonic Electronics, 35, 477, 478, 03 Dec. 2014
Steering committee of symposium on ultrasonic electronics, English

3P4-25 Generation mechanism of standing acoustic cavitation with the help of a punching metal plate(Poster Session)
Sasaki Koichi, Iwata Yushi, Nishiyama Shusuke, Tomioka Satoshi, Takada Noriharu, Proceedings of Symposium on Ultrasonic Electronics, 34, 479, 480, 20 Nov. 2013
Steering committee of symposium on ultrasonic electronics, English

3Pa4-4 Development of an efficient method for producing standing cavitation bubbles(Poster Session)
Sasaki Koichi, Iwata Yushi, Nishiyama Shusuke, Tomioka Satoshi, Takada Noriharu, Proceedings of Symposium on Ultrasonic Electronics, 33, 361, 362, 13 Nov. 2012
Steering committee of symposium on ultrasonic electronics, English

金属メッシュの挿入によるソノプラズマの効率的生成
岩田悠史, 西山修輔, 富岡智, 高田昇治, 佐々木浩一, 応用物理学会学術講演会講演予稿集(CD-ROM), 73rd, ROMBUNNO.12A-E3-7, 27 Aug. 2012
Japanese

Angular distribution measurement of OTR on uneven metal surface　　　　　　　　　　　　　　　
Shusuke Nishiyama, Nobuyuki Miyamoto, Satoshi Tomioka, Tomoaki Hino, Proc. of the 5th Annual Meeting of Particle Accelerator Society of Japan and the 33rd Linear Accelerator Meeting in Japan, 806, 808, Aug. 2008
Japanese, Summary national conference

小型加速器中性子源を用いた中性子共鳴吸収断層撮像
加美山隆, 宮本直樹, 富岡智, 小崎完, 日本原子力学会秋の大会予稿集(CD-ROM), 2008, 2008

X-Ray Micro-CT Observation of Barrier Materials for Geological Disposal of High-Level Radioactive Waste
Koike Ryutaro, Kozaki Tamotsu, Takamatsu Hidenori, Noda Natsuko, Kitaichi Masatoshi, Tomioka Satoshi, Nisiyama Shusuke, Sato Seichi, Journal of the Visualization Society of Japan, 28, 2, 1125, 1125, 2008
The Visualization Society of Japan, Japanese

Analysis of X-ray Micro-CT Images Observed with Compacted Bentonite
TOMIOKA Satoshi, NISlYAMA Shusuke, KOZAKI Tamotsu, SATO Seichi, Journal of the Visualization Society of Japan, 28, 2, 1127, 1127, 2008
The Visualization Society of Japan, Japanese

小型加速器を利用した中性子共鳴吸収CTによる核種分布の非破壊分析
宮本直樹, 小崎完, 富岡智, 加美山隆, 日本非破壊検査協会大会講演概要集, 2007, 335, 338, 18 Oct. 2007
Japanese

P20 圧縮ベントナイト内部微細構造観察へのX線マイクロCT法の適用およびその最適化
高松 英則, 野田 菜摘子, 小崎 完, 北市 雅敏, 富岡 智, 佐藤 正知, 粘土科学討論会講演要旨集, 51, 186, 187, 12 Sep. 2007
日本粘土学会, Japanese

中性子共鳴吸収分光法と計算機断層撮像法を利用した核種分布の非破壊分析
宮本直樹, 小崎完, 富岡智, 加美山隆, 日本原子力学会秋の大会予稿集(CD-ROM), 2007, 0, C51, 171, 07 Sep. 2007
中性子共鳴吸収分光法と計算機断層撮像法を組み合わせることにより、非破壊で核種分布を断層撮影することが可能な分析法の開発を目的としている。複数の核種の存在分布、およびその密度分布を再構成できることを示した。, 一般社団法人 日本原子力学会, Japanese

Large-scale Parallel Computation of Particle Accelerator Wake Fields based on Time Domain Boundary Element Method with Moving Window Technique
FUJITA Kazuhiro, KAWAGUCHI Hideki, TOMIOKA Satoshi, Technical report of IEICE. OPE, 107, 173, 7, 12, 26 Jul. 2007
In order to compute wake fields, which are transient electromagnetic fields excited by a relativistic charged particle beam passing through a particle accelerator, the authors have been working in the development of time domain boundary element methods (TDBEM) as one of possibilities for the wake field analysis. In this paper, a TDBEM code with the moving window technique, which is used to save required memory, is parallelized to reduce the calculation time, and the code is applied to large-scale wake field analyses of practical long accelerator structures such as multi-cell cavities., 一般社団法人電子情報通信学会, Japanese

小型加速器中性子源への中性子共鳴吸収分光器の設置
加美山隆, 富岡智, 小崎完, 日本原子力学会春の年会要旨集(CD-ROM), 2007, 2007

Observation of microstructure of compacted bentonite by X-ray micro CT method optimized with computer simulation
Takamatsu Hidenori, Kozaki Tamotsu, Kitaichi Masatoshi, Tomioka Satoshi, Sato Seichi, Proceedings of Annual / Fall Meetings of Atomic Energy Society of Japan, 2006, 0, 750, 750, 2006
高レベル放射性廃棄物の地層処分において緩衝材として用いられる圧縮ベントナイトの内部微細構造は、そこでの放射性核種の移行と密接な関係があるとされる。本研究では、X線マイクロCT法により、ベントナイト内部微細構造の非破壊観察を行った。その際、予め3次元モンテカルロ計算コード（EGS4）を用いてX線透過シミュレーションを行い、その結果得られた観察の最適条件をCT実験に利用した。, Atomic Energy Society of Japan

Scattered-field Time-domain Boundary Element Method and its Applications to Numerical Analysis of Wake Fields in Particle Accelerators
FUJITA Kazuhiro, KAWAGUCHI Hideki, NISHIYAMA Shusuke, TOMIOKA Satoshi, ENOTO Takeaki, 電気学会研究会資料. : The Papers of Technical Meeting on Electromagnetic Theory, IEE Japan. EMT, 電磁界理論研究会, 2005, 61, 25, 30, 17 Nov. 2005
Japanese

10 Edification of Intellectual Curiosity through Simple Experiments for First Year Students
TOMIOKA Satoshi, NISIYAMA Shusuke, KITAGAWA Hiroki, ENOTO Takeaki, 工学・工業教育研究講演会講演論文集, 15, 0, 29, 30, 04 Sep. 2003
Japanese Society for Engineering Education, Japanese

スロットアンテナを用いた平面状ビーム位置モニタ　　　　　　　　　　　　　　　
西山 修輔, 富岡 智, 榎戸 武揚, Proc. of the 28th Linear Accelerator Meeting in Japan, 425, 427, Jul. 2003
Japanese, Summary national conference

X線マイクロCTによる圧縮ベントナイト内部微細構造の観察
小崎完, 富岡智, LIU J, 榎戸武揚, 佐藤正知, 香西直文, 鈴木覚, 日本原子力学会秋の大会予稿集, 2002, 2002

スロットアンテナとラットレースリングを用いた電子ビーム測定技術の研究　　　　　　　　　　　　　　　
株本 裕史, 西山 修輔, 富岡 智, 榎戸 武揚, Proc. of the 26th Linear Accelerator Meeting in Japan, 264, 266, Aug. 2001
Japanese, Summary national conference

Estimation of the Waveform of fine strucure pulse with Resonator　　　　　　　　　　　　　　　
Takashi Miyashita, Yoshiki Goto, Satoshi Tomioka, Takeaki Enoto, Proc. of the 25th Linear Accelerator Meeting in Japan, 377, 379, Jul. 2000
Japanese, Summary national conference

30pA11P Real-time Dual Holographic Interferometry in Infrared Region
逵 由典, 野村 啓一, 村上 純一, 富岡 智, 榎戸 武揚, プラズマ・核融合学会年会予稿集, 17, 214, 214, 2000
プラズマ・核融合学会, Japanese

エッセンス電気・電子回路　　　　　　　　　　　　　　　
佐々木 浩一, 富岡 智
共立出版, Nov. 2013, [Joint work]

屈折率の三次元分布計測法　　　　　　　　　　　　　　　
富岡 智
先進電磁波イメージング研究会, Feb. 2019, Japanese, Invited oral presentation
[Invited], [Domestic Conference]

Phase extraction from interferogram using machine learning　　　　　　　　　　　　　　　
Daichi Kando, Satoshi Tomioka
2019 IS&T International Symposium on Electronic Imaging, Jan. 2019, English, Oral presentation
[International presentation]

Direct Flux Method to Solve Flux Distribution of Two-dimensional Poisson's Equation　　　　　　　　　　　　　　　
Arata Hirokami, Satoshi Tomioka
The 37th JSST Annual International Conference on Simulation Technology, Sep. 2018, English, Oral presentation
[International presentation]

Real-time volumetric image generation with CT image deformation driven by displacement of internal fiducial markers　　　　　　　　　　　　　　　
Naoki Miyamoto, Naoki Matsumoto, Ryusuke Suzuki, Seishin Takao, Taeko Matsuura, Takaaki Fujii, Shusuke Hirayama, Satoshi Tomioka, Shinichi Shimizu, Kikuo Umegaki, Hiroki Shirato
2018 AAPM Annual Meeting, 2018, English, Oral presentation
[International presentation]

重みつきコンピュータトモグラフィーの過渡現象への応用　　　　　　　　　　　　　　　
富岡 智
画像計測研究会２０１７, 21 Sep. 2017, Japanese, Oral presentation
[Domestic Conference]

磁場のソレノイダル条件を満たす実座標線形MHDシミュレーション　　　　　　　　　　　　　　　
高堂渉, 松本裕, 渡邊清政, 富岡智, 及川俊一
日本原子力学会年会, 13 Sep. 2017, Japanese, Oral presentation
[Domestic Conference]

摂動磁場のソレノイダル条件の破綻がLHDのMHDシミュレーションに与える影響　　　　　　　　　　　　　　　
高堂渉, 松本裕, 渡邊清政, 富岡智, 及川俊一
日本物理学会秋期大会, 12 Sep. 2017, Japanese, Oral presentation
[Domestic Conference]

Resonance Mode Analysis of Cavity-ringdown Spectroscopy Including Inhomogeneous Medium Using Modified Fundamental Solution　　　　　　　　　　　　　　　
Kazutoshi Matsubara, Satoshi Tomioka, Koichi Sasaki
プラズマプロセッシング研究会・プラズマ材料科学シンポジウム, 16 Jan. 2017, Japanese, Poster presentation
[Domestic Conference]

キャリア成分を含む干渉縞の位相変調部判別法, 応用物理学会秋期学術講演会　　　　　　　　　　　　　　　
貫洞大地, 富岡智
応用物理学会秋期学術講演会, 16 Sep. 2016, Japanese, Oral presentation
[Domestic Conference]

Improvement of efficiency in patient setup and gated-irradiation for real-time tumor-tracking radiotherapy by resipratory phase segmentation algorithm based on the analysis of 3D trajectory of internal fiducial marker　　　　　　　　　　　　　　　
宮本直樹, 鈴木隆介, 高尾聖心, 松浦妙子, 松崎有華, 藤井孝明, 富岡智, 清水伸一, 梅垣菊男, 白土博樹
日本医学物理学会学術大会, 10 Sep. 2016, Japanese, Oral presentation
[Domestic Conference]

Weighted tomographic reconstruction for time varying object　　　　　　　　　　　　　　　
富岡智, 内藤大基, 西山修輔, 宮本直樹, 梅垣菊男
日本医学物理学会学術大会, 09 Sep. 2016, Japanese, Oral presentation
[Domestic Conference]

逐次近似型コンピュータトモグラフィー再構成法における雑音の影響　　　　　　　　　　　　　　　
富岡 智
画像計測研究会２０１５, 08 Jan. 2016, Japanese, Oral presentation
[Domestic Conference]

Effect of Re-Entering Particle on NBI Heating in Heliotron J　　　　　　　　　　　　　　　
岩淵征, 松本裕, 小林進二, 關良輔, 及川俊一, 富岡智
プラズマ・核融合学会年会, 24 Nov. 2015, Japanese, Oral presentation
[Domestic Conference]

Introduction of 3D Neutral Density Model to Heating Efficiency and. Distribution Function Analysis of High Energy Ions produced by NBI in LHD　　　　　　　　　　　　　　　
青木慎一郎, 松本裕, 關良輔, 河村学思, 横山雅之, 神尾修治, 長壁正樹, 及川俊一, 富岡智
プラズマ・核融合学会年会, 24 Nov. 2015, Japanese, Oral presentation
[Domestic Conference]

キャリア成分を含む干渉縞からの2次元位相変調分布の抽出
HASHIMOTO YASUHIRO, TOMIOKA SATOSHI, NISHIYAMA SHUSUKE, SASAKI KOICHI
応用物理学会北海道支部・日本光学会北海道地区合同学術講演会講演予稿集, 09 Jan. 2015, Japanese

Electron Density Measurement of Argon Containing Plasmas by Saturation Spectroscopy　　　　　　　　　　　　　　　
S. Nishiyama, H. Wang, S. Tomioka, K. Sasaki
67th Annual Gaseous Electronics Conference, Nov. 2014, English, Oral presentation
[International presentation]

Mechanism of efficient generation of cavitation bubbles in a sonoplasma production system assisted by a punching metal plate: effect of power deposition　　　　　　　　　　　　　　　
Y. Iwata, S. Nishiyama, S. Tomioka, N. Takada, K. Sasaki
8th International Conference on Reactive Plasmas, 2014, English, Oral presentation

3P4-25 Generation mechanism of standing acoustic cavitation with the help of a punching metal plate(Poster Session)
Sasaki Koichi, Iwata Yushi, Nishiyama Shusuke, Tomioka Satoshi, Takada Noriharu
Proceedings of Symposium on Ultrasonic Electronics, 20 Nov. 2013, English

Performance Evaluation of Phase Unwrapping Algorithms for Noisy Measurements
Samia Heshmat, Satoshi Tomioka, Shusuke Nishiyama
FRINGE 2013 - 7th International Workshop on Advanced Optical Imaging and Metrology, Sep. 2013, English, Oral presentation

不完全データによる光音響イメージングにおける音源分布推定の精度評価　　　　　　　　　　　　　　　
及川 裕, 富岡 智
第62回理論応用力学講演会, Mar. 2013, Oral presentation

Effect of mirror size in the measurement of OH density by cavity-ringdown absorption spectroscopy in plasma-enhanced premixed burner flame　　　　　　　　　　　　　　　
K. Zaima, S. Tomioka, K. Sasaki
16th International Symposium on Laser-Aided Plasma Diagnostics, 2013, English, Oral presentation

Mechanism of efficient production of standing sonoplasmas with the help of a punching metal plate　　　　　　　　　　　　　　　
K. Sasaki, Y. Iwata, S. Tomioka, S. Nishiyama, N. Takada
66th Annual Gaseous Electronics Conference, 2013, Oral presentation

レーザー照射を利用した材料表面周期パターン創製　　　　　　　　　　　　　　　
細川雄亮, 赤松義哲, 石岡準也, 谷津茂男, 渡辺精一, 富岡智
プラズマ・核融合学会第30回年会, 2013, Oral presentation

拡張ウィンドウを用いたバックグラウンドフリンジを含む干渉縞のキャリア 周波数評価　　　　　　　　　　　　　　　
橋本康弘, 富岡智, 西山修輔, 佐々木浩一
2013年応用物理学会秋季学術講演会, 2013, Oral presentation

パンチングメタルを有するソノプラズマ生成装置におけるシャドウグラフイメージング　　　　　　　　　　　　　　　
岩田 悠史, 西山 修輔, 富岡 智, 高田 昇治, 佐々木 浩一
第30回プラズマプロセシング研究会, 2013, Oral presentation

光音響CTにおける音源分布推定の精度評価　　　　　　　　　　　　　　　
及川 裕, 富岡 智
画像計測研究会２０１３, 2013, Oral presentation

3Pa4-4 Development of an efficient method for producing standing cavitation bubbles(Poster Session)
Sasaki Koichi, Iwata Yushi, Nishiyama Shusuke, Tomioka Satoshi, Takada Noriharu
Proceedings of Symposium on Ultrasonic Electronics, 13 Nov. 2012, English

Investigation of phase unwrapping process for laser induced plasma interferometry　　　　　　　　　　　　　　　
Samia Heshmat, Satoshi Tomioka, Shusuke Nishiyama
7th International Conference on Laser Induced Breakdown Spectroscopy, Sep. 2012, English, Oral presentation

Phase Unwrapping Algorithm Based on Compensation for 3D Shape Measurement　　　　　　　　　　　　　　　
Samia Heshmat, Satoshi Tomioka, Shusuke Nishiyama
The 1st International Laser Display Conference, Apr. 2012, English, Oral presentation

位相トモグラフィーによる非接触三次元気体温度分布計測　　　　　　　　　　　　　　　
富岡 智
核融合科学研究所画像計測研究会, Sep. 2011, Japanese, Oral presentation

放射化二次元摩耗分布計測におけるソース領域パターンニング法と特異値分解法による空間分解能　　　　　　　　　　　　　　　
長沢 裕樹, 西山 修輔, 富岡 智, 佐々木 浩一, 加納 豊広, 金子 卓
第72回応用物理学会学術講演会, Aug. 2011, Japanese, Oral presentation

ナノ時空間ダイナミクスのその場観察法による物質変換過程の解明　　　　　　　　　　　　　　　
柴山 環樹, 谷津 茂男, 渡辺 精一, 伊藤 芳浩, 富岡 智, 西山 修輔
日本顕微鏡学会, May 2011, Japanese, Oral presentation

単結晶シンチレータ中における三次元発光位置特定法　　　　　　　　　　　　　　　
西山 修輔, 富岡 智
第58回応用物理学関係連合講演会, Mar. 2011, Japanese, Oral presentation

外部透明電極と光増幅素子を用いた ナノ秒多チャンネルフレーミングカメラ　　　　　　　　　　　　　　　
田坂 陽季, 富岡 智, 佐々木 浩一
プラズマ・核融合学会第27回年会, Nov. 2010, Japanese, Oral presentation

Copmarison of OTR from rough screen with He-Ne laser　　　　　　　　　　　　　　　
Hayato Aki, Shusuke Nishiyama, Satoshi Tomioka
Proc. of the 7th Annual Meeting of Particle Accelerator Society of Japan, Aug. 2010, Japanese, Oral presentation

Two-dimensional Phase Unwrapping Using Virtual Residues　　　　　　　　　　　　　　　
Samia Heshmat, Shusuke Nishiyama, Satoshi Tomioka
第57回 応用物理学関係連合講演会, Mar. 2010, English, Oral presentation

プラズマ振動周波数測定によるプラズマ密度計測　　　　　　　　　　　　　　　
高橋 俊文, 西山 修輔, 富岡 智, 日野 友明
第26回プラズマ・核融合学会年会, Dec. 2009, Japanese, Oral presentation

分光法を用いたアルゴン励起原子温度測定　　　　　　　　　　　　　　　
本家 翼, 西山 修輔, 富岡 智, 日野 友明
第50回真空に関する連合講演会, Oct. 2009, Japanese, Oral presentation

分光法を用いたアルゴン励起原子温度測定　　　　　　　　　　　　　　　
本家 翼, 西山 修輔, 富岡 智, 日野 友明
第25回プラズマ・核融合学会年会, Dec. 2008, Japanese, Oral presentation

圧縮ベントナイトに対して得られた X線マイクロCT画像の解析　　　　　　　　　　　　　　　
富岡 智, 西山 修輔, 小崎 完, 佐藤 正知
可視化情報学会論文集, Oct. 2008, Japanese, Oral presentation

Analysis of X-ray Micro-CT Images Observed with Compacted Bentonite
TOMIOKA Satohi, NISIYAMA Shusuke, KOZAKI Tamotsu, SATO Seichi
可視化情報学会誌. Suppl. = Journal of the Visualization Society of Japan, 15 Sep. 2008, Japanese

X-Ray Micro-CT Observation of Barrier Materials for Geological Disposal of High-Level Radioactive Waste
KOIKE Ryutaro, KOZAKI Tamotsu, TAKAMATSU Hidenori, NODA Natsuko, KITAICHI Masatoshi, TOMIOKA Satoshi, NISIYAMA Shusuke, SATO Seichi
可視化情報学会誌. Suppl. = Journal of the Visualization Society of Japan, 15 Sep. 2008, Japanese

X-Ray Micro-CT Observation of Barrier Materials for Geological Disposal of High-Level Radioactive Waste
Koike Ryutaro, Kozaki Tamotsu, Takamatsu Hidenori, Noda Natsuko, Kitaichi Masatoshi, Tomioka Satoshi, Nisiyama Shusuke, Sato Seichi
Transactions of Visualization Society of Japan, 2008, Japanese

高エネルギー粒子加速器における曲線軌道荷電粒子ビーム航跡場の時間領域境界要素解析　　　　　　　　　　　　　　　
藤田 和広, 富岡 智, 川口 秀樹, 日野 友明
日本原子力学会北海道支部第25回研究発表会, Dec. 2007, Japanese, Oral presentation

Microstructural image of dry and water-saturated compacted bentonite samples observed with X-ray micro CT　　　　　　　　　　　　　　　
Satoshi Tomioka, Tamotsu Kozaki, Hidenori Takamatsu, Natsuko Noda, Shusuke Nisiyama, Naofumi Kozai, Satoru Suzuki, Seichi Sato
Workshop on long-term performance of smectitic clays embedding canisters with highly radioactive waste, Nov. 2007, English, Oral presentation
[Invited]

P20 圧縮ベントナイト内部微細構造観察へのX線マイクロCT法の適用およびその最適化
高松 英則, 野田 菜摘子, 小崎 完, 北市 雅敏, 富岡 智, 佐藤 正知
粘土科学討論会講演要旨集, 12 Sep. 2007, Japanese

粗い金属表面を用いる遷移放射光強度分布の特性　　　　　　　　　　　　　　　
宮本 伸之, 北川 広貴, 西山 修輔, 富岡 智, 榎戸 武揚
日本原子力学会北海道支部第24回研究発表会, Dec. 2006, Japanese, Oral presentation

中赤外光計測を目的とした熱吸収型可視位相変調素子の空間分解能　　　　　　　　　　　　　　　
富岡 智, 宮本 直樹, 西山 修輔, 榎戸 武揚
第6回核融合エネルギー連合講演会, Jun. 2006, Japanese, Oral presentation

遺伝的アルゴリズムによる汎用非線形最小二乗法　　　　　　　　　　　　　　　
富岡 智, 西山 修輔, 榎戸 武揚
第4回 HSSワークショップ, Mar. 2006, Japanese, Oral presentation

Infrared phase-shifting interferometer using the nitroanisole as a two-dimensional detector　　　　　　　　　　　　　　　
Naoki Miyamoto, Shusuke Nisiyama, Satoshi Tomioka, Takeaki Enoto
Optomechatronic Sensors and Instrumentation, 06 Dec. 2005, English, Oral presentation
[International presentation]

赤外画像可視化を利用した屈折率の測定　　　　　　　　　　　　　　　
阿部 謙一, 宮本 直樹, 北川 広貴, 西山 修輔, 富岡 智, 榎戸 武揚
日本原子力学会北海道支部第23回研究発表会, Dec. 2005, Japanese, Oral presentation

時間領域境界要素法における行列方程式の反復解法に関する検討　　　　　　　　　　　　　　　
藤田和広, 川口秀樹, 富岡智, 榎戸武揚
平成17年度 電気・情報関連学会北海道支部連合大会, Oct. 2005, Japanese, Oral presentation

ニトロアニソールを用いた赤外線ホログラフィによる赤外画像の可視化　　　　　　　　　　　　　　　
宮本 直樹, 西山 修輔, 富岡 智, 榎戸 武揚
核融合科学研究所画像計測研究会, Aug. 2005, Japanese, Oral presentation

遺伝的アルゴリズムによる重畳波形分離　　　　　　　　　　　　　　　
大槻 孝之, 西山 修輔, 富岡 智, 榎戸 武揚
日本原子力学会北海道支部第22回研究発表会, Dec. 2004, Japanese, Oral presentation

新規カルバゾール置換ポリアセチレンの物理特性とデバイス応用　　　　　　　　　　　　　　　
牧垣 太郎, 小塚 心尋, 宮坂 淳史, 富岡 智, 榎戸 武揚, 田畑 昌祥
第53回高分子学会討論会予稿集, Sep. 2004, Japanese, Oral presentation

遺伝的アルゴリズムを用いた逆問題解析による相対論的電子ビーム断面形状の推定　　　　　　　　　　　　　　　
大槻 孝之, 西山 修輔, 富岡 智, 榎戸 武揚
日本原子力学会北海道支部第21回研究発表会, Dec. 2003, Japanese, Oral presentation

10 Edification of Intellectual Curiosity through Simple Experiments for First Year Students
TOMIOKA Satoshi, NISIYAMA Shusuke, KITAGAWA Hiroki, ENOTO Takeaki
工学・工業教育研究講演会講演論文集, 04 Sep. 2003, Japanese

初年度学生に対する簡単な実験を通した知的好奇心の啓発　　　　　　　　　　　　　　　
富岡 智, 西山 修輔, 北川 広貴, 榎戸 武揚
平成15年度 工学・工業教育研究講演会講演論文集, Sep. 2003, Japanese, Oral presentation

遺伝的アルゴリズムを用いた相対論的電子ビーム分布の推定　　　　　　　　　　　　　　　
大槻孝之, 西山修輔, 富岡智, 榎戸武揚
核融合科学研究所画像計測研究会, Aug. 2003, Japanese, Oral presentation

The use of BEM and NN system to estimate density distribution of plasma　　　　　　　　　　　　　　　
A. Ota, S. Tomioka, S. Nisiyama, T. Enoto
International Symposium on Inverse Problems in Engineering Mechanics 2003, Feb. 2003, English, Oral presentation

光増幅素子の光電面放出電子のエネルギー特性の評価　　　　　　　　　　　　　　　
岡田直之, 西山修輔, 富岡智, 榎戸武揚
日本原子力学会北海道支部第20回研究発表会, Dec. 2002, Japanese, Oral presentation

An improvement method of the simultaneity of images on ultra high speed x-ray framing camera with the gated microchannel plate detector　　　　　　　　　　　　　　　
Yoshihiro Ito, Yasuto Katoh, Makoto Kagata, Shusuke Nisiyama, Satoshi Tomioka, Takeaki Enoto
The International Society for Optical Engineering / 25th International Congress on High-Speed Photography and Photonics, 2002, English, Oral presentation
[International presentation]

赤外線二次元検出用液晶の温度・電界依存性の研究　　　　　　　　　　　　　　　
宮本 直樹, 西山 修輔, 富岡 智, 榎戸 武揚
日本原子力学会北海道支部第19回研究発表会, Dec. 2001, Japanese, Oral presentation

赤外線実時間二段ホログラフィ干渉法の向上に関する研究　　　　　　　　　　　　　　　
野村 啓一, 宮本 直樹, 逵 由典, 富岡 智, 榎戸 武揚
電気関係学会北海道支部連合大会, Oct. 2001, Japanese, Oral presentation

Scattered field FD-TD analysis for wake-fields computation　　　　　　　　　　　　　　　
S. Nisiyama, S.Tomioka, T. Enoto
Proc. of 10th Int. Symp. on Simulation and Design of Applied Electromagnetics and Mechanics, 2001, English, Oral presentation

電子ビームによる放射電磁界への近傍金属の影響　　　　　　　　　　　　　　　
杉山 耕太郎, 西山 修輔, 富岡 智, 榎戸 武揚
日本原子力学会北海道支部第18回研究発表会, Dec. 2000, Japanese, Oral presentation

ニトロベンゼンを遠赤外線二次元検出材料として用いた二段ホログラフィー干渉法　　　　　　　　　　　　　　　
原山 武志, 榎戸 武揚, 富岡 智
日本原子力学会北海道支部 第17回研究発表会, Dec. 1999, Japanese, Oral presentation

分布ソースを有する３次元ポアッソン方程式の多重相反境界要素法解析　　　　　　　　　　　　　　　
四方純, 板垣正文, 富岡智, 榎戸武揚
日本原子力学会北海道支部 第16回研究発表会, Dec. 1998, Japanese, Oral presentation

超高速度フレームカメラのMTF特性の解析　　　　　　　　　　　　　　　
加藤 靖人, 風間 信幸, 今井 応介, 富岡 智, 榎戸 武揚
高速度撮影とフォトニクスに関する総合シンポジウム1997, Dec. 1997, Japanese, Oral presentation

FD-TD法による超高速駒取りカメラのシャッタリング特性の解析　　　　　　　　　　　　　　　
加賀田 誠, 富岡 智, 榎戸 武揚
高速度撮影とフォトニクスに関する総合シンポジウム1995, Dec. 1995, Japanese, Oral presentation

遠赤外領域ホログラフィ干渉法を目的としたHgCdTe赤外線検出器の空間解像度の改善　　　　　　　　　　　　　　　
竹内 久美子, 山下 靖二, 富岡 智, 榎戸 武揚
プラズマ核融合学会第11回年会, Mar. 1994, Japanese, Oral presentation

FD-TD法を用いる電子線加速器電子ビームの作る電磁界解析　　　　　　　　　　　　　　　
伊藤裕康, 西山修輔, 富岡智, 榎戸武揚
日本原子力学会北海道支部第11回研究発表会, Dec. 1993, Japanese, Oral presentation

CO_2レーザ干渉体系を用いるHgCdTe赤外線検出器のMTF特性の測定度の改善　　　　　　　　　　　　　　　
竹内 久美子, 富岡 智, 榎戸 武揚
電気関係学会北海道支部連合大会, Oct. 1993, Japanese, Oral presentation

FD-TD法による超高速カメラシャッタリング特性の解析　　　　　　　　　　　　　　　
榎戸武揚, 富岡智, 加賀田誠, 町谷顕
プラズマ・核融合学会第9回秋季講演会, Oct. 1992, Japanese, Oral presentation

超高速度撮影装置の開発と核融合プラズマ計測への応用　　　　　　　　　　　　　　　
榎戸 武揚, 木村 雅紀, 富岡 智, 春山 和郎, 深井 一郎, 遠藤 彰, 吉田 貴彦
北海道核融合連絡者会議第1回研究報告書, 1988, Japanese, Oral presentation

分布を持つプラズマを含む開放型共振器に対する境界要素法適用の試み　　　　　　　　　　　　　　　
富岡 智, 榎戸 武揚, 深井 一郎
日本原子力学会北海道支部第5回研究発表会, Dec. 1987, Japanese, Oral presentation

境界要素法による開放型共振器の領域分割問題の解析　　　　　　　　　　　　　　　
富岡 智, 榎戸 武揚, 深井 一郎
日本原子力学会北海道支部第4回研究発表会, Dec. 1986, Japanese, Oral presentation

境界要素法による領域分割問題の解析　　　　　　　　　　　　　　　
富岡 智, 深井 一郎, 榎戸 武揚
電気関係学会北海道支部連合大会, Oct. 1986, Japanese, Oral presentation

Three-dimensional density distribution mesurement of spieces of mixtured gas by shearing interferometry with multi-wavelength light
Grants-in-Aid for Scientific Research
01 Apr. 2022 - 31 Mar. 2025
富岡 智, 山内 有二, 宮本 直樹, 松本 裕
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), Hokkaido University, 22K04117

超高線量率陽子線治療に適したリアルタイム飛程検出法の開発
科学研究費助成事業
09 Jul. 2021 - 31 Mar. 2024
松浦 妙子, 田中 創大, 富岡 智, 橋本 孝之, 栗山 靖敏
FLASH放射線治療は，通常の放射線治療の線量率の数百倍から数千倍高い線量率（40 Gy/s程度以上）を用いる超高線量率照射法である。抗腫瘍効果を変えずに正常組織の障害発生を顕著に抑制できることが知られており，これまでの治療様式を大きく変えるインパクトがある．本研究では，数年以内に臨床利用が期待される超高線量率陽子線治療に適用する心電図検査式リアルタイム飛程検出法の実用化に向けた基盤技術開発を行うことを目標とした研究開発を行っている．本年度はまず，シミュレーション検討に用いるためにCT及び超音波の両方のイメージングに対応した人体ファントムを選定し（Model 057A，CIRS社製），音波伝搬シミュレーションの構築を開始した．まず人体ファントムを陽子線治療計画用のCT装置で撮影し，各ボクセルのCT値に対して陽子線治療に用いられているCT-相対阻止能テーブルを用いて水密度を割り当て，モンテカルロシミュレーションによって陽子線線量分布を計算した．一方で，音波発生・伝搬シミュレーションの準備として，文献を参照しながら各ボクセルに対してCT値に応じた音響特性（音速や音響インピーダンス，グルネイセン係数など）を割り当てた．人体ファントムに対して，FLASH線量率で陽子線を照射し，これを音源とした音波伝搬をシミュレーションした．音波は体表面に配置した複数のセンサーで受信する設定とした．本年度はまた，次年度予定している陽子線照射実験に用いる予定の寒天をベースとしたファントムの構造と形状の検討を行い，試作を行った．
日本学術振興会, 挑戦的研究(萌芽), 北海道大学, 21K19434

Marker-less volume imaging technique for real-time tumor tracking radiation therapy
Grants-in-Aid for Scientific Research
01 Apr. 2020 - 31 Mar. 2023
宮本 直樹, 田中 創大, 高尾 聖心, 富岡 智, 松浦 妙子, 清水 伸一
本研究では、放射線治療中に得られる2方向X線透視画像を利用し、体内マーカを利用することなく（マーカーレス）、リアルタイムに体内の3次元構造を取得するボリュームイメージング技術を開発することを目的とする。この提案技術の実現により、体内にマーカーを留置するという侵襲性のあるプロセスを無くすことができ、加えて、ボリュームイメージを得ることによる高精度な呼吸性移動対策をFLASH などの超高線量率照射を含むあらゆる照射において実施可能となる。本研究では、研究期間内に各要素技術の開発を進め、十分な質と量のデータにより精度検証を実施し、ボリュームイメージングを利用した治療ビーム照射制御の臨床的有用性を明らかにする。
2021年度は、昨年度のデジタルファントムによる画像合成精度評価に続き、実際の患者の4DCTデータによる評価を進めた。同一患者で異なる日に撮影された4DCTデータを利用し、1つの4DCTデータを変形モデリング用、残りの4DCTデータを検証に用い、モデリングの課程で得られた固有体内変形ベクトルの線形結合にもとづくボリュームイメージングにより、検証データをどこまで再現できるか評価した。合成画像の画素値と構造の再現性を評価した結果、先行研究（主にデジタルファントムでの評価）と同等の性能が得られた。したがって、放射線治療中に正確な固有値を評価することにより、標的の位置や体内構造の評価に応用できるボリュームイメージをリアルタイムで合成できると考えられ、提案手法の臨床的な実行可能性を示すことができた。
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 20H03612

Real-time volumetric image generation based on CT deformation driven by simultaneous monitoring of internal landmarks and object surface
Grants-in-Aid for Scientific Research
29 Jun. 2018 - 31 Mar. 2021
Miyamoto Naoki
We developed a method to reconstruct 3D in vivo information in real time by using the positional information of biological surfaces and in vivo markers through modeling of in vivo deformations using pre-learning data. Using a patient's 4DCT acquired for radiotherapy, we evaluated the image synthesis accuracy of the in vivo reconstruction method developed in this project as the normalized root mean square error (NRMSE) between the ground truth image and the synthesized image. The image synthesis accuracies for the training data and the validation with motion beyond the training data were about 7% and 11%, respectively. In addition, the accuracy of tumor location evaluation was less than 1 mm. These results suggest that the accuracy is sufficient for application in radiotherapy.
Japan Society for the Promotion of Science, Grant-in-Aid for Challenging Research (Exploratory), Hokkaido University, 18K19887

Three-dimensional refractive index measurement system using shear interferometer
Grants-in-Aid for Scientific Research
01 Apr. 2018 - 31 Mar. 2021
Tomioka Satoshi
In order to measure the three-dimensional refractive index distribution, a coupling method of interferometer and computed tomography can be used. As the interferometer to measure delay of wavefront due to object from different incident angles, we adopted a shearing interferometer, which always satisfies interference condition during changing incident angle since the shearing interferometer does not use a reference wave. We demonstrated that interferograms obtained with the shearing interferometer are not affected by vibration caused by changing of the incident direction. In addition, we measured the three-dimensional distribution of the refractive index of the gas near the candle flame, and the reconstructed result was qualitative agreed.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), Hokkaido University, 18K04158

Real-time tumor-tracking arc therapy for stereotactic body radiotherapy
Grants-in-Aid for Scientific Research
01 Apr. 2017 - 31 Mar. 2020
Miyamoto Naoki
In this study, we have developed the fundamental techniques to realize real-time tumor-tracking arc radiation therapy for stereotactic body radiation therapy. In order to show the clinical feasibility and effectiveness, expected treatment time and dosiemtric characteristics were evaluated. Treatment time could be reduced by the proposed treatment technique compared with the current treatment system used for real-time tumor-tracking. For the dosimetric validation, film and ion-chamber measurement with dynamic phantom was conducted. It was confirmed that the acceptable dosimetric characteristics could be achievable with the proposed technique. Dosimetric error between the measured dose and the planned dose was within 3% in ion-chamber measurement. It was suggested that the proposed method has clinical feasibility.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 17H04115

Weighted reconstruction algorithm for time varying object with incomplete projection data
Grants-in-Aid for Scientific Research
2015 - 2017
Tomioka Satoshi
In order to monitor positions and shapes of tissue inside body during radiotherapy, we propose a computed tomographic reconstruction technique with limited projection beams. In this technique, the number of angles of projection beams measured at the time of reconstruction is small and most projection beams are lacked. The lacked projection data are replaced by the projection data measured in the past. Since the past state of body is different from that at the reconstructing time, the contribution of each projection data to the reconstructed image should be modified. By applying the weighted reconstruction algorithm to take into account the contribution of the projection data which includes past projection data, we demonstrated feasibility of low exposure monitoring.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), Hokkaido University, Principal investigator, Competitive research funding, 15K06097

Development of a method for the efficient production of sonoplasmas
Grants-in-Aid for Scientific Research
01 Apr. 2012 - 31 Mar. 2015
SASAKI Koichi, TOMIOKA Satoshi, NISHIYAMA Shusuke, TAKADA Noriharu
In this work, we have proposed the mechanism by which the efficient production of sonoplasmas is achieved in a sonoplasma production system with the help of a punching metal plate. Small bubbles are produced at the sharp edges of holes on the punching metal plate. They are transported by the primary Bjerknes force toward the bottom side of the vessel, and are trapped at the dip in the distribution of the ultrasonic pressure. These processes result in standing cavitation bubbles with a high density. The present method is unique as a method for producing liquid-phase plasmas without using high voltages. It can be utilized for enhancing the rates of various sonochemistry processes.
Japan Society for the Promotion of Science, Grant-in-Aid for Challenging Exploratory Research, Hokkaido University, 24654185

Migration behavior of materials in clay buffer materials in geological disposal of high-level radioactive waste and migration-controlled corrosion of iron
Grants-in-Aid for Scientific Research
01 Apr. 2011 - 31 Mar. 2014
KOZAKI Tamotsu, WATANABE Naoko, TOMIOKA Satoshi, KOZAI Naofumi
For the safety assessment of the geological disposal, it is necessary to understand the corrosion behavior of iron in bentonite buffer material and identify important parameters to affect the corrosion. In this study, corrosion of iron and migration of ions in compacted bentonite under electrical gradient were studied. In addition, hydraulic property of sedimentary rock sample was studied by conducting hydraulic conductivity measurement and X-ray micro CT observation of the rock sample. Hydraulic conductivity measurements were also made for Fe(II)-montmorillonite to understand the effect of the alteration of bentonite on the performance as the buffer material.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 23360417

Non-destractive three-dimensional temperature measurement using interferometric tomography
Grants-in-Aid for Scientific Research
2012 - 2014
TOMIOKA Satoshi, NISHIYAMA Shusuke
In order to measure nondestructive three-dimensional temperature distribution of heated gas, we have developed an incident angle variable interferometer. The interfergram from each incident angle is converted to phase image by newly developed phase unwrapping algorithms. The three-dimensional distribution is reconstructed by a computed tomography.
To demonstrate validity of this system, we have measured three-dimensional gas temperature distribution around candle flame. From a comparison with a result by using a thermocouple, we conclude that the developed measurement system can measure the nondestructive three-dimensional distribution successfully.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), Hokkaido University, Principal investigator, Competitive research funding, 24560216

Study of nano spatiotemporal dynamics on phase transformation in advanced materials by in situ observation technique
Grants-in-Aid for Scientific Research
2009 - 2011
SHIBAYAMA Tamaki, WATANABE Seiichi, YATSU Shigeo, ITOH Yoshihiro, TOMIOKA Satoshi, NISHIYAMA Syusuke, NORIHITO Sakaguchi
In this study, we carried out the development of in-situ observation experimental apparatus on nano spatiotemporal dynamics to combine the streak camera which had many successful results of the measurements in pico second phenomena on the laser inertial confinement fusion reaction at the target region of the fuel pellets and the various high speed CCD cameras in order to find out a solution of the only remaining issues to improve the temporal resolution and extend the recording time in TEM for three years from FY2009 to FY2011. We installed the newly developed experimental apparatus to our present TEM and investigate the crack initiation point or the multi crack propagation at the interface of the joint under electron irradiation and ion irradiation by recording in nano spatiotemporal resolution where so far it has not been done by us, and revealed the interaction between the multi crack paths which grew in high speed and nano sized defects.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), Hokkaido University, 21241025

Three dimensional measurement of refractive index using phase tomography
Grants-in-Aid for Scientific Research(基盤研究(C))
2009 - 2011
Satoshi TOMIOKA, Shusuke NISHIYAMA, Takashi KAMIYAMA, Hiroto SAKASHITA
In measurement of distribution of gas temperature or concentration of liquid, the correct measurement is difficult, since the condition of the object to be measured is changed due to the sensor (e.g thermo couple) itself. In this study, we propose a phase tomography that is a coupling method of optical interferometer and computed tomography that is three dimensional non-destructive measurement. Experimental measurement of three dimensional gas temperature distribution agree with theoretical distribution qualitatively.
Ministry of Education, Culture, Sports, Science and Technology, 基盤研究(C), 北海道大学, Principal investigator, Competitive research funding, 21560197

Performances of barrier materials in geological disposal : mechanistic evaluation through mesoscopic analysis
Grants-in-Aid for Scientific Research
2008 - 2010
KOZAKI Tamotsu, TOMIOKA Satoshi, NISIYAMA Shusuke, KAMIYAMA Takashi, SASAKI Takayuki, KOZAI Naofumi
As a fundamental study for the safety assessment of the geological disposal of high-level radioactive waste, the mesoscopic structures of the expected barrier materials (bentonite and sedimentary rock) were characterized by X-ray diffraction analysis, X-ray micro CT observation and μ-PIXE analysis. The hydraulic conductivity, diffusivity, and distribution coefficient of radioactive tracers were determined as indicators in order to relate the barrier performance to the mesoscopic structures.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 20360415

Basic Research for four-dimensional stereotactic radiotherapy
Grants-in-Aid for Scientific Research
2005 - 2009
SHIRATO Hiroki, KANEKO Junichi, NISHIYAMA Syusuke, KATOH Chietsugu, AOYAMA Hidefumi, SEKI Koh-ichi, ONIMARU Rikiya, NISHIOKA Takeshi, MORITA Koichi, DATE Hiroyuki, TAKADA Eiji, TOMIOKA Satoshi, KUDO Kohsude, ONODERA Yuya, KAMISHIMA Tamotsu, ONIMARU Rikiya, SHIMIZU Shinichi, SAKUHARA Yusuke, OYAMA Noriko, ABO Daisuke, TAGUCHI Hiroshi
We developed a four-dimensional (4-D, space and time) focal positron emission localizer, FPEL, using two sets of BGO scintillators, photo-electric multiplier, and collimators. A narrow (5-mm in diameter) 45-MeV electron beam was controlled to irradiate a target with an accuracy of 0.1mm in 4D coordinates automatically if the amount of positron emitters at the target exceeds the threshold. A mouse model was established to irradiate the tumor in which FDG is accumulated. Using the FPEL, 45-MeV electron beam hit the tumor in mice which move in front of the beam exit with the amplitude resembling human respiration. Tumor without fiducial gold marker disappeared within a week after the irradiation. Basis for 4D stereotacic radiotherapy was established successfully.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research on Priority Areas, Hokkaido University, 17016002

New Material Characterization method by Using a pulsed Neutron Transmission Spectroscopic Radiography
Grants-in-Aid for Scientific Research
2005 - 2007
KIYANAGI Yoshiaki, KAMIYAMA Takashi, KANEKO Jyunichi, TOMIOKA Satoshi, TAKENAKA Nobuyuki, FURUSAKA Michihiro
Spectroscopic neutron radiography using a pulsed neutron can give structural information of materials since it has neutron cross section data at each pixel. Especially, at low energy region of the cross section Bragg edges appear which reflect the crystal structure of the materials. The shift of the Bragg position gives strain of the crystal. We performed the experiment on the iron sample which would have strain due to bending. We could clearly observe the strain position and amount of the strain. It was found that the strain appeared on specific crystal planes. It is also indicated that the total neutron cross section around the Bragg edge depended on the grain size of the crystalitte and showed that the cross section decreased proportional to the grain size by a model experiment. Furthermore, the crystal structural change around the welded position of the SS-Iron sample and Iron-Iron sample. The crystal structure change had similar tendency in both sample. Naturally, far from the weld position the cross section showed the typical feature of Bragg edges of iron and SS, as approaching the weld position the edge became sharper, and at weld position the edge had a sharp edge implying the isotropic distribution of the crystallittes. On the other hand, at high energy we can utilize the resonance absorption to get image of elements or nuclei. We performed transmission measurement of the heavy material to get CT image, and it is suggested that the method was also useful for imaging the element distribution and also that we may use this to measure the temperature by analyzing the resonance peak. We developed the sensor of the imaging detector based on Gd composite. We succeeded in making a test detector and also obtained images by using the neutron beam.
As mentioned above, the spectroscopic neutron imaging using the pulsed neutron sources are very powerful tool to investigate micro structure of the materials, such as strain, crystallite size, distribution of crystallite and so on. Now, the operation of the big proton accelerator neutron source is just about to take place. We will get much higher quality data by using such high intensity sources and also get much detailed information about the sample materials. Therefore, we are now on the stage to develop the method further to promote the industrial applications.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), Hokkaido University, 17206096

Analytical method to solve Schrodinger Equations with Genetic Algorithm
Grants-in-Aid for Scientific Research(基盤研究(C))
2005 - 2007
Satoshi TOMIOKA, 榎戸 武揚, Shusuke NISIYAMA
This study presents the new method to solve Schroedinger equations for some electron orbits using genetic algorithm. The Schroedinger equation is represented as a partial differential equation of wave function, and it also includes an eigen value as unknown variable.Our approach to solve this equation is based on an eigen-function expansion of a wave function. Firstly, this partial differential equation is transformed to the integral equation including a fundamental solution. When we impose a particular condition to the set of functions to expand, the integration with fundamental solution can be given by recurrence formula without integration In these processes, since both gridding to solve a partial equation and numerical integrations are not required, any approximations are not involved.To determine coefficients of the eigen-function we apply a genetic algorithm. The genetic algorithm is a method to emulate evolution of species. The coefficients, a set of coefficients, and the Schroedinger equation are, respectively, considered as genes a individual, and environment. In the system there are many individuals at a time. If some individuals have better fitness to environment they produce children having parents' gene. The system evolves gradually to have many better individuals.Using these combination, we succeeded to solve the Schroedinger equation for the spherical symmetrical potential such as hydrogen atom. For more complex model with unsymmetrical potential, the convergence of the genetic algorithm was not good. However, we found the integral equation can be transformed to algebraic simultaneous equations, which does not need help of the genetic algorithm. And we succeeded to solve the orbit of hydrogen atom under electric field.In addition, the genetic algorithm was improved. This improvement gives us not only the method to solve a equation that is the purpose of this study, but also the solution of fitting problems with discontinuous functions.
Ministry of Education, Culture, Sports, Science and Technology, 基盤研究(C), 北海道大学, Principal investigator, Competitive research funding, 17560049

相対論的電子ビームの共振器による非接触型時間プロファイルの計測
科学研究費補助金(奨励研究(A))
2000 - 2001
富岡 智
本研究の目的は、電子ビームから放出されるパルス状電磁界の時間プロファイル測定である。このパルスは2.85GHzの加速周波数とその高調波より構成されており、それらの複素スペクトルを測定すれば、元の時間プロファイルを決定できる。複素スペクトルとは各成分の振幅の絶対値と位相を表している。通常の計測法では、各成分の絶対値のみしか分からないが、二つの周波数成分を同時に計測し、さらに、この一方に移相器(遅波回路)を挿入することにより、二つの周波数成分間の位相差が計測できる。本研究では、この測定に、共振周波数を自由に選ぶことが出来、さらに複数の周波数成分を同時にフィルタリング(選択)することも出来る開放型共振器を採用した。開放型共振器には、電磁波の入射ポートを設け、大きな出力を得るために、出力検出用の四本のモノポールアンテナを直接共振器に挿入した。挿入した四本のアンテナは、各々、基本波(2.85GHz)、第二、第三、第四高調波を主として検出する位置に設置した。このうち、第四高調波は出力が弱く複素スペクトルの計測は不可能であった。これらのアンテナの内の、基本波の出力に移相器を挿入し、他の高調波成分の一つの出力と合成し、その位相遅れを計測した。また、各々の成分単体の出力を計測した。なお、入力ポートから各アンテナまでの位相遅れについても、同様の方法で計測し、各周波数成分は入力ポートにおける複素振幅に換算できる。以上により、基本波から第三高調波までではあるが、複素スペクトルを求め、加速器の時間プロファイルを求めることができた。この結果は、他の計測法との定量的な比較は行ってはいないが、定性的には妥当な結果を示していた。本来は、加速器からの放射電磁界は第五高調波程度まで延びているため充分な精度の計測はできなかったが、本研究で提案した複素スペクトルの計測法は、実現可能な手法であることが示された。
文部科学省, 奨励研究(A), 北海道大学, Principal investigator, Competitive research funding, 12750373

Study on the composite measurement method for micro-structure and profile of electron beam
Grants-in-Aid for Scientific Research
1998 - 1999
ENOTO Takeaki, ITOH Hiroyasu, KAWAGUCHI Hideki, TOMIOKA Satoshi
We proposed several new measurement techniques for composite measurement method. The results of them are as the followings.
(a) Measurement of micro-pulse width of LINAC beam using standing wave measurement: We propose a new technique based on transformation from the time domain into the spatial domain to determine the time pulse width. It requires measurements of only spatial standing wave distributions. These distributions can be detected with only use of the low frequency detector systems (e.g., oscilloscope, A/D converter etc.) The availability of this technique is shown by the numerical demonstration and the result of experiments.
(b) Transverse profile estimation with measurement of electromagnetic fields: To demonstrate the availability of real time measurement system for transverse profile, we made the software system that includes a pseudo signal generator, the Kalman filter and parallel genetic algorithms. This system can simulate time dependent changes of beam profile. The estimated result is compared with the given profile. As the result of the time response analysis, we showed this system gave us almost good estimations except rare occurred instability.
c Electron beam measurement by X-ray framing camera: We investigated the spatial resolution of X-ray framing camera for 2-dimensional measurement of LINAC electron beam profile. In generally, the test chart is applied to measure the spatial resolution. However, good test chart is not found for the soft X-ray. Thus, we propose a new technique named virtual test chart algorithm that use only a knife edge. Further we proposd a method of improving the spatial resolution using the magnetic field.
(d) Simultaneity improvement of the ultra-high speed camera: We pointed out a problem about coincidence characteristics of image when ultra-high speed camera operates with sub-nano-second shuttering, and proposed the improvement way considering the shape of electrode. As the result of numerical analysis, the disperse in time is reduced from 30 pico-seconds to 5 pico-seconds.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), HOKKAIDO UNIVERSITY, 10450154

Measurement of infrared light　　　　　　　　　　　　　　　
1999
Competitive research funding

Inverse problem using genetic algorithm　　　　　　　　　　　　　　　
1999
Competitive research funding

相対論的電子ビームの非接触型プロファイルモニタの開発
科学研究費補助金(奨励研究(A))
1997 - 1998
富岡 智
今年度の研究成果を、信号取得に関するハードウェアと、信号処理に関する分散処理を行う逆問題解析ソフトウェアに分けて、以下に記す。・信号取得系(ハードウェア)昨年度評価を行ったスロットアンテナの他、今年度は、開放型共振器の試作・評価を線形加速器を用いて行った。開放型共振器の特徴として、鏡面間隔を実験をしながら変更することができ、複数の周波数を選択的に検出すること挙げられる。実験結果から昨年度行った解析と定性的に一致することが確認でき、さらに、その出力は十分であることが分かった。ただし、装置がスロットアンテナに比べて、若干大規模になるため、現在のところ、スロットアンテナとバンドパスフィルタを組み合わせた体系の方が有望である。また、バンドパスフィルタとの組合せにより、複数の周波数成分の位相差の検出の可能性を見出した。このことは、開放型共振器が断面内分布のみならず、軸方向分布のプロファイルモニターへの応用の可能性を示している。・信号処理系(ソフトウェア)昨年度、完成させた遺伝的アルゴリズムに加え、新たにカルマンフィルタ、疑似データ生成系を新たに作成し、総合評価を行った。カルマンフィルタによる測定誤差の軽減により、遺伝的アルゴリズムの推定の効率を高めることが確認できた。一方、ほぼ正しい推定はできているが稀に特異な解に収束する場合があらわれた。本システムは、推定すべきパラメータ数が測定データ数より多いため、評価関数により最適なものを選んでいるが、その評価関数の選び方にさらなる工夫が必要であることを示している。残念ながら、これについては今後の検討課題である。また、遺伝的アルゴリズムのさらに内側では、境界要素法を用いているが、この境界要素法の高精度化、開放領域問題への新たなアプローチを開発し、その成果を公表した。
文部科学省, 奨励研究(A), 北海道大学, Principal investigator, Competitive research funding, 09750466

時間項を含むマクスウェル波動方程式の境界要素法における解の安定性に関する研究
科学研究費補助金(奨励研究(A))
1992 - 1992
富岡 智
文部科学省, 奨励研究(A), 北海道大学, Principal investigator, Competitive research funding, 04855077

Relativistic electron beam measurement　　　　　　　　　　　　　　　
1992
Competitive research funding

Plasma diagnostics using electromagnetic wave　　　　　　　　　　　　　　　
1990
Competitive research funding

放射線計測システム
Patent right, 加納 豊広, 金子 卓, 萩原 康正, 宮田 学, 富岡 智, 西山 修輔, 株式会社デンソー, 国立大学法人北海道大学
特願2010-276007, 10 Dec. 2010
特開2012-122962, 28 Jun. 2012
201203099047387679

放射線計測システム
Patent right, 金子 卓, 加納 豊広, 宮田 学, 萩原 康正, 富岡 智, 西山 修輔, 株式会社デンソー, 国立大学法人北海道大学
特願2010-263973, 26 Nov. 2010
特開2012-112892, 14 Jun. 2012
201203030562144517