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It has been proposed that the axial vibration reduction method using multi-coil-motor which can precisely control torque and synthetic magnetic field. In this system, the centrifugal force due to the unbalance can be reduced by driving the coil in a way that reduces vibration. However, there is a problem that the attractive and repulsive forces generated by the coil are not constant. In this paper, a new coil selection system is proposed using MATLAB/Simulink in order to keep these forces generated by the coils constant. The stability of these forces generated by the coils is verified, and the results are compared with those of the conventional system.

The inquiry activity of science and mathematics in high school is one of very important educational issues. The PET bottle rocket is considered to be a good theme because it requires a wide range of knowledge in high school physics, including the laws of energy conservation, mass conservation and momentum conservation and the state equation of gas. Though the experiment of PET rocket is popular, the detail of the theoretical mechanism is not understood well still now. In this paper, we consider a vertical Launch of PET Bottle Rocket. We derive a theoretical equation that takes into account the air resistance in the motion of a PET bottle rocket, and then perform numerical simulations for solving the equation. To know a power of thrust, the PET bottle rocket is fixed and the water level change in the container is measured by filming the super-slow motion. We compare the simulated values derived from the theoretical equation with the actual measured values by firing the PET bottle rocket. It verifies the validity of the theoretical equation

現在、国内で普及している重粒子線治療装置の敷地面積は非常に大きく、導入コストも大きい。そこで量子科学技術研究開発機構では超伝導電磁石の技術を利用したシンクロトロンの小型化や高強度レーザー技術を用いた加速入射器により既存の病院施設に設置できるサイズである次世代の小型重粒子治療装置「量子メス」の研究開発を進めている。量子メスの実現にあたり、入射器・シンクロトロンの小型化と共に加速器出口から照射エリアまでビーム輸送系(高エネルギービーム輸送系:HEBT)を短縮することが敷地面積を小さくするにあたり重要課題となる。本研究では回転ガントリーを採用した場合における回転ガントリー入口までのHEBT及び回転ガントリーの輸送系について検討を行った。 量子メスにおける治療では200段階以上のエネルギーのビームがシンクロトロンから供給され最大エネルギーは430 MeV/u、最低エネルギーは56 MeV/uである。HEBT及び回転ガントリーはすべての段数のビームエネルギーに対して最適な光学条件を満たす必要がある。本研究ではこの2つのエネルギー条件においてHEBT及び回転ガントリーの光学設計を行い、敷地面積の縮小化について検討を行った。本研究ではその現状について報告する。, 第17回日本加速器学会年会

The biological effectiveness of charged-particle beams depends not only on dose but also on radiation quality. The radiation quality of charged-particle beams has been most commonly represented by the linear energy transfer (LET) in radiation biology studies. We investigated a new therapeutic technique of charged-particle therapy in which two or more ion species are delivered in one treatment session for optimizing the dose and LET distributions in a patient. We refer the therapeutic technique as an Intensity Modulated composite PArtiCle Therapy (IMPACT). Helium, carbon, oxygen and neon ions are considered as ion species for the IMPACT. To demonstrate the effectiveness of the IMPACT for simultaneous optimization of dose and LET distributions, an IMPACT plan was made for a prostate case. In accordance with the prescriptions, LETs in prostate, planning target volume (PTV), and rectum could be adjusted at 80 keV/μm, at 50 keV/μm, and below 30 keV/μm, respectively, while keeping the dose to the PTV at 2 Gy uniformly. The IMPACT enables the optimization of the dose and the LET distributions in a patient, which will maximize the potential of charged-particle therapy by expanding the therapeutic window.

An isotope separation on-line (ISOL) system is necessary to provide 11C ions for heavy-ion cancer therapy with simul-taneous verification of the dose distribution using positron emission tomography. To realize the ISOL system, we have developed elementary instruments in the ISOL system, such as a proton-irradiation target, a molecule separation system, and a singly-charged ion source, and performed tests to verify their performances. As a next step of the development, we are planning to start an experiment of on-line production of singly-charged 11C ions at the proton irradiation port of the NIRS-cyclotron facility. In this paper, we present those elementary instruments, their performance and the on-line production experiment.

The propagation characteristic of the electromagnetic wave to the human head is examined in frequency 3.35 GHz. Human head is designed as the layered structures such as skin, fat, bone, Dura, CSF (Cerebrospinal fluid) and brain. EM wave Radiation and Electric filed propagation are numerically examined by FDTD (finite different time domain) method of two dimensional Maxwell's equation. For 2D FDTD, E polarization case of Transverse magnetic (TM) mode are implemented with Matlab programming. The electric field point source is kept near cylindrical human head and then analyze the nature of wave propagation to the tissue layer by layer using the impedance mismatch and specific absorption rate (SAR). Only some part of head that located near the source has the high level of E field absorption rate and then it sharply decreases. The electric field absorption rate reach peak in Skin and CSF layer. This paper also mentions the relationship between the rising of SAR rate and the reflection rate at each tissue layer interface.

A new compact rotating gantry for carbon-ion radiotherapy is being designed. This gantry consists of three combined-function superconducting-magnets having a bending angle of 90 degrees. The dipole field of the superconducting magnets is designed to be Bmax=5.02 T, corresponding to a bending radius of 1.32 m for transporting carbon ions having kinetic energy of 430 MeV/u. This superconducting magnet also has three independent super-conducting quadrupole-coils, which are to be wound inside of the dipole coil for beam focusing. The dipole and quadrupole coils are to be electrically isolated in the magnet, and connected to independent power supplies, so that each field component can be independently excited. Having used the combined-function superconducting magnets, the size of the rotating gantry would become very compact; the length and radius are 5.1 m and 4.0 m, respectively. The magnetic field distributions of the super-conducting magnets were calculated with a three-dimensional electromagnetic field solver, Opera-3d code. With the calculated fields, the superconducting coils were optimized, so as to obtain uniform field distributions. In this paper, the design of the beam optics as well as the superconducting magnets is presented.

A superconducting rotating-gantry for carbon-ion radiotherapy was developed. This isocentric gantry can transport carbon ions having kinetic energies of between E=430-56 MeV/u to an isocenter over an irradiation angle of ±180 degrees, and is further capable of performing three-dimensional raster-scanning irradiation. The rotating gantry equips combined-function superconducting magnets. Since these magnets can provide both dipole and quadrupole fields, no quadrupole magnet is required for beam focusing. Having used the combined-function superconducting magnets and optimized the layout of the gantry as well as the beam optics, the length and radius of the gantry became approximately 13 m and 5.5 m, respectively, which are comparable to those for proton gantries. Construction of the entire rotating-gantry system was completed by the end of September, 2015. Having performed beam commissioning over various combinations of gantry angles and beam energies, we could successfully obtain the designed beam quality, which satisfies the requirements of scanning irradiation. Cancer treatments using the superconducting rotating-gantry were started since May, 2017.

Recently, the development of the Monte Carlo calculation technology in the field of radiation medicine is remarkable. The Monte Carlo method is used for the dose calculation of treatment planning in the field of the radiation therapy. And some dose evaluation tools using Monte Carlo method have been already developed in the field of the radiation diagnostics. Here we report about clinical situation and research situation on the use of Monte Carlo calculation in the recent radiation medicine field.

Previously, we have succeeded in exploiting a new high sensibility eddy current testing (ECT) sensor called the infinite (∞) coil. This paper proposes the other new ECT sensor to realize a further higher sensibility sensor than those of our previous one. The new sensor utilizes the magnetic fields in the parallel directions to a tested target surface, and this makes it possible to construct a shape whose sensing coil could be entirely surrounded by the exciting coil. Surrounding the sensing coil entirely by the exciting coil makes it possible to work the exciting coil as if a shielding coil to the external electromagnetic noise. Thus, good signal to noise ratio is expected and has been confirmed by the numerical simulations as well as practical experiments.Key Words : Eddy current testing, Non-destructive testing, ∞ coil

[Purpose] In the dose distribution measurement for QA / QC in high-precision radiation therapy such as particle therapy, high accuracy and high spatial resolution is required. This research group has been developing a detector for high-spatial resolution two-dimensional dose distribution measurement using glass GEM (Gas Electron Multiplier) and scintillation gas. Based on the measurement results so far, it is known that this detector has small LET dependence, and it is expected to be applied to dose distribution measurement of particle therapy. In this study, a test QA plan for heavy particle radiation therapy was prepared and two-dimensional distribution measurement using this detector was carried out. [Methods] In this detector, the ionization distribution in the scintillation gas is electronically amplified by a glass GEM. Then, the distribution of the generated light is captured from the back side of the ITO (Tin-doped Indium Oxide) transparent electrode of the Anode portion by using a cooled CCD camera. Irradiation experiments were carried out using 290 MeV/u carbon ion beam at NIRS-HIMAC. A geometric dose distribution was formed using a bolus collimator, and the dose distribution of the treatment planning device was compared with the light quantity distribution measured by this detector. [Results] The light quantity distribution obtained by this detector corresponded to the dose distribution of the treatment plan relatively, but the accuracy of the low dose area was reduced. And, it was found that it is necessary to investigate the stability, such as discharge occurred in the high dose area when the gain was increased. It is considered that optimization such as explication of the cause of deterioration in accuracy of the low dose region and adjustment of the GEM gain is necessary. [Conclusion] Although the light quantity distribution corresponding to the dose distribution of carbon beam was obtained from this detector, in order to use it for QA etc., improvement in accuracy and stability is necessary., 第117回日本医学物理学会学術大会

Heavy ion radiotherapy achieves high QOL and excellent tumor control even for radio-resistant tumors. QST-NIRS has developed a next generation heavy ion radiotherapy device that reduces the cost and size of this device and further improves tumor control, and it is called quantum scalpel. The quantum scalpel consists of a laser driven ion accelerator as an injector and a superconducting synchrotron and a rotational gantry. The synchrotron can be installed in a room of 10 m square using a 4T combined function superconducting magnets. The rotating gantry transports the beam with superconducting magnets and irradiates multiple ion beams to achieve the high LET field. We report on the current state of the overall design of this quantum scalpel.

Various type impact and vibration isolation devices have been widely used to protect the objects particularly in the field of medical, biology, or any precision industries. These devices are mainly composed of the spring, damper and actuator. This paper proposes another new simpler method to insulate the impact disturbance by using the principle of center of percussion. When the plane rigid body is forced impulsively, the instant stationary point must be on the plane rigid body. This instant stationary point is called "center of percussion". This paper shows the basic equations, simulation and the several experimental results to realize the impact insulator using center of percussion., Ⅲ.論文集

Proton therapy has the physical advantage of a Bragg peak that can provide a better dose distribution than conventional x-ray therapy. However, radiation exposure of normal tissues cannot be ignored because it is likely to increase the risk of secondary cancer. Evaluating secondary neutrons generated by the interaction of the proton beam with the treatment beam-line structure is necessary; thus, performing the optimization of radiation protection in proton therapy is required. In this research, the organ dose and energy spectrum were calculated from secondary neutrons using Monte Carlo simulations. The Monte Carlo code known as the Particle and Heavy Ion Transport code System (PHITS) was used to simulate the transport proton and its interaction with the treatment beam-line structure that modeled the double scattering body of the treatment nozzle at the National Cancer Center Hospital East. The doses of the organs in a hybrid computational phantom simulating a 5-y-old boy were calculated. In general, secondary neutron doses were found to decrease with increasing distance to the treatment field. Secondary neutron energy spectra were characterized by incident neutrons with three energy peaks: 1×10, 1, and 100 MeV. A block collimator and a patient collimator contributed significantly to organ doses. In particular, the secondary neutrons from the patient collimator were 30 times higher than those from the first scatter. These results suggested that proactive protection will be required in the design of the treatment beam-line structures and that organ doses from secondary neutrons may be able to be reduced.

Scintillation detectors are widely used for measuring radiation. A scintillation detector is composed of a photodetector and a scintillator that emits photons when it absorbs ionizing radiation. A PIN photodiode is a kind of photodetector which has been used conventionally. An avalanche photodiode (APD) is another kind of photodetector that has come into use recently. Since the APD can amplify the photocurrent by applying a high reverse voltage, output signals from the APD are less likely to be affected by background noise than those from the PIN photodiode. We have evaluated the performance of scintillation detectors with either an APD or PIN photodiode based on energy resolution, linearity, and long-term stability. We found that the energy resolution of the APD is about twice as good as that of the PIN photodiode, and that the linearity of both detectors is equally good. The instability of the PIN photodiode was less than 2% after 7 hours, which was a factor of three smaller than that of the APD. We believe that the APD instability is due to temperature variation. In conclusion, scintillation detectors with an APD are useful for high-resolution spectroscopy of ionizing radiation if their temperature is properly controlled., PINフォトダイオードは従来用いられてきた光検出器の一種である．一方，アバランシェフォトダイオード（APD）は電子と空孔の雪崩効果を利用することで，信号の増幅が可能な光検出器であり，PINフォトダイオードに比べ，ノイズの影響を受けにくくなることが期待される．本研究では，これら2つの光検出器を用いたシンチレーション放射線検出器について，検出器としての性能をエネルギー分解能・直線性・長期安定性の3点から検証した．その結果，エネルギー分解能はAPDの方が約2倍優れており，直線性は共に良く，PINフォトダイオードの不安定性は7時間の観察で2％以下であり，APDより3倍以上変動が小さいことが分かった．信号波高の変動と温度変化には相関が見られるので変動の主な原因はAPDの温度変化であると考えられる．ゆえに，APDの温度を一定に保つ機器を導入すれば，APDは高分解能放射線計測に有効な光検出器となるであると結論される．, 理学 物理学

Positron Emission Tomography (PET) is a modern diagnostic method for cancer. A medical agent labeled with a positron-emitting radioactive isotope called a tracer is injected into the body. Positrons emitted by the tracer annihilate electrons, and pairs of gamma rays are consequently emitted in opposite directions. Coincidence measurements of the two gamma rays can determine the position of positron- electron annihilation. If we use a tracer that tends to concentrate within cancer cells, the PET scan becomes useful for imaging cancer within the body. In this study, 22Na was used as the positron emitter. Gamma rays were detected by 8 scintillation detectors consisting of GAGG (Gd3Al2Ga3O12) scintillators mounted on avalanche photodiodes. We carried out coincidence measurements of the two gamma rays, and demonstrated the principle behind PET scans. Additionally, we demonstrated the single-photon emission computed tomography (SPECT) scan used in cancer testing, and compared its performance with that of the PET scan., 近年の癌検査法として、放射性同位元素で標識した薬剤を体内に入れ、体内からの放射線を測定することで、癌の位置を特定する「PET検査」と呼ばれる方法が確立されている。PET検査では、放射性同位体の中でも「β＋崩壊」を起こす同位体を用いる。β＋崩壊では、陽電子が放出されるが、これが他の電子と衝突すると、電子と陽電子は対消滅し、2本のγ線が反対方向に放射される。この2本のγ線を同時計測すれば、陽電子の発生した位置を決定できるので、あらかじめβ＋崩壊核を含む薬剤を用いて癌細胞を標識しておくことで、癌の位置を特定することができる。今回の実験では、β＋崩壊を起こす22Naと、放射線が当たると発光する「シンチレータ」、光を電流に変換する「アバランシェフォトダイオード」を用いて、PET検査を再現し、その原理を実証してみた。また、同じく癌検査で用いられるSPECT検査も再現し、PET検査とSPECT検査の比較を行った。, 理学 物理学

A new Si-based small detector named D-Space has been developed for space dosimetry. It is based on the D-shuttle dosimeter for gamma-ray. The response to proton beam with the energy of 160 MeV was obtained and the LET value was estimated.

When we analyze wave propagation, we should model the ground as if it is extended infinitely in the limited analytical region. Now we try to make infinite ground model by FEM and CIP method. CIP method is usually used to analyze sound, noise and electromagnetic field. In this research, we try to make Wave Transmitting Boundary by CIP method in 2-dimensional FEM. We chase it in this study about Primary wave.

The aim of this study in to measure the distributions of multiple isotopes in small animal SPECT study. In multi-isotope SPECT system, images reconstructed with the counts of primary photons emitted from a low energy photopeak radionuclide is distorted by Compton scattered photons originating in a high energy photopeak radionuclide.. In this paper, applied an artificial neural network method to quantitatively measure the distribution of activities in the simultaneous data acquisition with a multiple isotope SPECT study and the accuracy of our proposed method was evaluated.

Multiple-energy operation was developed to realize fast 3D scanning irradiation for carbon-ion radiotherapy. The operation can output various carbon-ion beams with different energies in a single synchrotron cycle. The beam control system applying this operation also has been developed to quickly provide the beam energy and intensity required from the irradiation control system. The performance of multiple-energy operation was verified by the experiments at HIMAC. The operation system could output the beams of more than 197 different energies in 63 seconds. The beam intensity could be controlled for their energies without large ripple and overshoot. Experimental irradiation for prostate cancer treatment was also successfully performed, and its result proved that our system can greatly reduce the irradiation time.

We compared the signal-to-noise ratio (SNR) of magnetic resonance spectroscopy (MRS) using two different sequences, namely, Spin ECho, full Intensity Acquired Localized spectroscopy (SPECIAL) and Point-REsolved SpectroScopy (PRESS). The SNR by SPECIAL was 15% higher than PRESS, which could be attributed to the difference in echo time., 第45回日本磁気共鳴医学会大会

Eddy current testing (ECT) is one of the most representative nondestructive testing methods for metallic materials, parts, structures and so on. Operating principle of ECT is based on two major properties of the magnetic field. One is that alternating magnetic field induces eddy current in conducting materials. Thereby, an input impedance of the magnetic field source, i.e., electric source, depends on the eddy current path. Second is that the magnetic field distribution depends not only on the exciting but also on the reactive magnetic fields caused by the eddy currents in targets. Former and latter are the impedance sensing and magnetic flux sensing types, respectively.This paper concerns with an optimization of a new magnetic flux sensing type sensor named “∞ coil”. Exciting and sensing coils are composed of ∞ shape coil and a finite length solenoid coil wound on ferrite bar, respectively. Development of this ∞ coil fully depends on the 2D and 3D finite elements method modeling. According to the simulation results, we have worked out two types of ∞ coils. Practical experiments reflect the validity of both simulation and design aims, quite well. Thus, we have succeeded in developing ∞ coil having a higher sensibility compared with that of conventional one.

The turbulent flow in a duct with curvature was investigated by measuring the three dimensional flow fields. Because of the secondary flow influenced by centrifugal force in a curved duct, the effect of duct contraction and expansion were examined. The cross sectional size of the rectangular duct was 120mm by 2４0mm, with a curvature of 200°. The experiments were conducted for three duct geometries: a constant duct width （the standard case）, a contraction in duct width, and a duct expansion. The changes in duct width took place from the latter half of the duct curvature as it transitioned to the straight duct section. The results indicated that for the case of an expanding duct, the velocity defect flow was larger, turbulent intensity increased, and the turbulent boundary layer thickened and expanded in three dimensions, as compared with the standard straight duct case. When the flow was contracted, the turbulent intensity and the turbulent boundary layer thickness both decreased, with greater uniformity of the velocity profiles, as compared with the standard case.

Eddy current testing (ECT) is one of the most representative nondestructive testing methods for metallic materials, parts, structures and so on. Operating principle of ECT is based on the two major properties of magnetic field. One is that alternating magnetic field induces eddy current in all of the conducting materials. Thereby, an input impedance of the magnetic field source, i.e., electric source, depends on the eddy current path. Second is that the magnetic field distribution depends only on the exciting but also the reactive magnetic fields caused by the eddy currents in targets. Former and latter are the impedance sensing and magnetic flux sensing types, respectively. This paper concerns with an optimization of a new magnetic flux sensing type sensor named "∞ coil" whose exciting and sensing coils are composed of the ∞ shape and finite length solenoid coil wound ferrite bar, respectively. Optimization of this ∞ coil fully depends on the 3D finite elements methods. According to the 3D finite element simulation results, we have successfully carried out the optimum size of two exciting coils and a sensing coil.

An eddy current sensors have various uses, for example metal detection and determination, nondestructive inspection, and position detection. However, there are few studies which show the influence of a conductor on the impedance of a detector coil using a theoretical formula. This paper shows the simplified calculation method on impedance of a planar coil that can be found from an equivalent circuit by considering that a conductor plate is one turn of coil which form changes according to displacement. The impedance corresponding to the overlap length of a conductor plate was calculated about the planar rectangular coil and the planar triangular coil. The calculated value was compared with the measured value and the calculated value of finite element method. The calculated value of impedance of rectangular coil and triangular coil agreed with the measured value within an error of ± 5.98%. Mutual inductance between the planar coil and conductor plate was calculated from the area ratio of planar coil and overlap., Article, 日本AEM学会誌. 21(2):234-239 (2013)

It was clarified that underactuated dynamic bipedal walkers with free ankles can generate fast-convergent level gaits by achieving constraint on impact posture. This paper then identifies the condition for achieving deadbeat gait generation through mathematical investigations of simple rimless spoked walkers and proposes a method for generating fast-convergent gaits based on the obtained results. First, we simplify the transition functions for the state error of the stance phase of a passive rimless wheel by eliminating the steady step period. Second, we consider an active rimless wheel that generates ballistic gaits on level ground and show that the transition function of the stance phase can be specified in the same manner as the passive case. Based on the theoretical results, we design a control law for achieving deadbeat gait generation and investigate the validity through numerical simulations. The physical meaning of the derived transition function is also discussed. Furthermore, we extend the method to an underactuated rimless wheel with a torso by applying a discrete-time output deadbeat control. Through mathematical and numerical investigations, it is clarified that the driving effect that changes from acceleration to deceleration tends to achieve deadbeat generate generation.

The binary filter system to change beam properties was installed on the C-8 beam line in the general purpose exposure room of the NIRS-Cyclotron facility in order to alter beam properties. The plates in the binary filter system are made of poly (methyl methacrylate) (PMMA), which acts as a water-equivalent material. To evaluate the water-equivalent thicknesses of the PMMA plates, Bragg curves of an 80 MeV proton beam in a water phantom were measured with each PMMA plate or without any plates. The water-equivalent thicknesses of the filters were derived as displacements of Bragg peak with an accuracy of 10 micrometer. The mean ratio between real and water-equivalent thicknesses of the plates was calculated to be about 1.16.

A superconducting rotating-gantry for carbon-ion radiotherapy was developed. This isocentric rotating gantry can transport carbon ions having the maximum kinetic energy of Emax=430 MeV/u to an isocenter with irradiation angles of over ±180 degrees, and is further capable of performing three-dimensional raster-scanning irradiation. By using combined-function superconducting magnets, we could design and construct a compact rotating gantry for carbon-ion radiotherapy. Construction of the gantry structure begun since early 2014, and installation of the entire gantry system to the Heavy Ion Medical Accelerator in Chiba (HIMAC) complex was completed by the end of September, 2015. Beam commissioning subsequently begun since October, 2015, and carbon ions having kinetic energies of between E=430-48 MeV/u, as accelerated by the HIMAC upper synchrotron, were successfully transported with the rotating gantry to the isocenter. We will present the recent progress as well as the overview of the superconducting rotating-gantry.

Postural control during quiet stance has mainly been studied by assessing the displacement of the center of foot pressure (COP). It has been suggested that descriptive statistics based on the averaging of COP measures over time could conceal the control principles underlying observed postural dynamics and time series analysis would be needed to reveal them. Recently, researchers have used various fractalmethods to study the long-range correlations in COP signals and have reported important results, including (1)the COP fluctuations during quiet stance are fractional Brownian motions (close to 1/f fluctuations); and (2)the transition from persistent to anti-persistent correlations (crossover) occurs in the velocity of spontaneous postural sway, not in the position, which indicates that the control of spontaneous postural sway is velocity-based. This paper focuses on these two observations and reviews the relevant concepts and analytical methods of fractal or self-similar time series to suggest that (1)stabilogram diffusion analysis and detrended fluctuation analysis are valid and reliable to analyze the COP position and velocity data; (2)appropriate interpretations of obtained results require knowledge of the statistical characteristics of fractional Brownian motions and corresponding functional Gaussian noises; and (3)the diffusion coefficient or scaling exponents characterizing the diffusion property and the correlation structure of COP position and velocity data provide information that may lead to understanding the functional state of the postural control system during quiet stance.

A dielectric nanorod antenna is studied at optical wavelengths using the FDTD method. Consideration is first given to a modification of a metal-insulator-metal (MIM) waveguide for feeding. To efficiently excite the dielectric nanorod, we introduce a T-shaped exciter between the nanorod and the MIM waveguide. Next, the radiation characteristics of the dielectric nanorod antenna are evaluated in free space. It is found that a high directive gain of 10 dBi is obtained.

A new optical, non-destructive method of detecting and imaging individual heavy charged particle tracks using Fluorescent Nuclear Track Detectors (FNTD) is investigated as a possible spectroscopic technology for heavy charged particles of low and high linear energy transfer (LET). The technique uses new luminescent aluminum oxide single crystals having aggregate oxygen vacancy defects and doped with Mg (Al2O3:C,Mg) in combination with laser scanning confocal fluorescence microscopy. Spectroscopic capabilities of this new method were demonstrated for energetic heavy ions of LETH2O ranging from 1 to 730 keV/µm. Applications of this technology include neutron detection and dosimetry, radiobiology study using protons and heavy ions, microdosimetry, space radiation dosimetry, as well as nuclear and particle physics research.

Radial organization of dysplastic cerebral cortices was hypothesized and magnetic resonance diffusion tensor imaging was performed for an infant who had a dysplasia in the right cerebral cortex. Absolute value of the inner product of the normal vector to the cerebral surface and the first eigen vector (that depicts the direction of the largest eigen value of diffusion tensor) was calculated for each pixel. The absolute value of the inner product was significantly larger for the dysplastic side than for the contralateral normal side of the brain.

A two-dimensionally position sensitive dosimetry system has tested for different dosimetric applications in a radiation therapy facility with a carbon beam. The system consist of a scintillating screen, mirror, mounted at the beam-exit side of a water phantom and it is observed by a low noise CCD camera with an integration time. Comparison between light distribution and ionization chamber measurement was carried out with carbon ion beam at HIMAC.

Space Radiation and Heavy Ion in Therapy 2015

The aim of this study in to measure the distributions of multiple isotopes in small animal SPECT study. In multi-isotope SPECT system, images reconstructed with the counts of primary photons emitted from a low energy photopeak radionuclide is distorted by Compton scattered photons originating in a high energy photopeak radionuclide. In this paper,we applied an artificial neural network method to quantitatively measure the distribution of activities in the imultaneous data acquisition with a multiple isotope SPECT study and the accuracy of our proposed method was evaluated.

The authors have been working in development of a FDTD dedicated computers for numerical simulation of electromagnetic fields. In the FDTD dedicated computers, there are two kinds of architectures which are oriented for very large scale simulations or high performance computations. In this paper, VHDL cording and FPGA implementation of the large scale simulation type of the FDTD dedicated computer are presented as the final stage of the FDTD machine developments. It is also shown that numerical simulations of microwave phenomena by the FDTD machine has good agreements with that of C language simulations.

The longitudinal ultrasonic wave was irradiated on a specimen surface in water at an angle of 30 deg to generate the surface acoustic wave (SAW) on the surface. The intensity of SAW was measured under different conditions, and it was found that the intensity of SAW decreased during propagating on the specimen surface greatly compared to the ultrasonic wave traveling in the waver. Then two SAWs were propagated on the plate surface in the opposite direction and were overlapped to generate the standing interference wave. Small alumina particles were scattered in a region where the standing interference wave was generated to distribute the particles following the standing wave. However, there was no formation of the sinusoidal distribution of the particles.

Armor block stability for the mound of sloping breakwaters was examined by 2-D model tests. Damage patterns of armor blocks at the mound berm were reproduced by wave force tests. By the action of breaking wave, armor blocks at the offshore side of mound were uplifted by the vertical wave force, and overturned by. the wave induced flow. Based on the stability test results, the stability number of armor blocks was formulated as the function of relative depth, relative mound height and sea bottom slope. Furthermore, the relationship between the damage level and the number of wave action was shown for storm wave conditions exceeding the design wave height.

A computer code for charring ablation and thermal response analysis has been developed for simulation of one-dimensional transient thermal behavior of multi-layer stack of isotropic charring ablation materials used for re-entry capsules. A mathematical model of charring ablation including governing equations is summarized. Analytical solutions of several thermal response problems with or without ablation agreed very well with numerical results that are obtained with the charring ablation analysis code. Arc-heated tests of CFRP ablator models were carried out and measured results including temperature response data were compared with the simulation results of the ablation analysis code. The test results and the simulation results agreed very well. Measurements of the successfully recovered USERS/REV ablator were carried out. The measured results of the in-depth temperature history in the ablator, the char depth, the surface recession, etc. agreed well with the simulation results using the ablation analysis code. These results show that the ablation analysis code based on the present mathematical model are available for the thermal response prediction of CFRP ablator used in the re-entry capsules such as USERS/REV., 資料番号: AA0048710004, レポート番号: JAXA-RR-04-045

Arrays of dc-superconducting quantum interference devices (dc-SQUIDs) consisting of at least 100 repeated dc-SQUID elements connected in series were investigated experimentally and analytically to obtain a low noise current amplifier. The dependences of flux noise on the number of the elements and the number of turns of the input coil were examined. It was found that the flux noise is significantly influenced by the dynamic resistance of the array when the number of the elements exceeds 100, although the influence by the dynamic resistance for a single dc-SQUID is negligibly small. It was also found that the flux noise does not depend on the turn number of the input coil. These results agreed well with the measured flux noise for SQUID arrays constructed using a Nb/AlOx/Nb fabrication process. An ultra low current noise of 1 pA/√Hz was achieved using a SQUID array amplifier consisting of 128 dc-SQUID elements, each of which had a 7-turn input coil and a mutual inductance of 460 pH. On the basis of an equation for the flux noise, device parameters were optimized systematically. The optimized SQUID amplifier achieved a dynamic range of 87 dB for input signals of 50 kHz bandwidth, which is sufficiently wide for X-ray detection applications.

DGV (Doppler Global Velocimetry) is a system to measure velocity of particles crossing a laser sheet, by analyzing the scattered doppler shifted frequency of a light sheet. The light frequency shift is very weak because of the very low speed of the particles compared to the speed of light. In order to overcome this problem, an absorption line of the molecular iodine is used: the absorption of iodine depends strongly on the light frequency going through the iodine vapor. By this mean, it is possible to measure the scattered light intensity going through the iodine and normalize it to the scattered light: this ratio gives us the percentage of light absorbed by the iodine and therefore the doppler shifted frequency. The frequency shift can be traced back to particle velocity., 長崎大学工学部研究報告 Vol.34(63) p. 17-24, 2004

DGV (Doppler Global Velocimetry) is a system to measure velocity of particles crossing a laser sheet, by analyzing the scattered doppler shifted frequency of a light sheet. The light frequency shift is very weak because of the very low speed of the particles compared to the speed of light. In order to overcome this problem, an absorption line of the molecular iodine is used: the absorption of iodine depends strongly on the light frequency going through the iodine vapor. By this mean, it is possible to measure the scattered light intensity going through the iodine and normalize it to the scattered light: this ratio gives us the percentage of light absorbed by the iodine and therefore the doppler shifted frequency. The frequency shift can be traced back to particle velocity.

ZnO thin films were prepared on polyethylene terephthalate (PET) substrates using the scanning plasma method. We investigate the dependence of the scanning frequency and magnetic flux density on the substrate temperatures. We found the substrate was kept at low temperatures by modulating magnetic field and magnetic field frequency., 長崎大学工学部研究報告 Vol.33(61) p. 53-56, 2003

ZnO thin films were prepared on polyethylene terephthalate (PET) substrates using the scanning plasma method. We investigate the dependence of the scanning frequency and magnetic flux density on the substrate temperatures. We found the substrate was kept at low temperatures by modulating magnetic field and magnetic field frequency.

Accelerated heavy-ion beams has unique characteristics from the radiobiological point of view. This characteristic makes advantages and difficulties on heavy-ion radiotherapy, also makes difficult to understand the response of irradiated cells. Linear energy transfer (LET) of heavy-ion beams changes with depth in materials, and this change modifies the relative radiobiological effectiveness (RBE). Radiobiological effects were higher for lighter ion-beams at the same LET. The RBE increased with the increase of LET, showed a peak at around 100-200 keV/um, then decreased with farther increase of LET. These LET-RBE spectra shifted to higher LET region, the maximum RBE values decreased, and width of the peak of the RBE increased with increase of atomic number of accelerated ions. The peak of the RBE was only found in DNA-double strand break repair cells, but not in repair deficient cell strains.

The number of tumor cells grow exponentially, and if they are irradiated, some part of cells fall into death. The effect will depend upon the amount of radiation. In this paper, I tried to simulate the number of cells on some parametric assumption, if they get multi-divided irradiation, using "Mathematica", which is a software for mathematics and graphical display. When I calculate, the interval of irradiation is not necessarily equal interval. This method will not only be useful for evaluation of multi-divided irradiation effect but also for evaluation of any other analogous effects.

The aim of this study was to describe the culculated leg joint torque's behavior during vaulting when the centre of pressure (COP) was assumed to be fixed. The subject vaulted on the springboard used in the vaulting of gymmnastics. The board reaction force (BRF) acting on the gymnast was calculated by subtracting the inertial force of the springboard from the ground reaction force. The ankle, knee and hip joint torque were calculated by assuming the COP was fixed in two ways. The ball of foot and the centre between toe and heel were used for the fixed COP. There were large difference between two type of calculated joint torque. This suggests that the accuracy of the COP is important for calculate the joint torque.

In this paper, conditions of simple insulation curing of test specimens were studied, for purposes of strength control of concrete structures in cold weather. The temperature histories of the specimens in the simple insulation curing boxes corresponding to those of the concrete structures were researched by means of concrete experiments and temperature analysis by finite element method. Based on the result of the experiments and the analysis, the conditions of simple insulation curing of test specimens corresponding to the temperature history of concrete structures in cold weather were able to be given by empirical formulae. The accuracy of the formulae was proved by the experiment.

An isocentric superconducting rotating-gantry for heavy-ion therapy is being designed. This rotating gantry can transport heavy ions having 430 MeV/u to an isocenter with irradiation angles over 0-360 degrees, and is further capable of performing the fast raster-scanning irradiation. Combined-function superconducting magnets were designed by using a 3D electromagnetic-field solver. To verify the design of the magnets, beam tracking simulations were performed. In this paper, results of 3D field calculations on the magnets as well as beam tracking simulations are described.

重粒子線がん治療において、高度な照射治療を目的とした重粒子照射装置である小型超伝導回転ガントリーの製造が現在進行中である。この回転ガントリーは0度から360度とあらゆる角度からの重粒子ビーム照射を可能とし、これまでの固定ポートを用いた治療よりも精度の高い照射治療が可能となる。我々は回転ガントリーの小型軽量化のため、偏向電磁石に二重極成分と四重極成分を独立に励磁可能な超伝導電磁石を設計し、製作を進めている。また、この回転ガントリーでは三次元スキャニング照射法を用いた治療が行われる。スキャンされたビームを超伝導電磁石で輸送し、治療照射を行うことから、超伝導電磁石には高い磁場均一度が求められる。本研究では、ガントリーの小型化に大きく貢献している超伝導電磁石の磁場分布を精度良く測定した。測定には複数のホール素子を用い、磁石中心軌道に沿わせたレール上を移動させながらホール電圧を測定する自動システムにより磁場分布を三次元的にマッピングした。磁場測定の結果から、二極コイル単体励磁において予期せぬ四極成分が観測された。このような四極成分がある場合に、治療で必要とされる照射野の確保、及び平行ビームにするため、線形近似による軌道計算を行い、各超伝導電磁石の四極コイル電流値を最適化した。また、磁場測定から得た磁場分布を用いて粒子のトラッキングシミュレーションを行い、線形近似による軌道計算との比較を行った。 Manufacture of superconducting rotating-gantry for heavy-ion radiotherapy is currently in progress. This rotating gantry can transport heavy ions having 430 MeV/nucleon to an isocenter with irradiation angles of over 0-360 degrees, and enables advanced radiation-therapy. To reduce the size and weight of the rotating gantry, we designed superconducting magnets that can independent excite dipole and quadrupole field. The three-dimensional scanning-irradiation method is performed in this rotating gantry. Therefore, uniformity of magnetic field is quite important, since scanned beams traverse through these superconducting magnets before reaching to the isocenter. In the present work, we precisely measured the magnetic-field distributions of the superconducting magnets for the rotating gantry. We used Hall probes to measure the magnetic-flux density. The magnetic-field distributions were determined by measuring Hall voltage, while moving the Hall probes on a rail, which has the same curvature as a center trajectory of beams. The measured-field distributions were compared with designed distributions by using a three-dimensional electromagnetic-field solver, the OPERA-3D code. Furthermore, beam-tracking simulations were performed by using the measured magnetic-field distributions to verify the design of the superconducting magnets., 第11回日本加速器学会年会